feat(extensions): add GitHub handler extension and env var access (#62)

* feat(extensions): add GitHub handler extension and env var access

- add github-handler example extension that runs Kit as a GitHub
  collaborator inside Actions: parses the event, gates on
  author_association, drives the agent, posts comments, and opens PRs
- seed the Yaegi interpreter with os.Environ() in the loader and test
  harness so extensions can read env vars (e.g. GITHUB_EVENT_PATH) via
  os.Getenv/LookupEnv/Environ without mutating the host environment
- document env var access, the new extension, and env-aware testing
  across the docs site, README, and kit-extensions skill

Part of #60

* fix(extensions): harden github-handler command parsing and subprocesses

- only trigger on /kit at the start or end of a comment line, ignoring
  incidental mid-sentence mentions like "please review /kit behavior"
- bound git/gh subprocess calls with a 30s timeout via CommandContext so
  a stalled network call or auth prompt cannot hang the Actions job
- add a regression test for the mid-sentence mention case

Part of #60

README.md

@@ -28,6 +28,7 @@ A powerful, extensible AI coding agent CLI with multi-provider support, built-in
 - **Interactive TUI**: Rich terminal interface powered by Bubble Tea with streaming, syntax highlighting, and custom rendering
 - **Session Management**: Tree-based conversation history with branching support
 - **Non-Interactive Mode**: Script-friendly positional args with JSON output
+- **GitHub Integration**: Scaffold a GitHub Actions workflow with `kit github install` to run Kit as a collaborator/reviewer on `/kit` comments
 - **ACP Server**: Run Kit as an [Agent Client Protocol](https://agentclientprotocol.com) agent over stdio
 - **Go SDK**: Embed Kit in your own applications with full agent lifecycle events (30+ event types) and behavior-modifying hooks
 
@@ -128,6 +129,12 @@ temperature: 0.7
 stream: true
 thinking-level: off       # off, none, minimal, low, medium, high
 no-core-tools: false      # set to true to disable all built-in core tools
+
+# Skills — all three keys are optional
+no-skills: false          # set to true to disable all skill loading
+skill:                    # explicit skill files/dirs (disables auto-discovery)
+  - /path/to/skill.md
+skills-dir: ""            # override project-local directory for auto-discovery
 ```
 
 All of the above keys can also be set programmatically via the SDK
@@ -203,6 +210,11 @@ mcpServers:
 --prompt-template        Load a specific prompt template by name
 --no-prompt-templates    Disable prompt template loading
 
+# Skills
+--skill                  Load skill file or directory (repeatable)
+--skills-dir             Override the project-local skills directory for auto-discovery
+--no-skills              Disable skill loading (auto-discovery and explicit)
+
 # Generation parameters
 --max-tokens             Maximum tokens in response (default: 8192, auto-raised up to 32768 for models with larger known output limits)
 --temperature            Randomness 0.0-1.0 (default: 0.7)
@@ -249,6 +261,12 @@ kit install --uninstall <pkg> # Remove an installed package
 # Skills
 kit skill                    # Install the Kit extensions skill via skills.sh
 
+# GitHub integration
+kit github install           # Scaffold .github/workflows/kit.yml (run Kit on '/kit' comments)
+kit github install --model anthropic/claude-sonnet-4-5-20250929
+kit github install --force   # Overwrite an existing workflow file
+kit github install --no-secret # Skip the offer to set the provider secret via the gh CLI
+
 # ACP server
 kit acp                      # Start as ACP agent (stdio JSON-RPC)
 kit acp --debug              # With debug logging to stderr
@@ -467,6 +485,45 @@ Placeholders inside fenced code blocks (```) and inline code spans are ignored.
 
 Disable templates with `--no-prompt-templates` or load a specific template with `--prompt-template <name>`.
 
+## GitHub Integration
+
+Kit can run as an automated collaborator/reviewer inside GitHub Actions. The
+`kit github install` command scaffolds a workflow that triggers when someone
+comments `/kit ...` on an issue or pull request review, runs the agent
+non-interactively in the runner, and lets it respond.
+
+```bash
+kit github install
+```
+
+This writes `.github/workflows/kit.yml`. By default the command prompts for the
+model (pre-filled with a sensible default); pass `--model` to skip the prompt.
+If the [`gh` CLI](https://cli.github.com/) is detected on your `PATH` and the
+provider API key is present in your environment, you'll be offered the option to
+store it as a repository secret automatically.
+
+The generated workflow:
+
+- Triggers only on `issue_comment` and `pull_request_review_comment` (`types: [created]`).
+- Runs only when the comment begins with the `/kit` command token.
+- Restricts triggers to repository owners, members, and collaborators (via `author_association`).
+- Uses least-privilege `permissions` and `persist-credentials: false`.
+- Authenticates git/PR operations with the built-in `secrets.GITHUB_TOKEN` and
+  the provider via a repository secret (e.g. `ANTHROPIC_API_KEY`).
+
+After committing the workflow and setting the provider secret, comment
+`/kit <your request>` on any issue or pull request to trigger Kit.
+
+The runtime that reads the event context, enforces permissions, drives the agent,
+and posts the response back is the
+[`github-handler`](examples/extensions/github-handler) example extension.
+
+| Flag | Description |
+| --- | --- |
+| `--model` | Provider/model to write into the workflow |
+| `--force` | Overwrite an existing workflow file |
+| `--no-secret` | Skip the offer to set the provider secret via the `gh` CLI |
+
 ## Session Management
 
 Kit uses a tree-based session model that supports branching and forking conversations.

cmd/extension_context.go

@@ -4,13 +4,11 @@ import (
 	"context"
 	"fmt"
 	"os"
-	"strings"
 
 	"github.com/spf13/viper"
 	"golang.org/x/term"
 
 	"github.com/mark3labs/kit/internal/app"
-	"github.com/mark3labs/kit/internal/auth"
 	"github.com/mark3labs/kit/internal/extbridge"
 	"github.com/mark3labs/kit/internal/extensions"
 	"github.com/mark3labs/kit/internal/models"
@@ -35,451 +33,276 @@ type extensionContextDeps struct {
 // the three print routes appropriately for their phase (startup buffering
 // vs. live runtime routing).
 //
-// This consolidates two near-identical 400-line literal expressions that
-// previously appeared inline in runNormalMode.
+// The headless half (data access, state, options, tree navigation, skills,
+// templates, model resolution, subagents) comes from extbridge.BaseContext;
+// this function overlays the TUI-specific fields and overrides SetModel /
+// ReloadExtensions with TUI-aware versions.
 func buildInteractiveExtensionContext(deps extensionContextDeps) extensions.Context {
 	kitInstance := deps.kitInstance
 	appInstance := deps.appInstance
 	usageTracker := deps.usageTracker
-	ctx := deps.ctx
 
-	return extensions.Context{
-		CWD:         deps.cwd,
-		Model:       deps.modelName,
-		Interactive: deps.interactive,
-		PrintBlock: func(opts extensions.PrintBlockOpts) {
-			appInstance.PrintBlockFromExtension(opts)
-		},
-		SendMessage:   func(text string) { appInstance.Run(text) },
-		CancelAndSend: func(text string) { appInstance.InterruptAndSend(text) },
-		Abort:         func() { appInstance.Abort() },
-		IsIdle:        func() bool { return !appInstance.IsBusy() },
-		Compact: func(cfg extensions.CompactConfig) error {
-			return appInstance.CompactAsync(cfg.CustomInstructions, cfg.OnComplete, cfg.OnError)
-		},
-		SendMultimodalMessage: func(text string, files []extensions.FilePart) {
-			parts := make([]kit.LLMFilePart, len(files))
-			for i, f := range files {
-				parts[i] = kit.LLMFilePart{
-					Filename:  f.Filename,
-					Data:      f.Data,
-					MediaType: f.MediaType,
-				}
-			}
-			appInstance.RunWithFiles(text, parts)
-		},
-		GetSessionUsage: func() extensions.SessionUsage {
-			if usageTracker == nil {
-				return extensions.SessionUsage{}
-			}
-			stats := usageTracker.GetSessionStats()
-			return extensions.SessionUsage{
-				TotalInputTokens:      stats.TotalInputTokens,
-				TotalOutputTokens:     stats.TotalOutputTokens,
-				TotalCacheReadTokens:  stats.TotalCacheReadTokens,
-				TotalCacheWriteTokens: stats.TotalCacheWriteTokens,
-				TotalCost:             stats.TotalCost,
-				RequestCount:          stats.RequestCount,
-			}
-		},
-		Exit: func() { appInstance.QuitFromExtension() },
-		SetWidget: func(config extensions.WidgetConfig) {
-			kitInstance.Extensions().SetWidget(config)
-			go appInstance.NotifyWidgetUpdate()
-		},
-		RemoveWidget: func(id string) {
-			kitInstance.Extensions().RemoveWidget(id)
-			go appInstance.NotifyWidgetUpdate()
-		},
-		SetHeader: func(config extensions.HeaderFooterConfig) {
-			kitInstance.Extensions().SetHeader(config)
-			go appInstance.NotifyWidgetUpdate()
-		},
-		RemoveHeader: func() {
-			kitInstance.Extensions().RemoveHeader()
-			go appInstance.NotifyWidgetUpdate()
-		},
-		SetFooter: func(config extensions.HeaderFooterConfig) {
-			kitInstance.Extensions().SetFooter(config)
-			go appInstance.NotifyWidgetUpdate()
-		},
-		RemoveFooter: func() {
-			kitInstance.Extensions().RemoveFooter()
-			go appInstance.NotifyWidgetUpdate()
-		},
-		PromptSelect: func(config extensions.PromptSelectConfig) extensions.PromptSelectResult {
-			ch := make(chan app.PromptResponse, 1)
-			appInstance.SendPromptRequest(app.PromptRequestEvent{
-				PromptType: "select",
-				Message:    config.Message,
-				Options:    config.Options,
-				ResponseCh: ch,
-			})
-			resp := <-ch
-			if resp.Cancelled {
-				return extensions.PromptSelectResult{Cancelled: true}
-			}
-			return extensions.PromptSelectResult{Value: resp.Value, Index: resp.Index}
-		},
-		PromptConfirm: func(config extensions.PromptConfirmConfig) extensions.PromptConfirmResult {
-			ch := make(chan app.PromptResponse, 1)
-			def := "false"
-			if config.DefaultValue {
-				def = "true"
-			}
-			appInstance.SendPromptRequest(app.PromptRequestEvent{
-				PromptType: "confirm",
-				Message:    config.Message,
-				Default:    def,
-				ResponseCh: ch,
-			})
-			resp := <-ch
-			if resp.Cancelled {
-				return extensions.PromptConfirmResult{Cancelled: true}
-			}
-			return extensions.PromptConfirmResult{Value: resp.Confirmed}
-		},
-		PromptInput: func(config extensions.PromptInputConfig) extensions.PromptInputResult {
-			ch := make(chan app.PromptResponse, 1)
-			appInstance.SendPromptRequest(app.PromptRequestEvent{
-				PromptType:  "input",
-				Message:     config.Message,
-				Placeholder: config.Placeholder,
-				Default:     config.Default,
-				ResponseCh:  ch,
-			})
-			resp := <-ch
-			if resp.Cancelled {
-				return extensions.PromptInputResult{Cancelled: true}
-			}
-			return extensions.PromptInputResult{Value: resp.Value}
-		},
-		SetUIVisibility: func(v extensions.UIVisibility) {
-			kitInstance.Extensions().SetUIVisibility(v)
-			go appInstance.NotifyWidgetUpdate()
-		},
-		GetContextStats: func() extensions.ContextStats {
-			s := kitInstance.GetContextStats()
-			return extensions.ContextStats{
-				EstimatedTokens: s.EstimatedTokens,
-				ContextLimit:    s.ContextLimit,
-				UsagePercent:    s.UsagePercent,
-				MessageCount:    s.MessageCount,
-			}
-		},
-		SetEditor: func(config extensions.EditorConfig) {
-			kitInstance.Extensions().SetEditor(config)
-			// Always use a goroutine for NotifyWidgetUpdate: prog.Send()
-			// deadlocks if called synchronously from inside BubbleTea's
-			// Update() handler. All call sites use go-routines uniformly.
-			go appInstance.NotifyWidgetUpdate()
-		},
-		ResetEditor: func() {
-			kitInstance.Extensions().ResetEditor()
-			go appInstance.NotifyWidgetUpdate()
-		},
-		GetMessages: func() []extensions.SessionMessage {
-			return kitInstance.Extensions().GetSessionMessages()
-		},
-		GetSessionPath: func() string {
-			return kitInstance.GetSessionPath()
-		},
-		AppendEntry: func(entryType string, data string) (string, error) {
-			return kitInstance.Extensions().AppendEntry(entryType, data)
-		},
-		GetEntries: func(entryType string) []extensions.ExtensionEntry {
-			return kitInstance.Extensions().GetEntries(entryType)
-		},
-		SetState: func(key string, value string) {
-			kitInstance.Extensions().SetState(key, value)
-		},
-		GetState: func(key string) (string, bool) {
-			return kitInstance.Extensions().GetState(key)
-		},
-		DeleteState: func(key string) {
-			kitInstance.Extensions().DeleteState(key)
-		},
-		ListState: func() []string {
-			return kitInstance.Extensions().ListState()
-		},
-		SetEditorText: func(text string) {
-			appInstance.SetEditorTextFromExtension(text)
-		},
-		SetStatus: func(key string, text string, priority int) {
-			kitInstance.Extensions().SetStatus(extensions.StatusBarEntry{
-				Key:      key,
-				Text:     text,
-				Priority: priority,
-			})
-			go appInstance.NotifyWidgetUpdate()
-		},
-		RemoveStatus: func(key string) {
-			kitInstance.Extensions().RemoveStatus(key)
-			go appInstance.NotifyWidgetUpdate()
-		},
-		GetOption: func(name string) string {
-			return kitInstance.Extensions().GetOption(name)
-		},
-		SetOption: func(name string, value string) {
-			kitInstance.Extensions().SetOption(name, value)
-		},
-		SetModel: func(modelString string) error {
-			// Capture previous model for the ModelChange event.
-			previousModel := kitInstance.Extensions().GetContext().Model
-			err := kitInstance.SetModel(context.Background(), modelString)
-			if err != nil {
-				return err
-			}
-			// Notify TUI so it updates model in status bar.
-			p, m, _ := models.ParseModelString(modelString)
-			appInstance.NotifyModelChanged(p, m)
-			// Update the context's Model field so handlers see it.
-			kitInstance.Extensions().UpdateContextModel(modelString)
-			// Fire OnModelChange event to extensions.
-			kitInstance.Extensions().EmitModelChange(modelString, previousModel, "extension")
-			// Update usage tracker with new model info for correct token counting.
-			if usageTracker != nil {
-				newProvider, newModel, _ := models.ParseModelString(modelString)
-				if newProvider != "unknown" && newModel != "unknown" && newProvider != "ollama" {
-					registry := models.GetGlobalRegistry()
-					if modelInfo := registry.LookupModel(newProvider, newModel); modelInfo != nil {
-						// Check OAuth status for Anthropic models
-						isOAuth := false
-						if newProvider == "anthropic" {
-							_, source, err := auth.GetAnthropicAPIKey(viper.GetString("provider-api-key"))
-							if err == nil && strings.HasPrefix(source, "stored OAuth") {
-								isOAuth = true
-							}
-						}
-						usageTracker.UpdateModelInfo(modelInfo, newProvider, isOAuth)
-					}
-				}
-			}
-			return nil
-		},
-		GetAvailableModels: func() []extensions.ModelInfoEntry {
-			return kitInstance.GetAvailableModels()
-		},
-		EmitCustomEvent: func(name string, data string) {
-			kitInstance.Extensions().EmitCustomEvent(name, data)
-		},
-		Complete: func(req extensions.CompleteRequest) (extensions.CompleteResponse, error) {
-			return kitInstance.ExecuteCompletion(context.Background(), req)
-		},
-		SuspendTUI: func(callback func()) error {
-			return appInstance.SuspendTUI(callback)
-		},
-		RenderMessage: func(rendererName, content string) {
-			renderer := kitInstance.Extensions().GetMessageRenderer(rendererName)
-			if renderer == nil || renderer.Render == nil {
-				appInstance.PrintFromExtension("", content)
-				return
-			}
-			w, _, _ := term.GetSize(int(os.Stdout.Fd()))
-			if w == 0 {
-				w = 80
-			}
-			rendered := renderer.Render(content, w)
-			appInstance.PrintFromExtension("", rendered)
-		},
-		ReloadExtensions: func() error {
-			err := kitInstance.Extensions().Reload()
-			if err != nil {
-				return err
-			}
-			// Notify TUI that widgets/status/commands may have changed.
-			go appInstance.NotifyWidgetUpdate()
-			return nil
-		},
-		GetAllTools: func() []extensions.ToolInfo {
-			return kitInstance.Extensions().GetToolInfos()
-		},
-		SetActiveTools: func(names []string) {
-			kitInstance.Extensions().SetActiveTools(names)
-		},
-		RegisterTheme: func(name string, config extensions.ThemeColorConfig) {
-			tc := func(c extensions.ThemeColor) [2]string { return [2]string{c.Light, c.Dark} }
-			ui.RegisterThemeFromConfig(name,
-				tc(config.Primary), tc(config.Secondary),
-				tc(config.Success), tc(config.Warning),
-				tc(config.Error), tc(config.Info),
-				tc(config.Text), tc(config.Muted),
-				tc(config.VeryMuted), tc(config.Background),
-				tc(config.Border), tc(config.MutedBorder),
-				tc(config.System), tc(config.Tool),
-				tc(config.Accent), tc(config.Highlight),
-				tc(config.MdHeading), tc(config.MdLink),
-				tc(config.MdKeyword), tc(config.MdString),
-				tc(config.MdNumber), tc(config.MdComment),
-			)
-		},
-		SetTheme: func(name string) error {
-			return ui.ApplyTheme(name)
-		},
-		ListThemes: func() []string {
-			return ui.ListThemes()
-		},
-		ShowOverlay: func(config extensions.OverlayConfig) extensions.OverlayResult {
-			ch := make(chan app.OverlayResponse, 1)
-			appInstance.SendOverlayRequest(app.OverlayRequestEvent{
-				Title:       config.Title,
-				Content:     config.Content.Text,
-				Markdown:    config.Content.Markdown,
-				BorderColor: config.Style.BorderColor,
-				Background:  config.Style.Background,
-				Width:       config.Width,
-				MaxHeight:   config.MaxHeight,
-				Anchor:      string(config.Anchor),
-				Actions:     config.Actions,
-				ResponseCh:  ch,
-			})
-			resp := <-ch
-			if resp.Cancelled {
-				return extensions.OverlayResult{Cancelled: true, Index: -1}
-			}
-			return extensions.OverlayResult{
-				Action: resp.Action,
-				Index:  resp.Index,
-			}
-		},
-		SpawnSubagent: func(config extensions.SubagentConfig) (*extensions.SubagentHandle, *extensions.SubagentResult, error) {
-			return extbridge.SpawnSubagent(ctx, kitInstance, config)
-		},
-		// -------------------------------------------------------------------
-		// Tree Navigation API
-		// -------------------------------------------------------------------
-		GetTreeNode: func(entryID string) *extensions.TreeNode {
-			node := kitInstance.GetTreeNode(entryID)
-			if node == nil {
-				return nil
-			}
-			return &extensions.TreeNode{
-				ID:        node.ID,
-				ParentID:  node.ParentID,
-				Type:      node.Type,
-				Role:      node.Role,
-				Content:   node.Content,
-				Model:     node.Model,
-				Provider:  node.Provider,
-				Timestamp: node.Timestamp,
-				Children:  node.Children,
-			}
-		},
-		GetCurrentBranch: func() []extensions.TreeNode {
-			nodes := kitInstance.GetCurrentBranch()
-			result := make([]extensions.TreeNode, len(nodes))
-			for i, n := range nodes {
-				result[i] = extensions.TreeNode{
-					ID:        n.ID,
-					ParentID:  n.ParentID,
-					Type:      n.Type,
-					Role:      n.Role,
-					Content:   n.Content,
-					Model:     n.Model,
-					Provider:  n.Provider,
-					Timestamp: n.Timestamp,
-					Children:  n.Children,
-				}
-			}
-			return result
-		},
-		GetChildren: func(parentID string) []string {
-			return kitInstance.GetChildren(parentID)
-		},
-		NavigateTo: func(entryID string) extensions.TreeNavigationResult {
-			err := kitInstance.NavigateTo(entryID)
-			if err != nil {
-				return extensions.TreeNavigationResult{Success: false, Error: err.Error()}
-			}
-			return extensions.TreeNavigationResult{Success: true}
-		},
-		SummarizeBranch: func(fromID, toID string) string {
-			summary, _ := kitInstance.SummarizeBranch(fromID, toID)
-			return summary
-		},
-		CollapseBranch: func(fromID, toID, summary string) extensions.TreeNavigationResult {
-			err := kitInstance.CollapseBranch(fromID, toID, summary)
-			if err != nil {
-				return extensions.TreeNavigationResult{Success: false, Error: err.Error()}
-			}
-			return extensions.TreeNavigationResult{Success: true}
-		},
+	ec := extbridge.BaseContext(deps.ctx, kitInstance)
 
-		// -------------------------------------------------------------------
-		// Skill Loading API
-		// -------------------------------------------------------------------
-		LoadSkill: func(path string) (*extensions.Skill, string) {
-			s, err := kitInstance.LoadSkillForExtension(path)
-			return s, err
-		},
-		LoadSkillsFromDir: func(dir string) extensions.SkillLoadResult {
-			return kitInstance.LoadSkillsFromDirForExtension(dir)
-		},
-		DiscoverSkills: func() extensions.SkillLoadResult {
-			skills := kitInstance.DiscoverSkillsForExtension()
-			return extensions.SkillLoadResult{Skills: skills}
-		},
-		InjectSkillAsContext: func(skillName string) string {
-			skills := kitInstance.DiscoverSkillsForExtension()
-			for _, s := range skills {
-				if s.Name == skillName {
-					appInstance.Run(fmt.Sprintf("<skill name=%q>\n%s\n</skill>", s.Name, s.Content))
-					return ""
-				}
-			}
-			return fmt.Sprintf("skill not found: %s", skillName)
-		},
-		InjectRawSkillAsContext: func(path string) string {
-			s, err := kitInstance.LoadSkillForExtension(path)
-			if err != "" {
-				return err
-			}
-			appInstance.Run(fmt.Sprintf("<skill name=%q>\n%s\n</skill>", s.Name, s.Content))
-			return ""
-		},
-		GetAvailableSkills: func() []extensions.Skill {
-			return kitInstance.DiscoverSkillsForExtension()
-		},
+	ec.CWD = deps.cwd
+	ec.Model = deps.modelName
+	ec.Interactive = deps.interactive
 
-		// -------------------------------------------------------------------
-		// Template Parsing API
-		// -------------------------------------------------------------------
-		ParseTemplate: func(name, content string) extensions.PromptTemplate {
-			return kit.ParseTemplate(name, content)
-		},
-		RenderTemplate: func(tpl extensions.PromptTemplate, vars map[string]string) string {
-			return kit.RenderTemplate(tpl, vars)
-		},
-		ParseArguments: func(input string, pattern extensions.ArgumentPattern) extensions.ParseResult {
-			return kit.ParseArguments(input, pattern)
-		},
-		SimpleParseArguments: func(input string, count int) []string {
-			return kit.SimpleParseArguments(input, count)
-		},
-		EvaluateModelConditional: func(condition string) bool {
-			return kit.EvaluateModelConditional(kitInstance.Extensions().GetContext().Model, condition)
-		},
-		RenderWithModelConditionals: func(content string) string {
-			return kit.RenderWithModelConditionals(content, kitInstance.Extensions().GetContext().Model)
-		},
-
-		// -------------------------------------------------------------------
-		// Model Resolution API
-		// -------------------------------------------------------------------
-		ResolveModelChain: func(preferences []string) extensions.ModelResolutionResult {
-			return kit.ResolveModelChain(preferences)
-		},
-		GetModelCapabilities: func(model string) (extensions.ModelCapabilities, string) {
-			return kit.GetModelCapabilities(model)
-		},
-		CheckModelAvailable: func(model string) bool {
-			return kit.CheckModelAvailable(model)
-		},
-		GetCurrentProvider: func() string {
-			return kit.GetCurrentProvider(kitInstance.Extensions().GetContext().Model)
-		},
-		GetCurrentModelID: func() string {
-			return kit.GetCurrentModelID(kitInstance.Extensions().GetContext().Model)
-		},
+	ec.PrintBlock = func(opts extensions.PrintBlockOpts) {
+		appInstance.PrintBlockFromExtension(opts)
 	}
+	ec.SendMessage = func(text string) { appInstance.Run(text) }
+	ec.CancelAndSend = func(text string) { appInstance.InterruptAndSend(text) }
+	ec.Abort = func() { appInstance.Abort() }
+	ec.IsIdle = func() bool { return !appInstance.IsBusy() }
+	ec.Compact = func(cfg extensions.CompactConfig) error {
+		return appInstance.CompactAsync(cfg.CustomInstructions, cfg.OnComplete, cfg.OnError)
+	}
+	ec.SendMultimodalMessage = func(text string, files []extensions.FilePart) {
+		parts := make([]kit.LLMFilePart, len(files))
+		for i, f := range files {
+			parts[i] = kit.LLMFilePart{
+				Filename:  f.Filename,
+				Data:      f.Data,
+				MediaType: f.MediaType,
+			}
+		}
+		appInstance.RunWithFiles(text, parts)
+	}
+	ec.GetSessionUsage = func() extensions.SessionUsage {
+		if usageTracker == nil {
+			return extensions.SessionUsage{}
+		}
+		stats := usageTracker.GetSessionStats()
+		return extensions.SessionUsage{
+			TotalInputTokens:      stats.TotalInputTokens,
+			TotalOutputTokens:     stats.TotalOutputTokens,
+			TotalCacheReadTokens:  stats.TotalCacheReadTokens,
+			TotalCacheWriteTokens: stats.TotalCacheWriteTokens,
+			TotalCost:             stats.TotalCost,
+			RequestCount:          stats.RequestCount,
+		}
+	}
+	ec.Exit = func() { appInstance.QuitFromExtension() }
+
+	// TUI widgets/chrome — mutate runner state, then notify the TUI.
+	// Always use a goroutine for NotifyWidgetUpdate: prog.Send() deadlocks
+	// if called synchronously from inside BubbleTea's Update() handler.
+	// All call sites use go-routines uniformly.
+	ec.SetWidget = func(config extensions.WidgetConfig) {
+		kitInstance.Extensions().SetWidget(config)
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.RemoveWidget = func(id string) {
+		kitInstance.Extensions().RemoveWidget(id)
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.SetHeader = func(config extensions.HeaderFooterConfig) {
+		kitInstance.Extensions().SetHeader(config)
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.RemoveHeader = func() {
+		kitInstance.Extensions().RemoveHeader()
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.SetFooter = func(config extensions.HeaderFooterConfig) {
+		kitInstance.Extensions().SetFooter(config)
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.RemoveFooter = func() {
+		kitInstance.Extensions().RemoveFooter()
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.SetUIVisibility = func(v extensions.UIVisibility) {
+		kitInstance.Extensions().SetUIVisibility(v)
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.SetEditor = func(config extensions.EditorConfig) {
+		kitInstance.Extensions().SetEditor(config)
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.ResetEditor = func() {
+		kitInstance.Extensions().ResetEditor()
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.SetEditorText = func(text string) {
+		appInstance.SetEditorTextFromExtension(text)
+	}
+	ec.SetStatus = func(key string, text string, priority int) {
+		kitInstance.Extensions().SetStatus(extensions.StatusBarEntry{
+			Key:      key,
+			Text:     text,
+			Priority: priority,
+		})
+		go appInstance.NotifyWidgetUpdate()
+	}
+	ec.RemoveStatus = func(key string) {
+		kitInstance.Extensions().RemoveStatus(key)
+		go appInstance.NotifyWidgetUpdate()
+	}
+
+	// Interactive prompts — channel-based round trips through the TUI.
+	ec.PromptSelect = func(config extensions.PromptSelectConfig) extensions.PromptSelectResult {
+		ch := make(chan app.PromptResponse, 1)
+		appInstance.SendPromptRequest(app.PromptRequestEvent{
+			PromptType: "select",
+			Message:    config.Message,
+			Options:    config.Options,
+			ResponseCh: ch,
+		})
+		resp := <-ch
+		if resp.Cancelled {
+			return extensions.PromptSelectResult{Cancelled: true}
+		}
+		return extensions.PromptSelectResult{Value: resp.Value, Index: resp.Index}
+	}
+	ec.PromptConfirm = func(config extensions.PromptConfirmConfig) extensions.PromptConfirmResult {
+		ch := make(chan app.PromptResponse, 1)
+		def := "false"
+		if config.DefaultValue {
+			def = "true"
+		}
+		appInstance.SendPromptRequest(app.PromptRequestEvent{
+			PromptType: "confirm",
+			Message:    config.Message,
+			Default:    def,
+			ResponseCh: ch,
+		})
+		resp := <-ch
+		if resp.Cancelled {
+			return extensions.PromptConfirmResult{Cancelled: true}
+		}
+		return extensions.PromptConfirmResult{Value: resp.Confirmed}
+	}
+	ec.PromptInput = func(config extensions.PromptInputConfig) extensions.PromptInputResult {
+		ch := make(chan app.PromptResponse, 1)
+		appInstance.SendPromptRequest(app.PromptRequestEvent{
+			PromptType:  "input",
+			Message:     config.Message,
+			Placeholder: config.Placeholder,
+			Default:     config.Default,
+			ResponseCh:  ch,
+		})
+		resp := <-ch
+		if resp.Cancelled {
+			return extensions.PromptInputResult{Cancelled: true}
+		}
+		return extensions.PromptInputResult{Value: resp.Value}
+	}
+	ec.ShowOverlay = func(config extensions.OverlayConfig) extensions.OverlayResult {
+		ch := make(chan app.OverlayResponse, 1)
+		appInstance.SendOverlayRequest(app.OverlayRequestEvent{
+			Title:       config.Title,
+			Content:     config.Content.Text,
+			Markdown:    config.Content.Markdown,
+			BorderColor: config.Style.BorderColor,
+			Background:  config.Style.Background,
+			Width:       config.Width,
+			MaxHeight:   config.MaxHeight,
+			Anchor:      string(config.Anchor),
+			Actions:     config.Actions,
+			ResponseCh:  ch,
+		})
+		resp := <-ch
+		if resp.Cancelled {
+			return extensions.OverlayResult{Cancelled: true, Index: -1}
+		}
+		return extensions.OverlayResult{
+			Action: resp.Action,
+			Index:  resp.Index,
+		}
+	}
+	ec.SuspendTUI = func(callback func()) error {
+		return appInstance.SuspendTUI(callback)
+	}
+
+	// TUI-aware model switch: also notifies the TUI status bar and
+	// refreshes the usage tracker for correct token counting.
+	ec.SetModel = func(modelString string) error {
+		// Capture previous model for the ModelChange event.
+		previousModel := kitInstance.Extensions().GetContext().Model
+		err := kitInstance.SetModel(context.Background(), modelString)
+		if err != nil {
+			return err
+		}
+		// Notify TUI so it updates model in status bar.
+		p, m, _ := models.ParseModelString(modelString)
+		appInstance.NotifyModelChanged(p, m)
+		// Update the context's Model field so handlers see it.
+		kitInstance.Extensions().UpdateContextModel(modelString)
+		// Fire OnModelChange event to extensions.
+		kitInstance.Extensions().EmitModelChange(modelString, previousModel, "extension")
+		// Update usage tracker with new model info for correct token counting.
+		ui.UpdateUsageTrackerForModel(usageTracker, modelString, viper.GetString("provider-api-key"))
+		return nil
+	}
+
+	ec.RenderMessage = func(rendererName, content string) {
+		renderer := kitInstance.Extensions().GetMessageRenderer(rendererName)
+		if renderer == nil || renderer.Render == nil {
+			appInstance.PrintFromExtension("", content)
+			return
+		}
+		w, _, _ := term.GetSize(int(os.Stdout.Fd()))
+		if w == 0 {
+			w = 80
+		}
+		rendered := renderer.Render(content, w)
+		appInstance.PrintFromExtension("", rendered)
+	}
+	ec.ReloadExtensions = func() error {
+		err := kitInstance.Extensions().Reload()
+		if err != nil {
+			return err
+		}
+		// Notify TUI that widgets/status/commands may have changed.
+		go appInstance.NotifyWidgetUpdate()
+		return nil
+	}
+
+	// Theme management (TUI only).
+	ec.RegisterTheme = func(name string, config extensions.ThemeColorConfig) {
+		tc := func(c extensions.ThemeColor) [2]string { return [2]string{c.Light, c.Dark} }
+		ui.RegisterThemeFromConfig(name,
+			tc(config.Primary), tc(config.Secondary),
+			tc(config.Success), tc(config.Warning),
+			tc(config.Error), tc(config.Info),
+			tc(config.Text), tc(config.Muted),
+			tc(config.VeryMuted), tc(config.Background),
+			tc(config.Border), tc(config.MutedBorder),
+			tc(config.System), tc(config.Tool),
+			tc(config.Accent), tc(config.Highlight),
+			tc(config.MdHeading), tc(config.MdLink),
+			tc(config.MdKeyword), tc(config.MdString),
+			tc(config.MdNumber), tc(config.MdComment),
+		)
+	}
+	ec.SetTheme = func(name string) error {
+		return ui.ApplyTheme(name)
+	}
+	ec.ListThemes = func() []string {
+		return ui.ListThemes()
+	}
+
+	// Skill context-injection (drives a new agent turn through the TUI).
+	ec.InjectSkillAsContext = func(skillName string) string {
+		skills := kitInstance.DiscoverSkillsForExtension()
+		for _, s := range skills {
+			if s.Name == skillName {
+				appInstance.Run(fmt.Sprintf("<skill name=%q>\n%s\n</skill>", s.Name, s.Content))
+				return ""
+			}
+		}
+		return fmt.Sprintf("skill not found: %s", skillName)
+	}
+	ec.InjectRawSkillAsContext = func(path string) string {
+		s, err := kitInstance.LoadSkillForExtension(path)
+		if err != "" {
+			return err
+		}
+		appInstance.Run(fmt.Sprintf("<skill name=%q>\n%s\n</skill>", s.Name, s.Content))
+		return ""
+	}
+
+	return ec
 }

cmd/github.go

@@ -0,0 +1,255 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"charm.land/huh/v2"
+	"github.com/charmbracelet/log"
+	kit "github.com/mark3labs/kit/pkg/kit"
+	"github.com/spf13/cobra"
+)
+
+// defaultGitHubModel is the model written into the generated workflow when the
+// user does not specify one and runs non-interactively.
+const defaultGitHubModel = "anthropic/claude-sonnet-4-5-20250929"
+
+// githubWorkflowPath is the repository-relative location of the generated
+// GitHub Actions workflow that wires Kit into a repository as a collaborator.
+const githubWorkflowPath = ".github/workflows/kit.yml"
+
+var (
+	githubInstallModel    string
+	githubInstallForce    bool
+	githubInstallNoSecret bool
+)
+
+// githubCmd is the parent command for GitHub integration subcommands. It groups
+// the turnkey setup tooling that wires Kit into a repository as an automated
+// collaborator/reviewer driven by GitHub Actions.
+var githubCmd = &cobra.Command{
+	Use:   "github",
+	Short: "Set up Kit as a GitHub collaborator/reviewer",
+	Long: `Set up Kit as an automated collaborator/reviewer in a GitHub repository.
+
+Kit runs inside a GitHub Actions runner, reads the relevant context (an issue
+thread or pull request), runs the agent non-interactively, and responds by
+posting comments and opening pull requests.
+
+Use 'kit github install' to scaffold the GitHub Actions workflow.`,
+}
+
+// githubInstallCmd scaffolds the GitHub Actions workflow that runs Kit on
+// '/kit' comment triggers. It writes .github/workflows/kit.yml and, when the
+// 'gh' CLI is available, offers to set the provider API key as a repository
+// secret.
+var githubInstallCmd = &cobra.Command{
+	Use:   "install",
+	Short: "Scaffold the GitHub Actions workflow that runs Kit",
+	Long: `Scaffold the GitHub Actions workflow that runs Kit as a collaborator.
+
+This writes .github/workflows/kit.yml configured to trigger when someone
+comments '/kit ...' on an issue or pull request review. The workflow runs Kit
+inside an ephemeral Actions runner with least-privilege permissions and
+'persist-credentials: false', mirroring established security practice.
+
+If the GitHub CLI ('gh') is detected on your PATH, you will be offered the
+option to store your provider API key as a repository secret automatically.
+
+Flags:
+  --model       Provider/model to write into the workflow (e.g. anthropic/claude-sonnet-4-5)
+  --force       Overwrite an existing workflow file
+  --no-secret   Skip the offer to set the provider secret via the gh CLI
+
+Examples:
+  kit github install
+  kit github install --model anthropic/claude-sonnet-4-5-20250929
+  kit github install --force --no-secret`,
+	Args: cobra.NoArgs,
+	RunE: runGitHubInstall,
+}
+
+func init() {
+	githubInstallCmd.Flags().StringVarP(&githubInstallModel, "model", "m", "", "provider/model to write into the workflow")
+	githubInstallCmd.Flags().BoolVar(&githubInstallForce, "force", false, "overwrite an existing workflow file")
+	githubInstallCmd.Flags().BoolVar(&githubInstallNoSecret, "no-secret", false, "skip setting the provider secret via the gh CLI")
+
+	githubCmd.AddCommand(githubInstallCmd)
+	rootCmd.AddCommand(githubCmd)
+}
+
+func runGitHubInstall(cmd *cobra.Command, _ []string) error {
+	model, err := resolveGitHubModel()
+	if err != nil {
+		return err
+	}
+
+	provider, _, err := kit.ParseModelString(model)
+	if err != nil {
+		return fmt.Errorf("invalid model %q: %w", model, err)
+	}
+
+	secretName := providerSecretEnvVar(provider)
+
+	if err := writeGitHubWorkflow(model, secretName, githubInstallForce); err != nil {
+		return err
+	}
+	fmt.Printf("✅ Wrote %s\n", githubWorkflowPath)
+
+	maybeSetProviderSecret(cmd.Context(), secretName)
+
+	printGitHubInstallNextSteps(secretName)
+	log.Info("github workflow scaffolded", "model", model, "secret", secretName)
+	return nil
+}
+
+// resolveGitHubModel determines the model to embed in the workflow. The
+// --model flag takes precedence; otherwise an interactive prompt is shown
+// (pre-filled with the default), and non-interactive runs use the default.
+func resolveGitHubModel() (string, error) {
+	if githubInstallModel != "" {
+		return strings.TrimSpace(githubInstallModel), nil
+	}
+
+	if !isInteractive() {
+		return defaultGitHubModel, nil
+	}
+
+	model := defaultGitHubModel
+	err := huh.NewInput().
+		Title("Model").
+		Description("Provider/model Kit should use in CI (e.g. anthropic/claude-sonnet-4-5)").
+		Value(&model).
+		Run()
+	if err != nil {
+		return "", fmt.Errorf("model selection cancelled: %w", err)
+	}
+
+	model = strings.TrimSpace(model)
+	if model == "" {
+		return "", fmt.Errorf("model cannot be empty")
+	}
+	return model, nil
+}
+
+// providerSecretEnvVar returns the environment variable / repository secret
+// name that holds the API key for the given provider. It consults the model
+// registry and falls back to "<PROVIDER>_API_KEY" for unknown providers.
+func providerSecretEnvVar(provider string) string {
+	if info := kit.GetProviderInfo(provider); info != nil && len(info.Env) > 0 {
+		return info.Env[0]
+	}
+	sanitized := strings.ToUpper(strings.NewReplacer("-", "_", ".", "_").Replace(provider))
+	return sanitized + "_API_KEY"
+}
+
+// renderGitHubWorkflow builds the workflow YAML for the given model and
+// provider secret name.
+func renderGitHubWorkflow(model, secretName string) string {
+	return fmt.Sprintf(`name: kit
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+jobs:
+  kit:
+    if: |
+      (github.event.comment.author_association == 'OWNER' ||
+       github.event.comment.author_association == 'MEMBER' ||
+       github.event.comment.author_association == 'COLLABORATOR') &&
+      (startsWith(github.event.comment.body, '/kit ') ||
+       github.event.comment.body == '/kit')
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+      issues: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - uses: mark3labs/kit-action@v1
+        with:
+          model: %s
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          %s: ${{ secrets.%s }}
+`, model, secretName, secretName)
+}
+
+// writeGitHubWorkflow writes the generated workflow to githubWorkflowPath,
+// creating parent directories as needed. It refuses to overwrite an existing
+// file unless force is true.
+func writeGitHubWorkflow(model, secretName string, force bool) error {
+	if _, err := os.Stat(githubWorkflowPath); err == nil && !force {
+		return fmt.Errorf("%s already exists; re-run with --force to overwrite", githubWorkflowPath)
+	} else if err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("checking %s: %w", githubWorkflowPath, err)
+	}
+
+	if err := os.MkdirAll(filepath.Dir(githubWorkflowPath), 0o755); err != nil {
+		return fmt.Errorf("creating %s: %w", filepath.Dir(githubWorkflowPath), err)
+	}
+
+	content := renderGitHubWorkflow(model, secretName)
+	if err := os.WriteFile(githubWorkflowPath, []byte(content), 0o644); err != nil {
+		return fmt.Errorf("writing %s: %w", githubWorkflowPath, err)
+	}
+	return nil
+}
+
+// maybeSetProviderSecret offers to set the provider API key as a repository
+// secret via the gh CLI when it is available, interactive, the secret value is
+// present in the environment, and the user did not pass --no-secret.
+func maybeSetProviderSecret(ctx context.Context, secretName string) {
+	if githubInstallNoSecret || !isInteractive() {
+		return
+	}
+
+	if _, err := exec.LookPath("gh"); err != nil {
+		return
+	}
+
+	value := os.Getenv(secretName)
+	if value == "" {
+		fmt.Printf("ℹ️  %s is not set in your environment; set the repository secret manually with:\n", secretName)
+		fmt.Printf("     gh secret set %s\n", secretName)
+		return
+	}
+
+	var confirm bool
+	if err := huh.NewConfirm().
+		Title(fmt.Sprintf("Set the %s repository secret via gh?", secretName)).
+		Description("Uses the value from your current environment.").
+		Value(&confirm).
+		Run(); err != nil || !confirm {
+		return
+	}
+
+	// Feed the secret value via stdin rather than a command-line argument so
+	// the API key never appears in the process argument list.
+	cmd := exec.CommandContext(ctx, "gh", "secret", "set", secretName)
+	cmd.Stdin = strings.NewReader(value)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		fmt.Printf("⚠️  Failed to set secret via gh: %v\n", err)
+		fmt.Printf("     Set it manually with: gh secret set %s\n", secretName)
+		return
+	}
+	fmt.Printf("✅ Set repository secret %s\n", secretName)
+}
+
+// printGitHubInstallNextSteps prints the manual follow-up actions a user must
+// take after the workflow is scaffolded.
+func printGitHubInstallNextSteps(secretName string) {
+	fmt.Println("\nNext steps:")
+	fmt.Printf("  1. Commit the workflow:  git add %s && git commit -m \"ci: add kit workflow\"\n", githubWorkflowPath)
+	fmt.Printf("  2. Set the %s repository secret (Settings → Secrets → Actions), if not already set.\n", secretName)
+	fmt.Println("  3. Comment '/kit <your request>' on an issue or pull request to trigger Kit.")
+}

cmd/github_test.go

@@ -0,0 +1,102 @@
+package cmd
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestProviderSecretEnvVar(t *testing.T) {
+	tests := []struct {
+		provider string
+		want     string
+	}{
+		{"anthropic", "ANTHROPIC_API_KEY"},
+		{"openai", "OPENAI_API_KEY"},
+		// Unknown provider falls back to "<PROVIDER>_API_KEY" with sanitization.
+		{"my-custom.provider", "MY_CUSTOM_PROVIDER_API_KEY"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.provider, func(t *testing.T) {
+			got := providerSecretEnvVar(tt.provider)
+			if got != tt.want {
+				t.Errorf("providerSecretEnvVar(%q) = %q, want %q", tt.provider, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRenderGitHubWorkflow(t *testing.T) {
+	out := renderGitHubWorkflow("anthropic/claude-sonnet-4-5-20250929", "ANTHROPIC_API_KEY")
+
+	wantSubstrings := []string{
+		"name: kit",
+		"issue_comment:",
+		"pull_request_review_comment:",
+		"startsWith(github.event.comment.body, '/kit ')",
+		"github.event.comment.body == '/kit'",
+		"github.event.comment.author_association == 'OWNER'",
+		"github.event.comment.author_association == 'COLLABORATOR'",
+		"persist-credentials: false",
+		"uses: mark3labs/kit-action@v1",
+		"model: anthropic/claude-sonnet-4-5-20250929",
+		"GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}",
+		"ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}",
+		"contents: write",
+		"pull-requests: write",
+		"issues: write",
+	}
+	for _, want := range wantSubstrings {
+		if !strings.Contains(out, want) {
+			t.Errorf("rendered workflow missing %q\n---\n%s", want, out)
+		}
+	}
+}
+
+func TestWriteGitHubWorkflow(t *testing.T) {
+	dir := t.TempDir()
+	cwd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = os.Chdir(cwd) })
+	if err := os.Chdir(dir); err != nil {
+		t.Fatal(err)
+	}
+
+	// First write succeeds and creates nested directories.
+	if err := writeGitHubWorkflow("anthropic/claude-sonnet-4-5", "ANTHROPIC_API_KEY", false); err != nil {
+		t.Fatalf("writeGitHubWorkflow: %v", err)
+	}
+	data, err := os.ReadFile(githubWorkflowPath)
+	if err != nil {
+		t.Fatalf("reading workflow: %v", err)
+	}
+	if !strings.Contains(string(data), "model: anthropic/claude-sonnet-4-5") {
+		t.Errorf("workflow missing model line:\n%s", data)
+	}
+
+	// Second write without force must refuse to clobber.
+	if err := writeGitHubWorkflow("anthropic/claude-sonnet-4-5", "ANTHROPIC_API_KEY", false); err == nil {
+		t.Error("expected error when overwriting without --force, got nil")
+	}
+
+	// With force it overwrites.
+	if err := writeGitHubWorkflow("openai/gpt-5", "OPENAI_API_KEY", true); err != nil {
+		t.Fatalf("writeGitHubWorkflow with force: %v", err)
+	}
+	data, err = os.ReadFile(githubWorkflowPath)
+	if err != nil {
+		t.Fatalf("reading workflow: %v", err)
+	}
+	if !strings.Contains(string(data), "OPENAI_API_KEY") {
+		t.Errorf("forced overwrite did not update content:\n%s", data)
+	}
+
+	// Sanity: the file lives at the expected nested path.
+	if _, err := os.Stat(filepath.Join(dir, githubWorkflowPath)); err != nil {
+		t.Errorf("workflow not at expected path: %v", err)
+	}
+}

cmd/root.go

@@ -12,7 +12,6 @@ import (
 
 	tea "charm.land/bubbletea/v2"
 	"github.com/mark3labs/kit/internal/app"
-	"github.com/mark3labs/kit/internal/auth"
 	"github.com/mark3labs/kit/internal/config"
 	"github.com/mark3labs/kit/internal/extensions"
 	"github.com/mark3labs/kit/internal/models"
@@ -74,6 +73,11 @@ var (
 	noCoreToolsFlag  bool
 	extensionPaths   []string
 
+	// Skills control
+	noSkillsFlag bool
+	skillsPaths  []string
+	skillsDir    string
+
 	// TLS configuration
 	tlsSkipVerify bool
 
@@ -284,6 +288,14 @@ func init() {
 	rootCmd.PersistentFlags().
 		StringSliceVarP(&extensionPaths, "extension", "e", nil, "load additional extension file(s)")
 
+	// Skills flags
+	rootCmd.PersistentFlags().
+		BoolVar(&noSkillsFlag, "no-skills", false, "disable skill loading (auto-discovery and explicit)")
+	rootCmd.PersistentFlags().
+		StringSliceVar(&skillsPaths, "skill", nil, "load skill file or directory (repeatable)")
+	rootCmd.PersistentFlags().
+		StringVar(&skillsDir, "skills-dir", "", "override the project-local skills directory for auto-discovery")
+
 	flags := rootCmd.PersistentFlags()
 	flags.StringVar(&providerURL, "provider-url", "", "base URL for the provider API (applies to OpenAI, Anthropic, Ollama, and Google)")
 	flags.StringVar(&providerAPIKey, "provider-api-key", "", "API key for the provider (applies to OpenAI, Anthropic, and Google)")
@@ -334,6 +346,9 @@ func init() {
 	_ = viper.BindPFlag("extension", rootCmd.PersistentFlags().Lookup("extension"))
 	_ = viper.BindPFlag("prompt-template", rootCmd.PersistentFlags().Lookup("prompt-template"))
 	_ = viper.BindPFlag("no-prompt-templates", rootCmd.PersistentFlags().Lookup("no-prompt-templates"))
+	_ = viper.BindPFlag("no-skills", rootCmd.PersistentFlags().Lookup("no-skills"))
+	_ = viper.BindPFlag("skill", rootCmd.PersistentFlags().Lookup("skill"))
+	_ = viper.BindPFlag("skills-dir", rootCmd.PersistentFlags().Lookup("skills-dir"))
 
 	// Defaults are already set in flag definitions, no need to duplicate in viper
 
@@ -677,8 +692,8 @@ func globalShortcutsProviderForUI(k *kit.Kit) func() map[string]func() {
 	}
 }
 
-func runNormalMode(ctx context.Context) error {
-	// Validate flag combinations
+// validateModeFlags rejects invalid flag combinations for the root command.
+func validateModeFlags() error {
 	if quietFlag && positionalPrompt == "" {
 		return fmt.Errorf("--quiet requires a prompt (e.g. kit \"your question\" --quiet)")
 	}
@@ -691,21 +706,14 @@ func runNormalMode(ctx context.Context) error {
 	if noExitFlag && positionalPrompt == "" {
 		return fmt.Errorf("--no-exit requires a prompt (e.g. kit \"your question\" --no-exit)")
 	}
+	return nil
+}
 
-	// Set up logging
-	if debugMode {
-		log.SetFlags(log.LstdFlags | log.Lshortfile)
-	}
-
-	// Update debug mode from viper
-	if viper.GetBool("debug") && !debugMode {
-		debugMode = viper.GetBool("debug")
-		log.SetFlags(log.LstdFlags | log.Lshortfile)
-	}
-
-	// Restore persisted model preference when no explicit --model flag or
-	// config file model is set. Precedence: CLI flag > config file > saved
-	// preference > built-in default. This mirrors how themes are persisted.
+// restorePersistedPreferences applies saved model / thinking-level
+// preferences into viper when neither a CLI flag nor a config-file value
+// takes precedence. Precedence: CLI flag > config file > saved preference >
+// built-in default. This mirrors how themes are persisted.
+func restorePersistedPreferences() {
 	// Skip custom/* models unless --provider-url is also provided, since the
 	// custom provider requires a URL that was only valid for the previous session.
 	if !modelFlagChanged && !viper.InConfig("model") {
@@ -724,6 +732,15 @@ func runNormalMode(ctx context.Context) error {
 			viper.Set("thinking-level", pref)
 		}
 	}
+}
+
+// applyProviderURLRouting rewrites the model in viper when --provider-url
+// is set, routing requests through the "custom" (OpenAI-compatible)
+// provider. Must run after restorePersistedPreferences.
+func applyProviderURLRouting() {
+	if viper.GetString("provider-url") == "" {
+		return
+	}
 
 	// When --provider-url is set but no explicit --model was provided,
 	// default to "custom/custom" so the user doesn't need to remember a
@@ -731,7 +748,7 @@ func runNormalMode(ctx context.Context) error {
 	// This intentionally overrides saved preferences but respects config-file
 	// models — if you specify a model in ~/.kit.yml, it will be used with
 	// custom/custom's provider routing.
-	if viper.GetString("provider-url") != "" && !modelFlagChanged && !viper.InConfig("model") {
+	if !modelFlagChanged && !viper.InConfig("model") {
 		viper.Set("model", "custom/custom")
 	}
 
@@ -746,7 +763,7 @@ func runNormalMode(ctx context.Context) error {
 	// to point a non-OpenAI wire (Anthropic, Google, ...) at a proxy URL,
 	// use the explicit `custom/<name>` form to opt out of the rewrite by
 	// configuring the proxy as that provider in your config file instead.
-	if viper.GetString("provider-url") != "" && modelFlagChanged {
+	if modelFlagChanged {
 		model := viper.GetString("model")
 		if model != "" {
 			name := model
@@ -758,6 +775,26 @@ func runNormalMode(ctx context.Context) error {
 			}
 		}
 	}
+}
+
+func runNormalMode(ctx context.Context) error {
+	if err := validateModeFlags(); err != nil {
+		return err
+	}
+
+	// Set up logging
+	if debugMode {
+		log.SetFlags(log.LstdFlags | log.Lshortfile)
+	}
+
+	// Update debug mode from viper
+	if viper.GetBool("debug") && !debugMode {
+		debugMode = viper.GetBool("debug")
+		log.SetFlags(log.LstdFlags | log.Lshortfile)
+	}
+
+	restorePersistedPreferences()
+	applyProviderURLRouting()
 
 	// Load MCP configuration.
 	mcpConfig, err := config.LoadAndValidateConfig()
@@ -799,6 +836,9 @@ func runNormalMode(ctx context.Context) error {
 		AutoCompact:      autoCompactFlag,
 		MCPAuthHandler:   authHandler,
 		DisableCoreTools: viper.GetBool("no-core-tools"),
+		NoSkills:         noSkillsFlag,
+		Skills:           skillsPaths,
+		SkillsDir:        skillsDir,
 		// This callback is called when each MCP server finishes loading.
 		// We use a closure that captures appInstancePtr which is set after
 		// app.New() is called below.
@@ -1164,23 +1204,7 @@ func runNormalMode(ctx context.Context) error {
 		// NotifyModelChanged calls prog.Send() which deadlocks. The UI layer
 		// updates m.providerName and m.modelName directly after setModel returns.
 		// Update usage tracker with new model info for correct token counting.
-		if usageTracker != nil {
-			newProvider, newModel, _ := models.ParseModelString(modelString)
-			if newProvider != "unknown" && newModel != "unknown" && newProvider != "ollama" {
-				registry := models.GetGlobalRegistry()
-				if modelInfo := registry.LookupModel(newProvider, newModel); modelInfo != nil {
-					// Check OAuth status for Anthropic models
-					isOAuth := false
-					if newProvider == "anthropic" {
-						_, source, err := auth.GetAnthropicAPIKey(viper.GetString("provider-api-key"))
-						if err == nil && strings.HasPrefix(source, "stored OAuth") {
-							isOAuth = true
-						}
-					}
-					usageTracker.UpdateModelInfo(modelInfo, newProvider, isOAuth)
-				}
-			}
-		}
+		ui.UpdateUsageTrackerForModel(usageTracker, modelString, viper.GetString("provider-api-key"))
 		return nil
 	}
 	emitModelChangeForUI := func(newModel, previousModel, source string) {

examples/extensions/README.md

@@ -83,6 +83,7 @@ kit install github.com/mark3labs/kit/examples/extensions --local
 | Extension | Description | Key API |
 |-----------|-------------|---------|
 | `kit-telegram/` | Telegram relay for remote monitoring & control | `RegisterCommand`, `OnAgentStart/End`, `SetStatus`, `SendMessage` |
+| `github-handler/` | Run Kit as a GitHub collaborator inside Actions (`/kit` comments → reviews & PRs) | `OnSessionStart`, `OnAgentEnd`, `SendMessage`, `RegisterOption` |
 
 ### Themes
 
@@ -146,6 +147,15 @@ Full-featured Telegram integration:
 - Status bar and widget updates
 - Config persistence with atomic writes
 
+### github-handler/
+Run Kit as a GitHub collaborator inside GitHub Actions:
+- Parses the triggering event from `GITHUB_EVENT_PATH`
+- Permission gate on `author_association` (write/admin only)
+- 👀 reaction lifecycle on the trigger comment
+- Issue-thread / PR-diff context extraction via `gh`
+- Drives the agent, posts the response, and opens a PR for any changes
+- `KIT_GITHUB_DRY_RUN` mode for safe, deterministic testing
+
 ## Multi-File Extension Example
 
 The `kit-kit-agents/` directory demonstrates the multi-file pattern:

examples/extensions/github-handler/README.md

@@ -0,0 +1,75 @@
+# GitHub Handler Extension
+
+The GitHub handler is the runtime half of Kit's GitHub integration (issue
+[#60](https://github.com/mark3labs/kit/issues/60), Phase 2b). It is designed to
+run **inside a GitHub Actions runner**, driven by the workflow that
+`kit github install` scaffolds.
+
+When a collaborator comments `/kit <request>` on an issue or pull request, the
+workflow boots Kit headlessly with this extension loaded. The extension then:
+
+1. **Parses** the triggering event from `GITHUB_EVENT_PATH`.
+2. **Enforces permissions** — only comments whose `author_association` is
+   `OWNER`, `MEMBER`, or `COLLABORATOR` are acted on.
+3. **Reacts** with 👀 on the trigger comment so the human knows Kit is working.
+4. **Gathers context** — the issue thread, or the pull request diff and
+   comments (via the `gh` CLI).
+5. **Drives the agent** with the request plus context.
+6. **Posts the response** back as a comment, and — if the agent left
+   uncommitted changes — pushes a branch as the `kit-agent[bot]` identity and
+   opens a pull request.
+7. **Swaps the reaction** to 🚀 (or 😕 on error) when finished.
+
+Outside of GitHub Actions (i.e. when `GITHUB_ACTIONS != "true"`) the extension
+is inert, so it is safe to keep loaded during normal local use.
+
+## Requirements
+
+- The [`gh` CLI](https://cli.github.com/) on `PATH`, authenticated via
+  `GITHUB_TOKEN` (GitHub Actions provides this automatically).
+- `git` on `PATH` with push access for opening pull requests.
+- A provider API key for the model Kit runs (e.g. `ANTHROPIC_API_KEY`).
+
+## Usage in a workflow
+
+`kit github install` writes `.github/workflows/kit.yml`. To wire in this
+handler, load it when invoking Kit headlessly inside the action, for example:
+
+```bash
+kit --quiet --no-session \
+  -e path/to/github-handler/main.go \
+  --model "$KIT_MODEL"
+```
+
+The extension reads the GitHub event itself, so no prompt argument is required —
+it constructs the prompt from the comment and repository context and drives the
+agent via the session lifecycle.
+
+## Environment variables
+
+| Variable             | Purpose                                                        |
+|----------------------|---------------------------------------------------------------|
+| `GITHUB_ACTIONS`     | Must be `true` for the handler to activate.                    |
+| `GITHUB_EVENT_PATH`  | Path to the JSON event payload (set by Actions).              |
+| `GITHUB_TOKEN`       | Used by `gh`/`git` for API and push operations.               |
+| `KIT_GITHUB_DRY_RUN` | When set, log `gh`/`git` side effects instead of running them. |
+
+## Options
+
+| Option            | Default | Description                                          |
+|-------------------|---------|------------------------------------------------------|
+| `github.dry-run`  | `false` | Log GitHub/git side effects instead of executing.    |
+
+## Dry-run mode
+
+Set `KIT_GITHUB_DRY_RUN=1` (or the `github.dry-run` option) to exercise the
+parsing, permission, and prompt-building logic without touching the network or
+the working tree. Every `gh`/`git` mutation is printed instead of executed.
+This is what the unit tests (`main_test.go`) use to stay deterministic.
+
+## Security
+
+- Triggers are gated to write/admin collaborators only.
+- The workflow uses `persist-credentials: false` and least-privilege
+  `permissions`, mirroring established practice.
+- Commits are attributed to a dedicated `kit-agent[bot]` identity.

examples/extensions/github-handler/main.go

@@ -0,0 +1,483 @@
+//go:build ignore
+
+// Package main implements the Kit GitHub handler extension.
+//
+// This is the Phase 2b "GitHub handler" piece of Kit's GitHub integration
+// (issue #60). It is designed to run *inside a GitHub Actions runner*, driven
+// by the workflow scaffolded by `kit github install`. When a collaborator
+// comments `/kit <request>` on an issue or pull request, the workflow boots Kit
+// headlessly with this extension loaded; the extension then:
+//
+//   - parses the triggering GitHub event from GITHUB_EVENT_PATH,
+//   - enforces that the comment author has write/admin access
+//     (author_association in OWNER / MEMBER / COLLABORATOR),
+//   - reacts with 👀 on the trigger comment while it works,
+//   - gathers context (issue thread or PR diff) and drives the agent with it,
+//   - posts the agent's response back as a comment, and
+//   - if the agent left uncommitted changes, pushes a branch as the
+//     `kit-agent[bot]` identity and opens a pull request.
+//
+// Outside of GitHub Actions (i.e. when GITHUB_ACTIONS != "true") the extension
+// is inert, so it is safe to keep loaded during normal local use.
+//
+// Set KIT_GITHUB_DRY_RUN=1 (or the `github.dry-run` option) to exercise the
+// parsing / permission / prompt-building logic without shelling out to `gh` or
+// `git` — every side effect is logged instead of executed. This is what the
+// unit tests use.
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+
+	"kit/ext"
+)
+
+// commandToken is the mention that triggers Kit from a comment, mirroring the
+// `if:` guard in the generated workflow (.github/workflows/kit.yml).
+const commandToken = "/kit"
+
+// subprocessTimeout bounds each git/gh invocation so a stalled network call or
+// an unexpected auth prompt cannot hang the Actions job indefinitely.
+const subprocessTimeout = 30 * time.Second
+
+// botName / botEmail are the dedicated identity commits are attributed to, so
+// Kit's changes are clearly distinguishable from human authors in history.
+const (
+	botName  = "kit-agent[bot]"
+	botEmail = "kit-agent[bot]@users.noreply.github.com"
+)
+
+// writeAssociations are the GitHub author_association values that imply
+// write/admin access. Only these may trigger the handler.
+var writeAssociations = map[string]bool{
+	"OWNER":        true,
+	"MEMBER":       true,
+	"COLLABORATOR": true,
+}
+
+// ghUser is a GitHub user as embedded in event payloads.
+type ghUser struct {
+	Login string `json:"login"`
+}
+
+// ghComment is the triggering comment.
+type ghComment struct {
+	ID                int64  `json:"id"`
+	Body              string `json:"body"`
+	AuthorAssociation string `json:"author_association"`
+	User              ghUser `json:"user"`
+}
+
+// ghIssue is the issue (or PR, since GitHub models PRs as issues) the comment
+// was posted on. PullRequest is non-nil when the issue is actually a PR.
+type ghIssue struct {
+	Number      int             `json:"number"`
+	Title       string          `json:"title"`
+	Body        string          `json:"body"`
+	PullRequest json.RawMessage `json:"pull_request"`
+}
+
+// ghPull is the pull request for pull_request_review_comment events.
+type ghPull struct {
+	Number int    `json:"number"`
+	Title  string `json:"title"`
+	Body   string `json:"body"`
+}
+
+// ghRepo identifies the repository the event originated from.
+type ghRepo struct {
+	FullName      string `json:"full_name"`
+	DefaultBranch string `json:"default_branch"`
+}
+
+// ghEvent is the subset of the GitHub Actions event payload the handler reads.
+type ghEvent struct {
+	Action      string     `json:"action"`
+	Comment     *ghComment `json:"comment"`
+	Issue       *ghIssue   `json:"issue"`
+	PullRequest *ghPull    `json:"pull_request"`
+	Repository  ghRepo     `json:"repository"`
+}
+
+// trigger captures everything the handler needs about a single invocation,
+// normalised across issue_comment and pull_request_review_comment events.
+type trigger struct {
+	repo          string
+	defaultBranch string
+	number        int    // issue or PR number
+	isPR          bool   // true when the target is a pull request
+	commentID     int64  // triggering comment id (for reactions)
+	commentKind   string // "issues" or "pulls" — reaction API path segment
+	author        string
+	association   string
+	request       string // the user's instruction (comment body minus the token)
+	title         string
+	body          string
+}
+
+func Init(api ext.API) {
+	api.RegisterOption(ext.OptionDef{
+		Name:        "github.dry-run",
+		Description: "Log GitHub/git side effects instead of executing them",
+		Default:     "false",
+	})
+
+	api.OnSessionStart(func(_ ext.SessionStartEvent, ctx ext.Context) {
+		if !inGitHubActions() {
+			return
+		}
+		handleSessionStart(ctx)
+	})
+
+	api.OnAgentEnd(func(e ext.AgentEndEvent, ctx ext.Context) {
+		if !inGitHubActions() || activeTrigger == nil {
+			return
+		}
+		handleAgentEnd(e, ctx)
+	})
+}
+
+// activeTrigger holds the parsed trigger between OnSessionStart and OnAgentEnd.
+// Yaegi supports package-level state captured by the handler closures.
+var activeTrigger *trigger
+
+func inGitHubActions() bool {
+	return os.Getenv("GITHUB_ACTIONS") == "true"
+}
+
+// dryRun reports whether side effects should be logged instead of executed.
+func dryRun(ctx ext.Context) bool {
+	if os.Getenv("KIT_GITHUB_DRY_RUN") != "" {
+		return true
+	}
+	return strings.EqualFold(ctx.GetOption("github.dry-run"), "true")
+}
+
+// handleSessionStart parses the event, enforces permissions, reacts on the
+// trigger comment, builds the prompt, and drives the agent.
+func handleSessionStart(ctx ext.Context) {
+	event, err := loadEvent()
+	if err != nil {
+		ctx.PrintError("kit-github: " + err.Error())
+		ctx.Exit()
+		return
+	}
+
+	tr, err := buildTrigger(event)
+	if err != nil {
+		// Not an actionable trigger (e.g. a comment without /kit). Stay quiet
+		// and let the run finish; the workflow `if:` normally prevents this.
+		ctx.PrintInfo("kit-github: " + err.Error())
+		ctx.Exit()
+		return
+	}
+
+	if !writeAssociations[strings.ToUpper(tr.association)] {
+		ctx.PrintError(fmt.Sprintf(
+			"kit-github: ignoring /kit from @%s — author_association %q lacks write access",
+			tr.author, tr.association))
+		ctx.Exit()
+		return
+	}
+
+	activeTrigger = tr
+
+	// React with 👀 so the human sees Kit picked up the request.
+	addReaction(ctx, tr, "eyes")
+
+	context := gatherContext(ctx, tr)
+	prompt := buildPrompt(tr, context)
+	ctx.SendMessage(prompt)
+}
+
+// loadEvent reads and decodes the GitHub Actions event payload.
+func loadEvent() (*ghEvent, error) {
+	path := os.Getenv("GITHUB_EVENT_PATH")
+	if path == "" {
+		return nil, fmt.Errorf("GITHUB_EVENT_PATH is not set")
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("reading event payload: %w", err)
+	}
+	var event ghEvent
+	if err := json.Unmarshal(data, &event); err != nil {
+		return nil, fmt.Errorf("parsing event payload: %w", err)
+	}
+	return &event, nil
+}
+
+// buildTrigger normalises an event into a trigger, or returns an error when the
+// event is not an actionable `/kit` comment.
+func buildTrigger(event *ghEvent) (*trigger, error) {
+	if event.Comment == nil {
+		return nil, fmt.Errorf("event has no comment; nothing to do")
+	}
+
+	request, ok := extractRequest(event.Comment.Body)
+	if !ok {
+		return nil, fmt.Errorf("comment does not contain the %q command", commandToken)
+	}
+
+	tr := &trigger{
+		repo:          event.Repository.FullName,
+		defaultBranch: event.Repository.DefaultBranch,
+		commentID:     event.Comment.ID,
+		author:        event.Comment.User.Login,
+		association:   event.Comment.AuthorAssociation,
+		request:       request,
+	}
+	if tr.defaultBranch == "" {
+		tr.defaultBranch = "main"
+	}
+
+	switch {
+	case event.Issue != nil:
+		tr.number = event.Issue.Number
+		tr.title = event.Issue.Title
+		tr.body = event.Issue.Body
+		tr.isPR = len(event.Issue.PullRequest) > 0
+		// issue_comment fires for both issues and PRs; reactions for PR
+		// comments posted on the conversation tab still use the issues path.
+		tr.commentKind = "issues"
+	case event.PullRequest != nil:
+		tr.number = event.PullRequest.Number
+		tr.title = event.PullRequest.Title
+		tr.body = event.PullRequest.Body
+		tr.isPR = true
+		// pull_request_review_comment reactions use the pulls path.
+		tr.commentKind = "pulls"
+	default:
+		return nil, fmt.Errorf("event has no issue or pull_request target")
+	}
+
+	if tr.repo == "" {
+		return nil, fmt.Errorf("event is missing repository.full_name")
+	}
+	return tr, nil
+}
+
+// extractRequest pulls the instruction text out of a comment body that mentions
+// the command token. It only recognizes the token at the start of a line
+// (mirroring the workflow guard) or at the very end, so incidental mid-sentence
+// mentions like "please review /kit behavior" do not trigger the handler. It
+// returns the remainder of the matching line as the request.
+func extractRequest(body string) (string, bool) {
+	for _, line := range strings.Split(body, "\n") {
+		trimmed := strings.TrimSpace(line)
+		var rest string
+		switch {
+		case trimmed == commandToken:
+			return "", true
+		case strings.HasPrefix(trimmed, commandToken+" "):
+			rest = trimmed[len(commandToken):]
+		case strings.HasSuffix(trimmed, " "+commandToken):
+			return "", true
+		default:
+			continue
+		}
+		return strings.TrimSpace(rest), true
+	}
+	return "", false
+}
+
+// gatherContext assembles the issue thread or PR diff to give the agent. It
+// always includes the title/body from the event payload, and — outside dry-run,
+// when `gh` is available — enriches with the full comment thread and PR diff.
+func gatherContext(ctx ext.Context, tr *trigger) string {
+	var b strings.Builder
+	target := "Issue"
+	if tr.isPR {
+		target = "Pull request"
+	}
+	fmt.Fprintf(&b, "%s #%d: %s\n", target, tr.number, tr.title)
+	if strings.TrimSpace(tr.body) != "" {
+		fmt.Fprintf(&b, "\n%s\n", strings.TrimSpace(tr.body))
+	}
+
+	if dryRun(ctx) || !commandExists("gh") {
+		return b.String()
+	}
+
+	if tr.isPR {
+		if diff := ghOutput(ctx, "pr", "diff", fmt.Sprint(tr.number), "--repo", tr.repo); diff != "" {
+			fmt.Fprintf(&b, "\n## Diff\n```diff\n%s\n```\n", strings.TrimSpace(diff))
+		}
+		if comments := ghOutput(ctx, "pr", "view", fmt.Sprint(tr.number), "--repo", tr.repo, "--json", "comments", "--jq", ".comments[] | \"@\\(.author.login): \\(.body)\""); comments != "" {
+			fmt.Fprintf(&b, "\n## Comments\n%s\n", strings.TrimSpace(comments))
+		}
+	} else {
+		if comments := ghOutput(ctx, "issue", "view", fmt.Sprint(tr.number), "--repo", tr.repo, "--json", "comments", "--jq", ".comments[] | \"@\\(.author.login): \\(.body)\""); comments != "" {
+			fmt.Fprintf(&b, "\n## Comments\n%s\n", strings.TrimSpace(comments))
+		}
+	}
+	return b.String()
+}
+
+// buildPrompt constructs the instruction sent to the agent.
+func buildPrompt(tr *trigger, context string) string {
+	target := "issue"
+	if tr.isPR {
+		target = "pull request"
+	}
+	request := tr.request
+	if request == "" {
+		request = "(no explicit instruction — review the " + target + " and respond helpfully)"
+	}
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "You are Kit, operating as an automated collaborator on the GitHub repository %s.\n\n", tr.repo)
+	fmt.Fprintf(&b, "@%s (access: %s) triggered you on %s #%d with this request:\n\n", tr.author, tr.association, target, tr.number)
+	fmt.Fprintf(&b, "%s\n\n", request)
+	fmt.Fprintf(&b, "## Context\n%s\n\n", strings.TrimSpace(context))
+	b.WriteString("Carry out the request. If you modify files, they will be committed to a new ")
+	b.WriteString("branch and a pull request will be opened automatically, so you do not need to ")
+	b.WriteString("commit or push yourself. Finish with a concise summary of what you did.")
+	return b.String()
+}
+
+// handleAgentEnd posts the agent's response, opens a PR for any uncommitted
+// changes, and swaps the reaction to signal completion.
+func handleAgentEnd(e ext.AgentEndEvent, ctx ext.Context) {
+	tr := activeTrigger
+	response := strings.TrimSpace(e.Response)
+	if response == "" {
+		response = "Kit finished without a textual response."
+	}
+
+	if e.StopReason == "error" {
+		comment := "⚠️ Kit hit an error while processing this request:\n\n" + response
+		postComment(ctx, tr, comment)
+		addReaction(ctx, tr, "confused")
+		ctx.Exit()
+		return
+	}
+
+	prURL := ""
+	if hasUncommittedChanges(ctx) {
+		prURL = openPullRequest(ctx, tr, response)
+	}
+
+	comment := response
+	if prURL != "" {
+		comment += "\n\n---\nOpened a pull request with the changes: " + prURL
+	}
+	postComment(ctx, tr, comment)
+	addReaction(ctx, tr, "rocket")
+	ctx.Exit()
+}
+
+// hasUncommittedChanges reports whether the working tree has changes the agent
+// produced. In dry-run it reports the value of KIT_GITHUB_FAKE_DIRTY so tests
+// stay deterministic.
+func hasUncommittedChanges(ctx ext.Context) bool {
+	if dryRun(ctx) {
+		return os.Getenv("KIT_GITHUB_FAKE_DIRTY") != ""
+	}
+	out := gitOutput(ctx, "status", "--porcelain")
+	return strings.TrimSpace(out) != ""
+}
+
+// openPullRequest commits the working tree as kit-agent[bot], pushes a branch,
+// and opens a PR. It returns the PR URL, or "" on failure / dry-run.
+func openPullRequest(ctx ext.Context, tr *trigger, summary string) string {
+	branch := fmt.Sprintf("kit/issue-%d-%d", tr.number, time.Now().Unix())
+
+	runGit(ctx, "checkout", "-b", branch)
+	runGit(ctx, "add", "-A")
+	runGit(ctx, "-c", "user.name="+botName, "-c", "user.email="+botEmail,
+		"commit", "-m", fmt.Sprintf("kit: address #%d", tr.number))
+	runGit(ctx, "push", "origin", "HEAD:"+branch)
+
+	title := fmt.Sprintf("kit: changes for #%d", tr.number)
+	body := fmt.Sprintf("Automated changes from Kit in response to #%d.\n\n%s", tr.number, summary)
+	if dryRun(ctx) {
+		ctx.Print(fmt.Sprintf("[dry-run] gh pr create --head %s --base %s", branch, tr.defaultBranch))
+		return ""
+	}
+	url := ghOutput(ctx, "pr", "create", "--repo", tr.repo,
+		"--head", branch, "--base", tr.defaultBranch,
+		"--title", title, "--body", body)
+	return strings.TrimSpace(url)
+}
+
+// addReaction adds an emoji reaction to the trigger comment.
+func addReaction(ctx ext.Context, tr *trigger, content string) {
+	path := fmt.Sprintf("/repos/%s/%s/comments/%d/reactions", tr.repo, tr.commentKind, tr.commentID)
+	if dryRun(ctx) || !commandExists("gh") {
+		ctx.Print(fmt.Sprintf("[dry-run] react %q on %s", content, path))
+		return
+	}
+	runCmd(ctx, "gh", "api", "-X", "POST", path, "-f", "content="+content)
+}
+
+// postComment posts a comment back on the triggering issue or pull request.
+func postComment(ctx ext.Context, tr *trigger, body string) {
+	sub := "issue"
+	if tr.isPR {
+		sub = "pr"
+	}
+	if dryRun(ctx) || !commandExists("gh") {
+		ctx.Print(fmt.Sprintf("[dry-run] gh %s comment %d --body <%d chars>", sub, tr.number, len(body)))
+		return
+	}
+	runCmd(ctx, "gh", sub, "comment", fmt.Sprint(tr.number), "--repo", tr.repo, "--body", body)
+}
+
+// --- thin subprocess helpers -------------------------------------------------
+
+func commandExists(name string) bool {
+	_, err := exec.LookPath(name)
+	return err == nil
+}
+
+// runGit runs a mutating git command, logging instead of executing in dry-run.
+func runGit(ctx ext.Context, args ...string) {
+	if dryRun(ctx) {
+		ctx.Print("[dry-run] git " + strings.Join(args, " "))
+		return
+	}
+	runCmd(ctx, "git", args...)
+}
+
+// gitOutput runs a read-only git command and returns its stdout.
+func gitOutput(ctx ext.Context, args ...string) string {
+	cmdCtx, cancel := context.WithTimeout(context.Background(), subprocessTimeout)
+	defer cancel()
+	cmd := exec.CommandContext(cmdCtx, "git", args...)
+	out, err := cmd.Output()
+	if err != nil {
+		ctx.PrintError(fmt.Sprintf("kit-github: git %s failed: %v", strings.Join(args, " "), err))
+		return ""
+	}
+	return string(out)
+}
+
+// ghOutput runs a gh command and returns its stdout.
+func ghOutput(ctx ext.Context, args ...string) string {
+	cmdCtx, cancel := context.WithTimeout(context.Background(), subprocessTimeout)
+	defer cancel()
+	cmd := exec.CommandContext(cmdCtx, "gh", args...)
+	out, err := cmd.Output()
+	if err != nil {
+		ctx.PrintError(fmt.Sprintf("kit-github: gh %s failed: %v", strings.Join(args, " "), err))
+		return ""
+	}
+	return string(out)
+}
+
+// runCmd runs a command for its side effects, surfacing failures via PrintError.
+func runCmd(ctx ext.Context, name string, args ...string) {
+	cmdCtx, cancel := context.WithTimeout(context.Background(), subprocessTimeout)
+	defer cancel()
+	cmd := exec.CommandContext(cmdCtx, name, args...)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		ctx.PrintError(fmt.Sprintf("kit-github: %s failed: %v\n%s", name, err, strings.TrimSpace(string(out))))
+	}
+}

examples/extensions/github-handler/main_test.go

@@ -0,0 +1,209 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/mark3labs/kit/internal/extensions"
+	"github.com/mark3labs/kit/pkg/extensions/test"
+)
+
+// writeEvent writes a GitHub event payload to a temp file and points
+// GITHUB_EVENT_PATH at it. It also forces the extension into dry-run and
+// pretends we are running inside GitHub Actions.
+func writeEvent(t *testing.T, payload string) {
+	t.Helper()
+	path := filepath.Join(t.TempDir(), "event.json")
+	if err := os.WriteFile(path, []byte(payload), 0o644); err != nil {
+		t.Fatalf("write event: %v", err)
+	}
+	t.Setenv("GITHUB_ACTIONS", "true")
+	t.Setenv("KIT_GITHUB_DRY_RUN", "1")
+	t.Setenv("GITHUB_EVENT_PATH", path)
+}
+
+const issueCommentEvent = `{
+  "action": "created",
+  "comment": {
+    "id": 555,
+    "body": "/kit fix the broken parser",
+    "author_association": "OWNER",
+    "user": {"login": "alice"}
+  },
+  "issue": {"number": 42, "title": "Parser crashes on empty input", "body": "It panics."},
+  "repository": {"full_name": "acme/widgets", "default_branch": "main"}
+}`
+
+func TestGitHubHandler_RegistersHandlers(t *testing.T) {
+	harness := test.New(t)
+	ext := harness.LoadFile("main.go")
+	if ext == nil {
+		t.Fatal("extension should not be nil")
+	}
+	test.AssertHasHandlers(t, harness, extensions.SessionStart)
+	test.AssertHasHandlers(t, harness, extensions.AgentEnd)
+}
+
+func TestGitHubHandler_InertOutsideActions(t *testing.T) {
+	// No GITHUB_ACTIONS env → the handler must do nothing.
+	t.Setenv("GITHUB_ACTIONS", "")
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit: %v", err)
+	}
+	if msgs := harness.Context().Messages; len(msgs) != 0 {
+		t.Errorf("expected no messages outside Actions, got %v", msgs)
+	}
+}
+
+func TestGitHubHandler_AuthorizedIssueComment(t *testing.T) {
+	writeEvent(t, issueCommentEvent)
+
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit: %v", err)
+	}
+
+	msgs := harness.Context().Messages
+	if len(msgs) != 1 {
+		t.Fatalf("expected exactly one driven prompt, got %d: %v", len(msgs), msgs)
+	}
+	prompt := msgs[0]
+	for _, want := range []string{
+		"fix the broken parser",         // the request
+		"acme/widgets",                  // the repo
+		"issue #42",                     // the target
+		"@alice",                        // the author
+		"Parser crashes on empty input", // context: title
+		"It panics.",                    // context: body
+	} {
+		if !strings.Contains(prompt, want) {
+			t.Errorf("prompt missing %q\n---\n%s", want, prompt)
+		}
+	}
+}
+
+func TestGitHubHandler_UnauthorizedAssociation(t *testing.T) {
+	writeEvent(t, strings.Replace(issueCommentEvent, `"OWNER"`, `"NONE"`, 1))
+
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit: %v", err)
+	}
+
+	if msgs := harness.Context().Messages; len(msgs) != 0 {
+		t.Fatalf("unauthorized author must not drive the agent, got %v", msgs)
+	}
+	if errs := harness.Context().GetPrintErrors(); len(errs) == 0 ||
+		!strings.Contains(strings.Join(errs, "\n"), "lacks write access") {
+		t.Errorf("expected a write-access error, got %v", errs)
+	}
+}
+
+func TestGitHubHandler_CommentWithoutToken(t *testing.T) {
+	writeEvent(t, strings.Replace(issueCommentEvent,
+		`"/kit fix the broken parser"`, `"just a normal comment"`, 1))
+
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit: %v", err)
+	}
+	if msgs := harness.Context().Messages; len(msgs) != 0 {
+		t.Fatalf("non-/kit comment must not drive the agent, got %v", msgs)
+	}
+}
+
+func TestGitHubHandler_MidSentenceMentionIgnored(t *testing.T) {
+	// An incidental mid-sentence mention of the token must not trigger Kit.
+	writeEvent(t, strings.Replace(issueCommentEvent,
+		`"/kit fix the broken parser"`, `"please review /kit behavior in the docs"`, 1))
+
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit: %v", err)
+	}
+	if msgs := harness.Context().Messages; len(msgs) != 0 {
+		t.Fatalf("mid-sentence /kit mention must not drive the agent, got %v", msgs)
+	}
+}
+
+func TestGitHubHandler_PullRequestReviewComment(t *testing.T) {
+	writeEvent(t, `{
+  "action": "created",
+  "comment": {
+    "id": 999,
+    "body": "/kit review this change",
+    "author_association": "COLLABORATOR",
+    "user": {"login": "bob"}
+  },
+  "pull_request": {"number": 7, "title": "Add caching", "body": "Speeds things up."},
+  "repository": {"full_name": "acme/widgets", "default_branch": "main"}
+}`)
+
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit: %v", err)
+	}
+	msgs := harness.Context().Messages
+	if len(msgs) != 1 {
+		t.Fatalf("expected one driven prompt, got %v", msgs)
+	}
+	if !strings.Contains(msgs[0], "pull request #7") {
+		t.Errorf("expected PR target in prompt:\n%s", msgs[0])
+	}
+}
+
+func TestGitHubHandler_AgentEndPostsComment(t *testing.T) {
+	writeEvent(t, issueCommentEvent)
+
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit session start: %v", err)
+	}
+	if _, err := harness.Emit(extensions.AgentEndEvent{
+		Response:   "Fixed the parser by guarding empty input.",
+		StopReason: "completed",
+	}); err != nil {
+		t.Fatalf("emit agent end: %v", err)
+	}
+
+	prints := strings.Join(harness.Context().GetPrints(), "\n")
+	if !strings.Contains(prints, "gh issue comment 42") {
+		t.Errorf("expected a dry-run comment post, got prints:\n%s", prints)
+	}
+}
+
+func TestGitHubHandler_AgentEndOpensPRWhenDirty(t *testing.T) {
+	writeEvent(t, issueCommentEvent)
+	t.Setenv("KIT_GITHUB_FAKE_DIRTY", "1")
+
+	harness := test.New(t)
+	harness.LoadFile("main.go")
+	if _, err := harness.Emit(extensions.SessionStartEvent{SessionID: "s1"}); err != nil {
+		t.Fatalf("emit session start: %v", err)
+	}
+	if _, err := harness.Emit(extensions.AgentEndEvent{
+		Response:   "Made changes.",
+		StopReason: "completed",
+	}); err != nil {
+		t.Fatalf("emit agent end: %v", err)
+	}
+
+	prints := strings.Join(harness.Context().GetPrints(), "\n")
+	if !strings.Contains(prints, "gh pr create") {
+		t.Errorf("expected a dry-run PR creation, got prints:\n%s", prints)
+	}
+	if !strings.Contains(prints, "git checkout -b kit/issue-42-") {
+		t.Errorf("expected a dry-run branch checkout, got prints:\n%s", prints)
+	}
+}

internal/acpserver/session.go

@@ -73,111 +73,70 @@ func (r *sessionRegistry) create(ctx context.Context, cwd string) (*acpSession,
 
 	// Wire extension context with headless implementations so extensions
 	// work in ACP mode. TUI-dependent features (widgets, prompts, editor)
-	// become no-ops or return cancelled; all data/model/tool APIs work
-	// identically to interactive mode.
+	// become no-ops or return cancelled; all data/model/tool APIs come from
+	// extbridge.BaseContext and work identically to interactive mode.
 	if kitInstance.Extensions().HasExtensions() {
-		kitInstance.Extensions().SetContext(extensions.Context{
-			SessionID:   sessionID,
-			CWD:         cwd,
-			Model:       kitInstance.GetModelString(),
-			Interactive: false,
+		// Use a background context for subagent spawns: the create() ctx is
+		// request-scoped and may be cancelled before extensions spawn anything.
+		ec := extbridge.BaseContext(context.Background(), kitInstance)
 
-			// Output — route through structured logger.
-			Print:      func(text string) { log.Debug("extension: print", "text", text) },
-			PrintInfo:  func(text string) { log.Info("extension: info", "text", text) },
-			PrintError: func(text string) { log.Error("extension: error", "text", text) },
-			PrintBlock: func(opts extensions.PrintBlockOpts) {
-				log.Info("extension: block", "subtitle", opts.Subtitle, "text", opts.Text)
-			},
+		ec.SessionID = sessionID
+		ec.CWD = cwd
+		ec.Model = kitInstance.GetModelString()
+		ec.Interactive = false
 
-			// Message injection — no-ops for now; ACP clients drive prompts.
-			SendMessage:   func(string) {},
-			CancelAndSend: func(string) {},
-			Exit:          func() {},
+		// Output — route through structured logger.
+		ec.Print = func(text string) { log.Debug("extension: print", "text", text) }
+		ec.PrintInfo = func(text string) { log.Info("extension: info", "text", text) }
+		ec.PrintError = func(text string) { log.Error("extension: error", "text", text) }
+		ec.PrintBlock = func(opts extensions.PrintBlockOpts) {
+			log.Info("extension: block", "subtitle", opts.Subtitle, "text", opts.Text)
+		}
 
-			// TUI widgets/chrome — silent no-ops (no TUI in ACP).
-			SetWidget:       func(extensions.WidgetConfig) {},
-			RemoveWidget:    func(string) {},
-			SetHeader:       func(extensions.HeaderFooterConfig) {},
-			RemoveHeader:    func() {},
-			SetFooter:       func(extensions.HeaderFooterConfig) {},
-			RemoveFooter:    func() {},
-			SetEditor:       func(extensions.EditorConfig) {},
-			ResetEditor:     func() {},
-			SetEditorText:   func(string) {},
-			SetUIVisibility: func(extensions.UIVisibility) {},
-			SetStatus:       func(string, string, int) {},
-			RemoveStatus:    func(string) {},
+		// Message injection — no-ops for now; ACP clients drive prompts.
+		ec.SendMessage = func(string) {}
+		ec.CancelAndSend = func(string) {}
+		ec.Exit = func() {}
 
-			// Interactive prompts — return cancelled (no user to prompt).
-			PromptSelect: func(extensions.PromptSelectConfig) extensions.PromptSelectResult {
-				return extensions.PromptSelectResult{Cancelled: true}
-			},
-			PromptConfirm: func(extensions.PromptConfirmConfig) extensions.PromptConfirmResult {
-				return extensions.PromptConfirmResult{Cancelled: true}
-			},
-			PromptInput: func(extensions.PromptInputConfig) extensions.PromptInputResult {
-				return extensions.PromptInputResult{Cancelled: true}
-			},
-			ShowOverlay: func(extensions.OverlayConfig) extensions.OverlayResult {
-				return extensions.OverlayResult{Cancelled: true, Index: -1}
-			},
-			SuspendTUI: func(callback func()) error { callback(); return nil },
+		// TUI widgets/chrome — silent no-ops (no TUI in ACP).
+		ec.SetWidget = func(extensions.WidgetConfig) {}
+		ec.RemoveWidget = func(string) {}
+		ec.SetHeader = func(extensions.HeaderFooterConfig) {}
+		ec.RemoveHeader = func() {}
+		ec.SetFooter = func(extensions.HeaderFooterConfig) {}
+		ec.RemoveFooter = func() {}
+		ec.SetEditor = func(extensions.EditorConfig) {}
+		ec.ResetEditor = func() {}
+		ec.SetEditorText = func(string) {}
+		ec.SetUIVisibility = func(extensions.UIVisibility) {}
+		ec.SetStatus = func(string, string, int) {}
+		ec.RemoveStatus = func(string) {}
 
-			// Data access — delegate to Kit instance.
-			GetContextStats: func() extensions.ContextStats {
-				s := kitInstance.GetContextStats()
-				return extensions.ContextStats{
-					EstimatedTokens: s.EstimatedTokens,
-					ContextLimit:    s.ContextLimit,
-					UsagePercent:    s.UsagePercent,
-					MessageCount:    s.MessageCount,
-				}
-			},
-			GetMessages:    func() []extensions.SessionMessage { return kitInstance.Extensions().GetSessionMessages() },
-			GetSessionPath: func() string { return kitInstance.GetSessionPath() },
-			AppendEntry: func(entryType, data string) (string, error) {
-				return kitInstance.Extensions().AppendEntry(entryType, data)
-			},
-			GetEntries: func(entryType string) []extensions.ExtensionEntry {
-				return kitInstance.Extensions().GetEntries(entryType)
-			},
+		// Interactive prompts — return cancelled (no user to prompt).
+		ec.PromptSelect = func(extensions.PromptSelectConfig) extensions.PromptSelectResult {
+			return extensions.PromptSelectResult{Cancelled: true}
+		}
+		ec.PromptConfirm = func(extensions.PromptConfirmConfig) extensions.PromptConfirmResult {
+			return extensions.PromptConfirmResult{Cancelled: true}
+		}
+		ec.PromptInput = func(extensions.PromptInputConfig) extensions.PromptInputResult {
+			return extensions.PromptInputResult{Cancelled: true}
+		}
+		ec.ShowOverlay = func(extensions.OverlayConfig) extensions.OverlayResult {
+			return extensions.OverlayResult{Cancelled: true, Index: -1}
+		}
+		ec.SuspendTUI = func(callback func()) error { callback(); return nil }
 
-			// Options, model, and tool management.
-			GetOption: func(name string) string { return kitInstance.Extensions().GetOption(name) },
-			SetOption: func(name, value string) { kitInstance.Extensions().SetOption(name, value) },
-			SetModel: func(modelString string) error {
-				previousModel := kitInstance.Extensions().GetContext().Model
-				if err := kitInstance.SetModel(context.Background(), modelString); err != nil {
-					return err
-				}
-				kitInstance.Extensions().UpdateContextModel(modelString)
-				kitInstance.Extensions().EmitModelChange(modelString, previousModel, "extension")
-				return nil
-			},
-			GetAvailableModels: func() []extensions.ModelInfoEntry { return kitInstance.GetAvailableModels() },
-			EmitCustomEvent:    func(name, data string) { kitInstance.Extensions().EmitCustomEvent(name, data) },
-			GetAllTools:        func() []extensions.ToolInfo { return kitInstance.Extensions().GetToolInfos() },
-			SetActiveTools:     func(names []string) { kitInstance.Extensions().SetActiveTools(names) },
+		// Render — fall back to logging.
+		ec.RenderMessage = func(name, content string) {
+			renderer := kitInstance.Extensions().GetMessageRenderer(name)
+			if renderer != nil && renderer.Render != nil {
+				content = renderer.Render(content, 80)
+			}
+			log.Info("extension: message", "renderer", name, "content", content)
+		}
 
-			// LLM completions and subagents.
-			Complete: func(req extensions.CompleteRequest) (extensions.CompleteResponse, error) {
-				return kitInstance.ExecuteCompletion(context.Background(), req)
-			},
-			SpawnSubagent: func(config extensions.SubagentConfig) (*extensions.SubagentHandle, *extensions.SubagentResult, error) {
-				return extbridge.SpawnSubagent(context.Background(), kitInstance, config)
-			},
-
-			// Render — fall back to logging.
-			RenderMessage: func(name, content string) {
-				renderer := kitInstance.Extensions().GetMessageRenderer(name)
-				if renderer != nil && renderer.Render != nil {
-					content = renderer.Render(content, 80)
-				}
-				log.Info("extension: message", "renderer", name, "content", content)
-			},
-			ReloadExtensions: func() error { return kitInstance.Extensions().Reload() },
-		})
+		kitInstance.Extensions().SetContext(ec)
 		kitInstance.Extensions().EmitSessionStart()
 	}
 

internal/app/messages.go

@@ -13,11 +13,6 @@ type MessageStore struct {
 	messages []kit.LLMMessage
 }
 
-// NewMessageStore creates an empty MessageStore.
-func NewMessageStore() *MessageStore {
-	return &MessageStore{}
-}
-
 // NewMessageStoreWithMessages creates a MessageStore pre-populated with the
 // given messages. This is used when loading an existing session at startup.
 func NewMessageStoreWithMessages(msgs []kit.LLMMessage) *MessageStore {

internal/app/messages_test.go

@@ -29,7 +29,7 @@ func textOf(msg kit.LLMMessage) string {
 // --------------------------------------------------------------------------
 
 func TestNewMessageStore_empty(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	if s == nil {
 		t.Fatal("expected non-nil store")
 	}
@@ -72,7 +72,7 @@ func TestNewMessageStoreWithMessages_isolatesInput(t *testing.T) {
 // --------------------------------------------------------------------------
 
 func TestAdd_appendsMessage(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	s.Add(makeTextMsg("user", "first"))
 	s.Add(makeTextMsg("assistant", "second"))
 
@@ -82,7 +82,7 @@ func TestAdd_appendsMessage(t *testing.T) {
 }
 
 func TestAdd_preservesOrder(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	texts := []string{"a", "b", "c"}
 	for _, t2 := range texts {
 		s.Add(makeTextMsg("user", t2))
@@ -100,7 +100,7 @@ func TestAdd_preservesOrder(t *testing.T) {
 // --------------------------------------------------------------------------
 
 func TestReplace_swapsHistory(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	s.Add(makeTextMsg("user", "old"))
 
 	replacement := []kit.LLMMessage{
@@ -120,7 +120,7 @@ func TestReplace_swapsHistory(t *testing.T) {
 
 // Replace must deep-copy the incoming slice.
 func TestReplace_isolatesInput(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	replacement := []kit.LLMMessage{makeTextMsg("user", "original")}
 	s.Replace(replacement)
 
@@ -137,7 +137,7 @@ func TestReplace_isolatesInput(t *testing.T) {
 // --------------------------------------------------------------------------
 
 func TestGetAll_returnsCopy(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	s.Add(makeTextMsg("user", "hello"))
 
 	got := s.GetAll()
@@ -151,7 +151,7 @@ func TestGetAll_returnsCopy(t *testing.T) {
 }
 
 func TestGetAll_emptyStore(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	got := s.GetAll()
 	if len(got) != 0 {
 		t.Fatalf("expected empty slice, got %d elements", len(got))
@@ -163,7 +163,7 @@ func TestGetAll_emptyStore(t *testing.T) {
 // --------------------------------------------------------------------------
 
 func TestClear_removesAllMessages(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	s.Add(makeTextMsg("user", "a"))
 	s.Add(makeTextMsg("user", "b"))
 	s.Clear()
@@ -174,7 +174,7 @@ func TestClear_removesAllMessages(t *testing.T) {
 }
 
 func TestClear_allowsSubsequentAdds(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	s.Add(makeTextMsg("user", "before"))
 	s.Clear()
 	s.Add(makeTextMsg("user", "after"))
@@ -193,7 +193,7 @@ func TestClear_allowsSubsequentAdds(t *testing.T) {
 // --------------------------------------------------------------------------
 
 func TestConcurrentAccess(t *testing.T) {
-	s := NewMessageStore()
+	s := NewMessageStoreWithMessages(nil)
 	done := make(chan struct{})
 
 	// Writer goroutine.

internal/auth/credentials.go

@@ -513,6 +513,20 @@ func validateAnthropicAPIKey(apiKey string) error {
 	return nil
 }
 
+// CredentialSourceOAuth is the source description returned by
+// GetAnthropicAPIKey when the key resolves to stored OAuth credentials.
+// Consumers should compare against this constant (or use IsAnthropicOAuth)
+// rather than matching the string literal.
+const CredentialSourceOAuth = "stored OAuth credentials"
+
+// IsAnthropicOAuth reports whether the active Anthropic credential resolves
+// to a stored OAuth token (in which case the user is not billed per-token).
+// flagValue is the --provider-api-key flag value (may be empty).
+func IsAnthropicOAuth(flagValue string) bool {
+	_, source, err := GetAnthropicAPIKey(flagValue)
+	return err == nil && source == CredentialSourceOAuth
+}
+
 // GetAnthropicAPIKey retrieves an Anthropic API key from multiple sources in priority order:
 // 1. Command-line flag value (highest priority)
 // 2. Stored credentials (OAuth or API key)
@@ -535,7 +549,7 @@ func GetAnthropicAPIKey(flagValue string) (string, string, error) {
 				if err != nil {
 					return "", "", fmt.Errorf("failed to get valid OAuth token: %w", err)
 				}
-				return token, "stored OAuth credentials", nil
+				return token, CredentialSourceOAuth, nil
 			} else if creds.Type == "api_key" && creds.APIKey != "" {
 				return creds.APIKey, "stored API key", nil
 			}

internal/config/config.go

@@ -493,6 +493,12 @@ mcpServers:
 #     maxTokens: 16384
 #     systemPrompt: "You are a deep reasoning assistant."  # or a file path
 
+# Skills configuration (all optional)
+# no-skills: false                          # Set to true to disable all skill loading
+# skill:                                    # Explicit skill files/dirs (disables auto-discovery)
+#   - "/path/to/skill.md"
+# skills-dir: "/path/to/skills"            # Override project-local directory for auto-discovery
+
 # API Configuration (can also use environment variables)
 # provider-api-key: "your-api-key"         # API key for OpenAI, Anthropic, or Google
 # provider-url: "https://api.openai.com/v1" # Base URL for OpenAI, Anthropic, or Ollama

internal/config/config_test.go

@@ -205,6 +205,9 @@ func TestEnsureConfigExists(t *testing.T) {
 		"type: \"local\"",
 		"type: \"remote\"",
 		"Core tools",
+		"# Skills configuration",
+		"no-skills:",
+		"skills-dir:",
 	}
 
 	for _, expected := range expectedSections {

internal/config/substitution.go

@@ -56,9 +56,3 @@ func (e *EnvSubstituter) SubstituteEnvVars(content string) (string, error) {
 
 	return result, nil
 }
-
-// HasEnvVars checks if content contains environment variable patterns (${env://...}).
-// This is useful for determining if substitution is needed before processing.
-func HasEnvVars(content string) bool {
-	return envVarPattern.MatchString(content)
-}

internal/config/substitution_test.go

@@ -187,41 +187,3 @@ func TestEnvSubstituter_SubstituteEnvVars(t *testing.T) {
 		})
 	}
 }
-
-func TestHasEnvVars(t *testing.T) {
-	tests := []struct {
-		name     string
-		content  string
-		expected bool
-	}{
-		{
-			name:     "has env vars",
-			content:  `{"token": "${env://GITHUB_TOKEN}"}`,
-			expected: true,
-		},
-		{
-			name:     "has env vars with default",
-			content:  `{"debug": "${env://DEBUG:-false}"}`,
-			expected: true,
-		},
-		{
-			name:     "no env vars",
-			content:  `{"name": "${username}", "normal": "value"}`,
-			expected: false,
-		},
-		{
-			name:     "empty content",
-			content:  "",
-			expected: false,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := HasEnvVars(tt.content)
-			if result != tt.expected {
-				t.Errorf("Expected %v, got %v", tt.expected, result)
-			}
-		})
-	}
-}

internal/core/bash.go

@@ -59,12 +59,6 @@ func passwordPromptFromContext(ctx context.Context) PasswordPromptCallback {
 	return nil
 }
 
-// ContextWithSudoPassword returns a new context with the sudo password set.
-// When present, the bash tool will use sudo -S to pipe this password to sudo commands.
-func ContextWithSudoPassword(ctx context.Context, password string) context.Context {
-	return context.WithValue(ctx, sudoPasswordKey, password)
-}
-
 // sudoPasswordFromContext retrieves the sudo password from context.
 func sudoPasswordFromContext(ctx context.Context) string {
 	if pw, ok := ctx.Value(sudoPasswordKey).(string); ok {

internal/core/bash_test.go

@@ -183,7 +183,7 @@ func TestRewriteSudoForStdin(t *testing.T) {
 
 func TestSudoPasswordFromContext(t *testing.T) {
 	// Test with password in context
-	ctx := ContextWithSudoPassword(context.Background(), "secret123")
+	ctx := context.WithValue(context.Background(), sudoPasswordKey, "secret123")
 	pw := sudoPasswordFromContext(ctx)
 	if pw != "secret123" {
 		t.Errorf("expected password 'secret123', got %q", pw)

internal/extbridge/context.go

@@ -0,0 +1,234 @@
+package extbridge
+
+import (
+	"context"
+
+	"github.com/mark3labs/kit/internal/extensions"
+	kit "github.com/mark3labs/kit/pkg/kit"
+)
+
+// BaseContext returns an extensions.Context populated with the headless,
+// TUI-independent delegation fields: data access, state, options,
+// model/tool management, completions, subagents, tree navigation, skills,
+// template parsing, and model resolution.
+//
+// Callers overlay their UI-specific fields (print routes, widgets, prompts,
+// editor, TUI-aware SetModel/ReloadExtensions, etc.) on the returned value:
+// cmd/extension_context.go for the interactive TUI and
+// internal/acpserver/session.go for headless ACP mode. Keeping the shared
+// half here means a new data-access Context field only has to be wired once.
+//
+// ctx is used for subagent spawns; pass a long-lived context (not a
+// per-request one) so later spawns aren't cancelled prematurely.
+func BaseContext(ctx context.Context, kitInstance *kit.Kit) extensions.Context {
+	return extensions.Context{
+		// -------------------------------------------------------------------
+		// Data access
+		// -------------------------------------------------------------------
+		GetContextStats: func() extensions.ContextStats {
+			s := kitInstance.GetContextStats()
+			return extensions.ContextStats{
+				EstimatedTokens: s.EstimatedTokens,
+				ContextLimit:    s.ContextLimit,
+				UsagePercent:    s.UsagePercent,
+				MessageCount:    s.MessageCount,
+			}
+		},
+		GetMessages: func() []extensions.SessionMessage {
+			return kitInstance.Extensions().GetSessionMessages()
+		},
+		GetSessionPath: func() string {
+			return kitInstance.GetSessionPath()
+		},
+		AppendEntry: func(entryType string, data string) (string, error) {
+			return kitInstance.Extensions().AppendEntry(entryType, data)
+		},
+		GetEntries: func(entryType string) []extensions.ExtensionEntry {
+			return kitInstance.Extensions().GetEntries(entryType)
+		},
+
+		// -------------------------------------------------------------------
+		// Extension state
+		// -------------------------------------------------------------------
+		SetState: func(key string, value string) {
+			kitInstance.Extensions().SetState(key, value)
+		},
+		GetState: func(key string) (string, bool) {
+			return kitInstance.Extensions().GetState(key)
+		},
+		DeleteState: func(key string) {
+			kitInstance.Extensions().DeleteState(key)
+		},
+		ListState: func() []string {
+			return kitInstance.Extensions().ListState()
+		},
+
+		// -------------------------------------------------------------------
+		// Options, model, and tool management
+		// -------------------------------------------------------------------
+		GetOption: func(name string) string {
+			return kitInstance.Extensions().GetOption(name)
+		},
+		SetOption: func(name string, value string) {
+			kitInstance.Extensions().SetOption(name, value)
+		},
+		// Headless model switch. The interactive TUI overrides this with a
+		// version that also notifies the TUI and refreshes the usage tracker.
+		SetModel: func(modelString string) error {
+			previousModel := kitInstance.Extensions().GetContext().Model
+			if err := kitInstance.SetModel(context.Background(), modelString); err != nil {
+				return err
+			}
+			kitInstance.Extensions().UpdateContextModel(modelString)
+			kitInstance.Extensions().EmitModelChange(modelString, previousModel, "extension")
+			return nil
+		},
+		GetAvailableModels: func() []extensions.ModelInfoEntry {
+			return kitInstance.GetAvailableModels()
+		},
+		EmitCustomEvent: func(name string, data string) {
+			kitInstance.Extensions().EmitCustomEvent(name, data)
+		},
+		GetAllTools: func() []extensions.ToolInfo {
+			return kitInstance.Extensions().GetToolInfos()
+		},
+		SetActiveTools: func(names []string) {
+			kitInstance.Extensions().SetActiveTools(names)
+		},
+		// Headless reload. The interactive TUI overrides this to also
+		// refresh widgets/status/commands.
+		ReloadExtensions: func() error {
+			return kitInstance.Extensions().Reload()
+		},
+
+		// -------------------------------------------------------------------
+		// LLM completions and subagents
+		// -------------------------------------------------------------------
+		Complete: func(req extensions.CompleteRequest) (extensions.CompleteResponse, error) {
+			return kitInstance.ExecuteCompletion(context.Background(), req)
+		},
+		SpawnSubagent: func(config extensions.SubagentConfig) (*extensions.SubagentHandle, *extensions.SubagentResult, error) {
+			return SpawnSubagent(ctx, kitInstance, config)
+		},
+
+		// -------------------------------------------------------------------
+		// Tree Navigation API
+		// -------------------------------------------------------------------
+		GetTreeNode: func(entryID string) *extensions.TreeNode {
+			node := kitInstance.GetTreeNode(entryID)
+			if node == nil {
+				return nil
+			}
+			return &extensions.TreeNode{
+				ID:        node.ID,
+				ParentID:  node.ParentID,
+				Type:      node.Type,
+				Role:      node.Role,
+				Content:   node.Content,
+				Model:     node.Model,
+				Provider:  node.Provider,
+				Timestamp: node.Timestamp,
+				Children:  node.Children,
+			}
+		},
+		GetCurrentBranch: func() []extensions.TreeNode {
+			nodes := kitInstance.GetCurrentBranch()
+			result := make([]extensions.TreeNode, len(nodes))
+			for i, n := range nodes {
+				result[i] = extensions.TreeNode{
+					ID:        n.ID,
+					ParentID:  n.ParentID,
+					Type:      n.Type,
+					Role:      n.Role,
+					Content:   n.Content,
+					Model:     n.Model,
+					Provider:  n.Provider,
+					Timestamp: n.Timestamp,
+					Children:  n.Children,
+				}
+			}
+			return result
+		},
+		GetChildren: func(parentID string) []string {
+			return kitInstance.GetChildren(parentID)
+		},
+		NavigateTo: func(entryID string) extensions.TreeNavigationResult {
+			err := kitInstance.NavigateTo(entryID)
+			if err != nil {
+				return extensions.TreeNavigationResult{Success: false, Error: err.Error()}
+			}
+			return extensions.TreeNavigationResult{Success: true}
+		},
+		SummarizeBranch: func(fromID, toID string) string {
+			summary, _ := kitInstance.SummarizeBranch(fromID, toID)
+			return summary
+		},
+		CollapseBranch: func(fromID, toID, summary string) extensions.TreeNavigationResult {
+			err := kitInstance.CollapseBranch(fromID, toID, summary)
+			if err != nil {
+				return extensions.TreeNavigationResult{Success: false, Error: err.Error()}
+			}
+			return extensions.TreeNavigationResult{Success: true}
+		},
+
+		// -------------------------------------------------------------------
+		// Skill Loading API (context-injection variants are TUI-specific and
+		// wired by the interactive overlay)
+		// -------------------------------------------------------------------
+		LoadSkill: func(path string) (*extensions.Skill, string) {
+			s, err := kitInstance.LoadSkillForExtension(path)
+			return s, err
+		},
+		LoadSkillsFromDir: func(dir string) extensions.SkillLoadResult {
+			return kitInstance.LoadSkillsFromDirForExtension(dir)
+		},
+		DiscoverSkills: func() extensions.SkillLoadResult {
+			skills := kitInstance.DiscoverSkillsForExtension()
+			return extensions.SkillLoadResult{Skills: skills}
+		},
+		GetAvailableSkills: func() []extensions.Skill {
+			return kitInstance.DiscoverSkillsForExtension()
+		},
+
+		// -------------------------------------------------------------------
+		// Template Parsing API
+		// -------------------------------------------------------------------
+		ParseTemplate: func(name, content string) extensions.PromptTemplate {
+			return kit.ParseTemplate(name, content)
+		},
+		RenderTemplate: func(tpl extensions.PromptTemplate, vars map[string]string) string {
+			return kit.RenderTemplate(tpl, vars)
+		},
+		ParseArguments: func(input string, pattern extensions.ArgumentPattern) extensions.ParseResult {
+			return kit.ParseArguments(input, pattern)
+		},
+		SimpleParseArguments: func(input string, count int) []string {
+			return kit.SimpleParseArguments(input, count)
+		},
+		EvaluateModelConditional: func(condition string) bool {
+			return kit.EvaluateModelConditional(kitInstance.Extensions().GetContext().Model, condition)
+		},
+		RenderWithModelConditionals: func(content string) string {
+			return kit.RenderWithModelConditionals(content, kitInstance.Extensions().GetContext().Model)
+		},
+
+		// -------------------------------------------------------------------
+		// Model Resolution API
+		// -------------------------------------------------------------------
+		ResolveModelChain: func(preferences []string) extensions.ModelResolutionResult {
+			return kit.ResolveModelChain(preferences)
+		},
+		GetModelCapabilities: func(model string) (extensions.ModelCapabilities, string) {
+			return kit.GetModelCapabilities(model)
+		},
+		CheckModelAvailable: func(model string) bool {
+			return kit.CheckModelAvailable(model)
+		},
+		GetCurrentProvider: func() string {
+			return kit.GetCurrentProvider(kitInstance.Extensions().GetContext().Model)
+		},
+		GetCurrentModelID: func() string {
+			return kit.GetCurrentModelID(kitInstance.Extensions().GetContext().Model)
+		},
+	}
+}

internal/extensions/loader.go

@@ -372,8 +372,12 @@ func loadSingleExtension(path string) (*LoadedExtension, error) {
 		Handlers: make(map[EventType][]HandlerFunc),
 	}
 
-	// Create a fresh interpreter.
-	i := interp.New(interp.Options{})
+	// Create a fresh interpreter. Yaegi runs extensions in restricted mode,
+	// where os.Getenv/os.LookupEnv/os.Environ read from a virtualized
+	// environment rather than the real one. Seed it with the process
+	// environment so extensions can read variables (e.g. CI-provided ones
+	// like GITHUB_EVENT_PATH) without being able to mutate the host's env.
+	i := interp.New(interp.Options{Env: os.Environ()})
 
 	// Expose the Go stdlib. The base set covers most packages; the
 	// unrestricted set adds os/exec so extensions can spawn processes.

internal/extensions/toolkinds.go

@@ -0,0 +1,38 @@
+package extensions
+
+// ToolKind constants classify what a tool does, enabling UIs to render
+// appropriate visualizations (e.g. diff view for edit tools, command+output
+// for execute tools) and file trackers to identify which results contain
+// modifications.
+//
+// This is the single source of truth for tool-kind classification; the
+// pkg/kit SDK re-exports these constants.
+const (
+	ToolKindExecute  = "execute" // Shell execution (bash)
+	ToolKindEdit     = "edit"    // File modification (edit, write)
+	ToolKindRead     = "read"    // File reading (read, ls)
+	ToolKindSearch   = "search"  // Content/file search (grep, find)
+	ToolKindSubagent = "agent"   // Subagent spawning (subagent)
+)
+
+// coreToolKinds maps built-in tool names to their kind classification.
+// MCP and extension tools without an entry default to ToolKindExecute.
+var coreToolKinds = map[string]string{
+	"bash":     ToolKindExecute,
+	"edit":     ToolKindEdit,
+	"write":    ToolKindEdit,
+	"read":     ToolKindRead,
+	"ls":       ToolKindRead,
+	"grep":     ToolKindSearch,
+	"find":     ToolKindSearch,
+	"subagent": ToolKindSubagent,
+}
+
+// ToolKindFor returns the ToolKind for a given tool name, defaulting to
+// ToolKindExecute for unknown tools (including MCP tools).
+func ToolKindFor(toolName string) string {
+	if kind, ok := coreToolKinds[toolName]; ok {
+		return kind
+	}
+	return ToolKindExecute
+}

internal/extensions/wrapper.go

@@ -40,27 +40,6 @@ func ExtensionToolsAsLLMTools(defs []ToolDef, runner *Runner) []fantasy.AgentToo
 	return tools
 }
 
-// coreToolKinds maps built-in tool names to their kind classification.
-var coreToolKinds = map[string]string{
-	"bash":     "execute",
-	"edit":     "edit",
-	"write":    "edit",
-	"read":     "read",
-	"ls":       "read",
-	"grep":     "search",
-	"find":     "search",
-	"subagent": "agent",
-}
-
-// toolKindFor returns the ToolKind for a given tool name, defaulting to
-// "execute" for unknown tools (including MCP tools).
-func toolKindFor(toolName string) string {
-	if kind, ok := coreToolKinds[toolName]; ok {
-		return kind
-	}
-	return "execute"
-}
-
 // parseToolArgsJSON attempts to parse JSON-encoded tool args into a map.
 // Returns nil on failure (non-fatal convenience parsing).
 func parseToolArgsJSON(input string) map[string]any {
@@ -93,7 +72,7 @@ func (w *wrappedTool) Run(ctx context.Context, call fantasy.ToolCall) (fantasy.T
 			fmt.Sprintf("Error: tool %q is currently disabled", toolName)), nil
 	}
 
-	kind := toolKindFor(toolName)
+	kind := ToolKindFor(toolName)
 
 	// 1. Emit ToolCall — extensions can block execution.
 	if w.runner.HasHandlers(ToolCall) {

internal/models/custom.go

@@ -69,13 +69,6 @@ func modelConfigToModelInfo(modelID string, cfg CustomModelConfig) ModelInfo {
 	return info
 }
 
-// LoadModelSettingsFromConfig loads per-model generation parameter overrides
-// from the process-global viper store. Keys are "provider/model" strings.
-// Returns nil if no model settings are configured.
-func LoadModelSettingsFromConfig() map[string]*GenerationParams {
-	return LoadModelSettingsFrom(viper.GetViper())
-}
-
 // LoadModelSettingsFrom loads per-model generation parameter overrides from the
 // supplied per-instance store. When v is nil the process-global store is used.
 // Keys are "provider/model" strings. Returns nil if no model settings are

internal/models/providers.go

@@ -932,7 +932,7 @@ func createAnthropicProvider(ctx context.Context, config *ProviderConfig, modelN
 	}
 
 	// Handle OAuth vs API key authentication
-	if strings.HasPrefix(source, "stored OAuth") {
+	if source == auth.CredentialSourceOAuth {
 		httpClient := createOAuthHTTPClient(apiKey, config.TLSSkipVerify)
 		opts = append(opts, anthropic.WithHTTPClient(httpClient))
 		// Note: For OAuth, the API key is set as a placeholder; the transport handles auth

internal/prompts/template.go

@@ -70,7 +70,8 @@ func ParseTemplate(path string) (*PromptTemplate, error) {
 }
 
 // ParseCommandArgs splits a command line into arguments respecting quotes.
-// It handles single quotes, double quotes, and backslash escaping.
+// It handles single quotes, double quotes, backslash escaping, and splits on
+// spaces and tabs.
 func ParseCommandArgs(input string) []string {
 	var args []string
 	var current strings.Builder
@@ -78,7 +79,7 @@ func ParseCommandArgs(input string) []string {
 	inDoubleQuote := false
 	escaped := false
 
-	for i, r := range input {
+	for _, r := range input {
 		if escaped {
 			current.WriteRune(r)
 			escaped = false
@@ -101,7 +102,7 @@ func ParseCommandArgs(input string) []string {
 			continue
 		}
 
-		if r == ' ' && !inSingleQuote && !inDoubleQuote {
+		if (r == ' ' || r == '\t') && !inSingleQuote && !inDoubleQuote {
 			if current.Len() > 0 {
 				args = append(args, current.String())
 				current.Reset()
@@ -110,7 +111,6 @@ func ParseCommandArgs(input string) []string {
 		}
 
 		current.WriteRune(r)
-		_ = i // silence unused warning when we need position later
 	}
 
 	if current.Len() > 0 {
@@ -325,8 +325,3 @@ func (t *PromptTemplate) Expand(argsInput string) string {
 	args := ParseCommandArgs(argsInput)
 	return SubstituteArgs(t.Content, args)
 }
-
-// ExpandWithArgs substitutes the provided arguments into the template content.
-func (t *PromptTemplate) ExpandWithArgs(args []string) string {
-	return SubstituteArgs(t.Content, args)
-}

internal/skills/templates.go

@@ -18,8 +18,11 @@ type PromptTemplate struct {
 	Variables []string
 }
 
-// variableRe matches {{variable_name}} placeholders.
-var variableRe = regexp.MustCompile(`\{\{(\w+)\}\}`)
+// variableRe matches {{variable_name}} placeholders, tolerating surrounding
+// whitespace inside the braces (e.g. {{ name }}). This is the canonical
+// template grammar shared by skill prompts and the extension template API
+// (pkg/kit ParseTemplate/RenderTemplate delegate here).
+var variableRe = regexp.MustCompile(`\{\{\s*(\w+)\s*\}\}`)
 
 // NewPromptTemplate creates a PromptTemplate, automatically extracting
 // variable names from {{...}} placeholders in content.
@@ -50,11 +53,13 @@ func LoadPromptTemplate(path string) (*PromptTemplate, error) {
 // Expand replaces all {{variable}} placeholders with values from the
 // provided map.  Missing variables are left as-is (no error).
 func (t *PromptTemplate) Expand(values map[string]string) string {
-	result := t.Content
-	for k, v := range values {
-		result = strings.ReplaceAll(result, "{{"+k+"}}", v)
-	}
-	return result
+	return variableRe.ReplaceAllStringFunc(t.Content, func(m string) string {
+		name := variableRe.FindStringSubmatch(m)[1]
+		if v, ok := values[name]; ok {
+			return v
+		}
+		return m
+	})
 }
 
 // ExpandStrict replaces all {{variable}} placeholders and returns an error

internal/tools/mcp.go

@@ -641,30 +641,16 @@ func (m *MCPToolManager) ExecuteTool(ctx context.Context, prefixedName, inputJSO
 			Request: mcp.Request{Method: "tools/call"},
 			Params:  callParams,
 		}
-		result, callErr := conn.client.CallTool(ctx, callRequest)
-		if callErr != nil {
-			if m.connectionPool.oauthFlow != nil && IsOAuthError(callErr) {
-				if flowErr := m.connectionPool.oauthFlow.RunAuthFlow(ctx, mapping.serverName, callErr); flowErr != nil {
-					return nil, fmt.Errorf("OAuth re-authorization failed for tool %s: %w", mapping.originalName, flowErr)
-				}
-				result, callErr = conn.client.CallTool(ctx, callRequest)
-				if callErr != nil {
-					m.connectionPool.HandleConnectionError(mapping.serverName, callErr)
-					return nil, fmt.Errorf("failed to call mcp tool after re-auth: %w", callErr)
-				}
-			} else {
-				m.connectionPool.HandleConnectionError(mapping.serverName, callErr)
-				return nil, fmt.Errorf("failed to call mcp tool: %w", callErr)
-			}
+		var result *mcp.CallToolResult
+		err := m.withOAuthRetry(ctx, mapping.serverName, mapping.originalName, func() error {
+			var callErr error
+			result, callErr = conn.client.CallTool(ctx, callRequest)
+			return callErr
+		})
+		if err != nil {
+			return nil, err
 		}
-		marshaledResult, mErr := json.Marshal(result)
-		if mErr != nil {
-			return nil, fmt.Errorf("failed to marshal mcp tool result: %w", mErr)
-		}
-		return &MCPToolResult{
-			Content: string(marshaledResult),
-			IsError: result.IsError,
-		}, nil
+		return marshalToolResult(result)
 	}
 
 	// Task-augmented path. Bypass the upstream CallTool helper because its
@@ -683,40 +669,25 @@ func (m *MCPToolManager) ExecuteTool(ctx context.Context, prefixedName, inputJSO
 			m.connectionPool.HandleConnectionError(mapping.serverName, callErr)
 			return nil, fmt.Errorf("failed to call mcp tool: %w", callErr)
 		}
-		marshaledResult, mErr := json.Marshal(result)
-		if mErr != nil {
-			return nil, fmt.Errorf("failed to marshal mcp tool result: %w", mErr)
-		}
-		return &MCPToolResult{Content: string(marshaledResult), IsError: result.IsError}, nil
+		return marshalToolResult(result)
 	}
 
-	callResult, taskResult, callErr := callToolWithTask(ctx, rawClient, callParams)
-	if callErr != nil {
-		if m.connectionPool.oauthFlow != nil && IsOAuthError(callErr) {
-			if flowErr := m.connectionPool.oauthFlow.RunAuthFlow(ctx, mapping.serverName, callErr); flowErr != nil {
-				return nil, fmt.Errorf("OAuth re-authorization failed for tool %s: %w", mapping.originalName, flowErr)
-			}
-			callResult, taskResult, callErr = callToolWithTask(ctx, rawClient, callParams)
-			if callErr != nil {
-				m.connectionPool.HandleConnectionError(mapping.serverName, callErr)
-				return nil, fmt.Errorf("failed to call mcp tool after re-auth: %w", callErr)
-			}
-		} else {
-			m.connectionPool.HandleConnectionError(mapping.serverName, callErr)
-			return nil, fmt.Errorf("failed to call mcp tool: %w", callErr)
-		}
+	var (
+		callResult *mcp.CallToolResult
+		taskResult *mcp.CreateTaskResult
+	)
+	err = m.withOAuthRetry(ctx, mapping.serverName, mapping.originalName, func() error {
+		var callErr error
+		callResult, taskResult, callErr = callToolWithTask(ctx, rawClient, callParams)
+		return callErr
+	})
+	if err != nil {
+		return nil, err
 	}
 
 	// Server chose to answer synchronously — same shape as the no-task path.
 	if callResult != nil {
-		marshaledResult, mErr := json.Marshal(callResult)
-		if mErr != nil {
-			return nil, fmt.Errorf("failed to marshal mcp tool result: %w", mErr)
-		}
-		return &MCPToolResult{
-			Content: string(marshaledResult),
-			IsError: callResult.IsError,
-		}, nil
+		return marshalToolResult(callResult)
 	}
 
 	// Asynchronous task path: poll until terminal, then return the result.
@@ -732,18 +703,50 @@ func (m *MCPToolManager) ExecuteTool(ctx context.Context, prefixedName, inputJSO
 	}
 
 	// Adapt TaskResultResult → CallToolResult for downstream JSON shape parity.
-	adapted := &mcp.CallToolResult{
+	return marshalToolResult(&mcp.CallToolResult{
 		Content:           final.Content,
 		StructuredContent: final.StructuredContent,
 		IsError:           final.IsError,
+	})
+}
+
+// withOAuthRetry runs call once; when it fails with an OAuth error and an
+// OAuth flow is configured, it re-authorizes the server and retries once.
+// Connection failures are reported to the pool and wrapped uniformly. This
+// consolidates the retry/error chain shared by the synchronous and
+// task-augmented tool-call paths.
+func (m *MCPToolManager) withOAuthRetry(ctx context.Context, serverName, toolName string, call func() error) error {
+	callErr := call()
+	if callErr == nil {
+		return nil
 	}
-	marshaledResult, mErr := json.Marshal(adapted)
-	if mErr != nil {
-		return nil, fmt.Errorf("failed to marshal mcp tool result: %w", mErr)
+	if m.connectionPool.oauthFlow != nil && IsOAuthError(callErr) {
+		if flowErr := m.connectionPool.oauthFlow.RunAuthFlow(ctx, serverName, callErr); flowErr != nil {
+			return fmt.Errorf("OAuth re-authorization failed for tool %s: %w", toolName, flowErr)
+		}
+		if callErr = call(); callErr != nil {
+			m.connectionPool.HandleConnectionError(serverName, callErr)
+			return fmt.Errorf("failed to call mcp tool after re-auth: %w", callErr)
+		}
+		return nil
+	}
+	m.connectionPool.HandleConnectionError(serverName, callErr)
+	return fmt.Errorf("failed to call mcp tool: %w", callErr)
+}
+
+// marshalToolResult converts an MCP CallToolResult into the JSON-encoded
+// MCPToolResult shape returned to the agent.
+func marshalToolResult(result *mcp.CallToolResult) (*MCPToolResult, error) {
+	if result == nil {
+		return nil, errors.New("mcp tool call returned nil result")
+	}
+	marshaled, err := json.Marshal(result)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal mcp tool result: %w", err)
 	}
 	return &MCPToolResult{
-		Content: string(marshaledResult),
-		IsError: final.IsError,
+		Content: string(marshaled),
+		IsError: result.IsError,
 	}, nil
 }
 

internal/ui/factory.go

@@ -2,7 +2,6 @@ package ui
 
 import (
 	"fmt"
-	"strings"
 
 	"github.com/mark3labs/kit/internal/auth"
 	"github.com/mark3labs/kit/internal/models"
@@ -44,28 +43,39 @@ func parseModelName(modelString string) (provider, model string) {
 // ollama or unrecognised models). This is used by the interactive TUI path
 // which doesn't go through SetupCLI.
 func CreateUsageTracker(modelString, providerAPIKey string) *UsageTracker {
-	provider, model := parseModelName(modelString)
-	if provider == "unknown" || model == "unknown" || provider == "ollama" {
-		return nil
-	}
-
-	registry := models.GetGlobalRegistry()
-	modelInfo := registry.LookupModel(provider, model)
+	modelInfo, provider := lookupTrackableModel(modelString)
 	if modelInfo == nil {
 		return nil
 	}
-
-	isOAuth := false
-	if provider == "anthropic" {
-		_, source, err := auth.GetAnthropicAPIKey(providerAPIKey)
-		if err == nil && strings.HasPrefix(source, "stored OAuth") {
-			isOAuth = true
-		}
-	}
-
+	isOAuth := provider == "anthropic" && auth.IsAnthropicOAuth(providerAPIKey)
 	return NewUsageTracker(modelInfo, provider, 80, isOAuth)
 }
 
+// UpdateUsageTrackerForModel refreshes an existing tracker after a model
+// switch so token counting and cost reporting use the new model's metadata.
+// No-op for a nil tracker or untrackable models (unknown/ollama).
+func UpdateUsageTrackerForModel(t *UsageTracker, modelString, providerAPIKey string) {
+	if t == nil {
+		return
+	}
+	modelInfo, provider := lookupTrackableModel(modelString)
+	if modelInfo == nil {
+		return
+	}
+	isOAuth := provider == "anthropic" && auth.IsAnthropicOAuth(providerAPIKey)
+	t.UpdateModelInfo(modelInfo, provider, isOAuth)
+}
+
+// lookupTrackableModel resolves a model string to registry metadata, returning
+// nil for models without usage tracking support (unknown or ollama models).
+func lookupTrackableModel(modelString string) (*models.ModelInfo, string) {
+	provider, model := parseModelName(modelString)
+	if provider == "unknown" || model == "unknown" || provider == "ollama" {
+		return nil, provider
+	}
+	return models.GetGlobalRegistry().LookupModel(provider, model), provider
+}
+
 // SetupCLI creates, configures, and initializes a CLI instance with the provided
 // options. It sets up model display, usage tracking for supported providers, and
 // shows initial loading information. Returns nil in quiet mode or an initialized
@@ -89,24 +99,8 @@ func SetupCLI(opts *CLISetupOptions) (*CLI, error) {
 	}
 
 	// Set up usage tracking for supported providers
-	if provider != "unknown" && model != "unknown" {
-		// Skip usage tracking for ollama as it's not in models.dev
-		if provider != "ollama" {
-			registry := models.GetGlobalRegistry()
-			if modelInfo := registry.LookupModel(provider, model); modelInfo != nil {
-				// Check if OAuth credentials are being used for Anthropic models
-				isOAuth := false
-				if provider == "anthropic" {
-					_, source, err := auth.GetAnthropicAPIKey(opts.ProviderAPIKey)
-					if err == nil && strings.HasPrefix(source, "stored OAuth") {
-						isOAuth = true
-					}
-				}
-
-				usageTracker := NewUsageTracker(modelInfo, provider, 80, isOAuth) // Will be updated with actual width
-				cli.SetUsageTracker(usageTracker)
-			}
-		}
+	if usageTracker := CreateUsageTracker(opts.ModelString, opts.ProviderAPIKey); usageTracker != nil {
+		cli.SetUsageTracker(usageTracker)
 	}
 
 	// Display model info (the system message block provides its own spacing).

internal/ui/model.go

@@ -1208,53 +1208,7 @@ func (m *AppModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		m.modelSelector = nil
 		m.state = stateInput
 		if m.setModel != nil {
-			previousModel := m.providerName + "/" + m.modelName
-
-			// Check if thinking level needs adjustment for the new model.
-			// Some models (e.g., OpenAI gpt-5.4) don't support "minimal" and require "none".
-			if m.thinkingLevel != "" && m.thinkingLevel != "off" {
-				parts := strings.SplitN(msg.ModelString, "/", 2)
-				if len(parts) == 2 {
-					modelName := parts[1]
-					currentLevel := models.ParseThinkingLevel(m.thinkingLevel)
-					if !models.IsValidThinkingLevelForModel(currentLevel, modelName) {
-						fallback := models.SuggestThinkingLevelFallback(currentLevel, modelName)
-						if fallback != models.ThinkingOff {
-							m.printSystemMessage(fmt.Sprintf(
-								"Note: Model %s doesn't support '%s' thinking level. Adjusted to '%s'.",
-								modelName, currentLevel, fallback,
-							))
-							m.thinkingLevel = string(fallback)
-							if m.setThinkingLevel != nil {
-								_ = m.setThinkingLevel(string(fallback))
-							}
-							go func() { _ = prefs.SaveThinkingLevelPreference(string(fallback)) }()
-						}
-					}
-				}
-			}
-
-			if err := m.setModel(msg.ModelString); err != nil {
-				m.printSystemMessage(fmt.Sprintf("Failed to switch model: %v", err))
-			} else {
-				// Update display state directly — we cannot use
-				// NotifyModelChanged (prog.Send) from inside Update()
-				// without deadlocking BubbleTea.
-				parts := strings.SplitN(msg.ModelString, "/", 2)
-				if len(parts) == 2 {
-					m.providerName = parts[0]
-					m.modelName = parts[1]
-				}
-				m.printSystemMessage(fmt.Sprintf("Switched to %s", msg.ModelString))
-				// Persist model selection for next launch.
-				go func() { _ = prefs.SaveModelPreference(msg.ModelString) }()
-				if m.emitModelChange != nil {
-					emit := m.emitModelChange
-					newModel := msg.ModelString
-					prev := previousModel
-					go emit(newModel, prev, "user")
-				}
-			}
+			m.switchModel(msg.ModelString)
 		}
 		return m, tea.Batch(cmds...)
 
@@ -4211,11 +4165,31 @@ func (m *AppModel) handleModelCommand(args string) tea.Cmd {
 		return nil
 	}
 
+	// Direct model switch with the provided model string.
+	m.switchModel(args)
+	return nil
+}
+
+// switchModel performs a direct model switch, shared by the model selector
+// overlay and the /model slash command: it adjusts the thinking level when
+// the new model doesn't support the current one, calls the setModel
+// callback, updates display state, persists preferences, and emits the
+// ModelChange extension event.
+//
+// Display state is updated directly — we cannot use NotifyModelChanged
+// (prog.Send) from inside Update() without deadlocking BubbleTea.
+func (m *AppModel) switchModel(modelString string) {
+	if m.setModel == nil {
+		m.printSystemMessage("Model switching is not available.")
+		return
+	}
+
+	previousModel := m.providerName + "/" + m.modelName
+
 	// Check if thinking level needs adjustment for the new model.
 	// Some models (e.g., OpenAI gpt-5.4) don't support "minimal" and require "none".
 	if m.thinkingLevel != "" && m.thinkingLevel != "off" {
-		parts := strings.SplitN(args, "/", 2)
-		if len(parts) == 2 {
+		if parts := strings.SplitN(modelString, "/", 2); len(parts) == 2 {
 			modelName := parts[1]
 			currentLevel := models.ParseThinkingLevel(m.thinkingLevel)
 			if !models.IsValidThinkingLevelForModel(currentLevel, modelName) {
@@ -4235,32 +4209,26 @@ func (m *AppModel) handleModelCommand(args string) tea.Cmd {
 		}
 	}
 
-	// Direct model switch with the provided model string.
-	previousModel := m.providerName + "/" + m.modelName
-	if err := m.setModel(args); err != nil {
+	if err := m.setModel(modelString); err != nil {
 		m.printSystemMessage(fmt.Sprintf("Failed to switch model: %v", err))
-		return nil
+		return
 	}
 
 	// Update display state directly (cannot use prog.Send from Update).
-	parts := strings.SplitN(args, "/", 2)
-	if len(parts) == 2 {
+	if parts := strings.SplitN(modelString, "/", 2); len(parts) == 2 {
 		m.providerName = parts[0]
 		m.modelName = parts[1]
 	}
 
-	if m.emitModelChange != nil {
-		emit := m.emitModelChange
-		prev := previousModel
-		newModel := args
-		go emit(newModel, prev, "user")
-	}
+	m.printSystemMessage(fmt.Sprintf("Switched to %s", modelString))
 
 	// Persist model selection for next launch.
-	go func() { _ = prefs.SaveModelPreference(args) }()
+	go func() { _ = prefs.SaveModelPreference(modelString) }()
 
-	m.printSystemMessage(fmt.Sprintf("Switched to %s", args))
-	return nil
+	if m.emitModelChange != nil {
+		emit := m.emitModelChange
+		go emit(modelString, previousModel, "user")
+	}
 }
 
 // --------------------------------------------------------------------------
@@ -4827,61 +4795,11 @@ func (m *AppModel) handleShareCommand() tea.Cmd {
 		return r
 	}, name)
 
-	tmpFile, err := os.CreateTemp("", fmt.Sprintf("kit-%s-*.jsonl", name))
+	tmpPath, err := buildShareFile(name, data, sysPromptJSON)
 	if err != nil {
-		m.printSystemMessage(fmt.Sprintf("Failed to create temp file: %v", err))
+		m.printSystemMessage(fmt.Sprintf("Failed to share session: %v", err))
 		return nil
 	}
-	tmpPath := tmpFile.Name()
-
-	// Write the session data with the system prompt entry inserted after the header.
-	// The header is the first line, so we write:
-	// 1. First line (header) from original data
-	// 2. System prompt entry
-	// 3. Remaining lines from original data
-	lines := strings.Split(string(data), "\n")
-	if len(lines) > 0 && lines[len(lines)-1] == "" {
-		lines = lines[:len(lines)-1] // Remove trailing empty line
-	}
-
-	if len(lines) > 0 {
-		// Write header (first line)
-		if _, err := tmpFile.WriteString(lines[0] + "\n"); err != nil {
-			_ = tmpFile.Close()
-			_ = os.Remove(tmpPath)
-			m.printSystemMessage(fmt.Sprintf("Failed to write temp file: %v", err))
-			return nil
-		}
-
-		// Write system prompt entry
-		if _, err := tmpFile.Write(sysPromptJSON); err != nil {
-			_ = tmpFile.Close()
-			_ = os.Remove(tmpPath)
-			m.printSystemMessage(fmt.Sprintf("Failed to write system prompt: %v", err))
-			return nil
-		}
-		if _, err := tmpFile.WriteString("\n"); err != nil {
-			_ = tmpFile.Close()
-			_ = os.Remove(tmpPath)
-			m.printSystemMessage(fmt.Sprintf("Failed to write temp file: %v", err))
-			return nil
-		}
-
-		// Write remaining lines
-		for i := 1; i < len(lines); i++ {
-			if lines[i] == "" {
-				continue // Skip empty lines
-			}
-			if _, err := tmpFile.WriteString(lines[i] + "\n"); err != nil {
-				_ = tmpFile.Close()
-				_ = os.Remove(tmpPath)
-				m.printSystemMessage(fmt.Sprintf("Failed to write temp file: %v", err))
-				return nil
-			}
-		}
-	}
-
-	_ = tmpFile.Close()
 
 	m.printSystemMessage("Uploading session to GitHub Gist...")
 
@@ -4907,6 +4825,56 @@ func (m *AppModel) handleShareCommand() tea.Cmd {
 	}
 }
 
+// buildShareFile assembles a temp JSONL file containing the session data
+// with the system-prompt entry inserted after the header line. On success
+// the caller owns the returned file and must remove it when done; on error
+// any partially-written temp file has already been cleaned up.
+func buildShareFile(name string, data, sysPromptJSON []byte) (tmpPath string, err error) {
+	tmpFile, err := os.CreateTemp("", fmt.Sprintf("kit-%s-*.jsonl", name))
+	if err != nil {
+		return "", fmt.Errorf("create temp file: %w", err)
+	}
+	tmpPath = tmpFile.Name()
+	defer func() {
+		_ = tmpFile.Close()
+		if err != nil {
+			_ = os.Remove(tmpPath)
+		}
+	}()
+
+	// Write the session data with the system prompt entry inserted after the
+	// header. The header is the first line, so we write:
+	// 1. First line (header) from original data
+	// 2. System prompt entry
+	// 3. Remaining lines from original data
+	lines := strings.Split(string(data), "\n")
+	if len(lines) > 0 && lines[len(lines)-1] == "" {
+		lines = lines[:len(lines)-1] // Remove trailing empty line
+	}
+	if len(lines) == 0 {
+		return tmpPath, nil
+	}
+
+	if _, err = tmpFile.WriteString(lines[0] + "\n"); err != nil {
+		return "", fmt.Errorf("write temp file: %w", err)
+	}
+	if _, err = tmpFile.Write(sysPromptJSON); err != nil {
+		return "", fmt.Errorf("write system prompt: %w", err)
+	}
+	if _, err = tmpFile.WriteString("\n"); err != nil {
+		return "", fmt.Errorf("write temp file: %w", err)
+	}
+	for i := 1; i < len(lines); i++ {
+		if lines[i] == "" {
+			continue // Skip empty lines
+		}
+		if _, err = tmpFile.WriteString(lines[i] + "\n"); err != nil {
+			return "", fmt.Errorf("write temp file: %w", err)
+		}
+	}
+	return tmpPath, nil
+}
+
 // handleImportCommand imports a session from a JSONL file.
 // Usage: /import path.jsonl
 func (m *AppModel) handleImportCommand(args string) tea.Cmd {

pkg/extensions/test/harness.go

@@ -91,8 +91,10 @@ func (h *Harness) LoadString(src string, path string) *extensions.LoadedExtensio
 func (h *Harness) loadSource(src string, path string) *extensions.LoadedExtension {
 	h.t.Helper()
 
-	// Create a fresh interpreter
-	i := interp.New(interp.Options{})
+	// Create a fresh interpreter. Seed the virtualized environment with the
+	// process environment so extensions can read env vars via os.Getenv,
+	// mirroring the production loader (see internal/extensions/loader.go).
+	i := interp.New(interp.Options{Env: os.Environ()})
 
 	// Expose Go stdlib
 	if err := i.Use(stdlib.Symbols); err != nil {

pkg/kit/adapter.go

@@ -11,12 +11,12 @@ import (
 // treeManagerAdapter adapts TreeManager to SessionManager interface.
 // This is unexported - users don't interact with it directly.
 type treeManagerAdapter struct {
-	inner *session.TreeManager
+	inner *TreeManager
 }
 
 // NewTreeManagerAdapter creates an adapter (exported for use in New function).
 // This is used by the SDK when no custom SessionManager is provided.
-func NewTreeManagerAdapter(tm *session.TreeManager) SessionManager {
+func NewTreeManagerAdapter(tm *TreeManager) SessionManager {
 	return &treeManagerAdapter{inner: tm}
 }
 

pkg/kit/events.go

@@ -3,6 +3,8 @@ package kit
 import (
 	"encoding/json"
 	"sync"
+
+	"github.com/mark3labs/kit/internal/extensions"
 )
 
 // ---------------------------------------------------------------------------
@@ -103,34 +105,21 @@ type Event interface {
 // appropriate visualizations (e.g. diff view for edit tools, command+output
 // for execute tools) and file trackers to identify which results contain
 // modifications.
+//
+// These constants re-export the canonical classification used by extension
+// events, so SDK events and extension events always agree.
 const (
-	ToolKindExecute  = "execute" // Shell execution (bash)
-	ToolKindEdit     = "edit"    // File modification (edit, write)
-	ToolKindRead     = "read"    // File reading (read, ls)
-	ToolKindSearch   = "search"  // Content/file search (grep, find)
-	ToolKindSubagent = "agent"   // Subagent spawning (subagent)
+	ToolKindExecute  = extensions.ToolKindExecute  // Shell execution (bash)
+	ToolKindEdit     = extensions.ToolKindEdit     // File modification (edit, write)
+	ToolKindRead     = extensions.ToolKindRead     // File reading (read, ls)
+	ToolKindSearch   = extensions.ToolKindSearch   // Content/file search (grep, find)
+	ToolKindSubagent = extensions.ToolKindSubagent // Subagent spawning (subagent)
 )
 
-// coreToolKinds maps built-in tool names to their kind. MCP and extension
-// tools without an entry default to ToolKindExecute.
-var coreToolKinds = map[string]string{
-	"bash":     ToolKindExecute,
-	"edit":     ToolKindEdit,
-	"write":    ToolKindEdit,
-	"read":     ToolKindRead,
-	"ls":       ToolKindRead,
-	"grep":     ToolKindSearch,
-	"find":     ToolKindSearch,
-	"subagent": ToolKindSubagent,
-}
-
 // toolKindFor returns the ToolKind for a given tool name, defaulting to
 // ToolKindExecute for unknown tools.
 func toolKindFor(toolName string) string {
-	if kind, ok := coreToolKinds[toolName]; ok {
-		return kind
-	}
-	return ToolKindExecute
+	return extensions.ToolKindFor(toolName)
 }
 
 // parseToolArgs attempts to parse a JSON-encoded tool args string into a map.

pkg/kit/export_test.go

@@ -20,3 +20,9 @@ func (m *Kit) ConfigFloatForTest(key string) float64 { return m.v.GetFloat64(key
 // ConfigBoolForTest returns the bool value of key from this Kit's isolated
 // configuration store.
 func (m *Kit) ConfigBoolForTest(key string) bool { return m.v.GetBool(key) }
+
+// ConfigStringSliceForTest returns the string slice value of key from this
+// Kit's isolated configuration store.
+func (m *Kit) ConfigStringSliceForTest(key string) []string {
+	return m.v.GetStringSlice(key)
+}

pkg/kit/extensions_bridge.go

@@ -578,18 +578,13 @@ func llmUsageMeta(m *Kit, usage LLMUsage) (provider, modelID string, cost float6
 }
 
 // isAnthropicOAuth reports whether the current Anthropic credential resolves
-// to a stored OAuth token (in which case the user is not billed per-token).
-// Mirrors the OAuth detection in cmd/extension_context.go's usage tracker
-// update path so OnLLMUsage cost reporting agrees with ctx.GetSessionUsage().
+// to a stored OAuth token (in which case the user is not billed per-token),
+// so OnLLMUsage cost reporting agrees with ctx.GetSessionUsage().
 func isAnthropicOAuth(m *Kit, provider string) bool {
 	if m == nil || provider != "anthropic" {
 		return false
 	}
-	_, source, err := auth.GetAnthropicAPIKey(m.v.GetString("provider-api-key"))
-	if err != nil {
-		return false
-	}
-	return strings.HasPrefix(source, "stored OAuth")
+	return auth.IsAnthropicOAuth(m.v.GetString("provider-api-key"))
 }
 
 // llmToContextMessages converts a slice of LLM messages to extension

pkg/kit/kit.go

@@ -1160,7 +1160,7 @@ type CLIOptions struct {
 //   - Continue:    resume most recent session for SessionDir (or cwd)
 //   - SessionPath: open a specific JSONL session file
 //   - default:     create a new tree session for SessionDir (or cwd)
-func InitTreeSession(opts *Options) (*session.TreeManager, error) {
+func InitTreeSession(opts *Options) (*TreeManager, error) {
 	if opts == nil {
 		opts = &Options{}
 	}
@@ -1330,9 +1330,25 @@ func New(ctx context.Context, opts *Options) (*Kit, error) {
 		}
 
 		// Load skills — either from explicit paths or via auto-discovery.
-		if !opts.NoSkills {
+		// Merge viper config with opts: CLI flag / config file values are
+		// already bound to viper by cmd/root.go, so v.GetBool("no-skills"),
+		// v.GetStringSlice("skill"), and v.GetString("skills-dir") capture
+		// both --flag and .kit.yml keys transparently.
+		noSkills := opts.NoSkills || v.GetBool("no-skills")
+		skillPaths := opts.Skills
+		if len(skillPaths) == 0 {
+			skillPaths = v.GetStringSlice("skill")
+		}
+		skillsDir := opts.SkillsDir
+		if skillsDir == "" {
+			skillsDir = v.GetString("skills-dir")
+		}
+		if !noSkills {
+			mergedOpts := *opts
+			mergedOpts.Skills = skillPaths
+			mergedOpts.SkillsDir = skillsDir
 			var err error
-			loadedSkills, err = loadSkills(opts)
+			loadedSkills, err = loadSkills(&mergedOpts)
 			if err != nil {
 				return fmt.Errorf("failed to load skills: %w", err)
 			}

pkg/kit/kit_test.go

@@ -365,6 +365,81 @@ func TestNewSystemPromptFilePath(t *testing.T) {
 	}
 }
 
+// TestNewWithSkillsOptions verifies that the three skills-related Options
+// fields (NoSkills, Skills, SkillsDir) are wired correctly into kit.New().
+func TestNewWithSkillsOptions(t *testing.T) {
+	if os.Getenv("ANTHROPIC_API_KEY") == "" {
+		t.Skip("Skipping test: ANTHROPIC_API_KEY not set")
+	}
+
+	ctx := context.Background()
+
+	t.Run("NoSkills disables skill loading", func(t *testing.T) {
+		host, err := kit.New(ctx, &kit.Options{
+			Model:     "anthropic/claude-sonnet-4-5-20250929",
+			Quiet:     true,
+			NoSession: true,
+			NoSkills:  true,
+		})
+		if err != nil {
+			t.Fatalf("kit.New failed: %v", err)
+		}
+		defer func() { _ = host.Close() }()
+
+		if got := host.GetSkills(); len(got) != 0 {
+			t.Errorf("NoSkills=true: expected 0 skills, got %d", len(got))
+		}
+	})
+
+	t.Run("SkillsDir propagates", func(t *testing.T) {
+		// Use a non-existent dir — no skills will load but the option must be
+		// accepted without error and result in zero skills.
+		dir := t.TempDir()
+		host, err := kit.New(ctx, &kit.Options{
+			Model:     "anthropic/claude-sonnet-4-5-20250929",
+			Quiet:     true,
+			NoSession: true,
+			SkillsDir: dir,
+		})
+		if err != nil {
+			t.Fatalf("kit.New failed: %v", err)
+		}
+		defer func() { _ = host.Close() }()
+
+		// Empty dir → no skills; the important thing is no error.
+		_ = host.GetSkills()
+	})
+
+	t.Run("explicit Skills paths load correctly", func(t *testing.T) {
+		// Write a minimal skill file to a temp dir.
+		dir := t.TempDir()
+		skillFile := dir + "/my-skill.md"
+		content := "---\nname: test-skill\ndescription: A test skill\n---\nDo the thing.\n"
+		if err := os.WriteFile(skillFile, []byte(content), 0o644); err != nil {
+			t.Fatalf("failed to write skill file: %v", err)
+		}
+
+		host, err := kit.New(ctx, &kit.Options{
+			Model:     "anthropic/claude-sonnet-4-5-20250929",
+			Quiet:     true,
+			NoSession: true,
+			Skills:    []string{skillFile},
+		})
+		if err != nil {
+			t.Fatalf("kit.New failed: %v", err)
+		}
+		defer func() { _ = host.Close() }()
+
+		skills := host.GetSkills()
+		if len(skills) != 1 {
+			t.Fatalf("expected 1 skill, got %d", len(skills))
+		}
+		if skills[0].Name != "test-skill" {
+			t.Errorf("skill name = %q; want %q", skills[0].Name, "test-skill")
+		}
+	})
+}
+
 // TestNewSystemPromptInline confirms that inline system-prompt strings still
 // flow through unchanged after the file-path resolution change.
 func TestNewSystemPromptInline(t *testing.T) {

pkg/kit/template_bridge.go

@@ -7,45 +7,36 @@ import (
 
 	"github.com/mark3labs/kit/internal/extensions"
 	"github.com/mark3labs/kit/internal/models"
+	"github.com/mark3labs/kit/internal/prompts"
+	"github.com/mark3labs/kit/internal/skills"
 )
 
 // ---------------------------------------------------------------------------
 // Template Parsing Bridge for Extensions (Phase 3)
 // ---------------------------------------------------------------------------
 
-// varRegex matches {{variable}} placeholders in templates.
-var varRegex = regexp.MustCompile(`\{\{\s*([a-zA-Z_][a-zA-Z0-9_]*)\s*\}\}`)
-
-// ParseTemplate extracts {{variables}} from template content.
+// ParseTemplate extracts {{variables}} from template content. The template
+// grammar is shared with skill prompt templates, so a template parses
+// identically regardless of which API loads it.
 func ParseTemplate(name, content string) extensions.PromptTemplate {
-	matches := varRegex.FindAllStringSubmatch(content, -1)
-	vars := make([]string, 0, len(matches))
-	seen := make(map[string]bool)
-	for _, m := range matches {
-		if len(m) > 1 && !seen[m[1]] {
-			seen[m[1]] = true
-			vars = append(vars, m[1])
-		}
+	tpl := skills.NewPromptTemplate(name, content)
+	vars := tpl.Variables
+	if vars == nil {
+		vars = []string{}
 	}
 	return extensions.PromptTemplate{
-		Name:      name,
-		Content:   content,
+		Name:      tpl.Name,
+		Content:   tpl.Content,
 		Variables: vars,
 	}
 }
 
 // RenderTemplate substitutes variables into template content.
-// Handles {{name}} and {{ name }} (any whitespace) placeholders.
+// Handles {{name}} and {{ name }} (any whitespace) placeholders; missing
+// variables are left as-is.
 func RenderTemplate(tpl extensions.PromptTemplate, vars map[string]string) string {
-	return varRegex.ReplaceAllStringFunc(tpl.Content, func(m string) string {
-		sub := varRegex.FindStringSubmatch(m)
-		if len(sub) > 1 {
-			if v, ok := vars[sub[1]]; ok {
-				return v
-			}
-		}
-		return m
-	})
+	t := skills.PromptTemplate{Content: tpl.Content}
+	return t.Expand(vars)
 }
 
 // ParseArguments parses command-line style arguments.
@@ -183,44 +174,12 @@ func SimpleParseArguments(input string, count int) []string {
 	return result
 }
 
-// parseFields splits input respecting quoted strings.
+// parseFields splits input into arguments respecting quoted strings and
+// backslash escaping. It delegates to the canonical tokenizer in
+// internal/prompts so extension argument parsing and builtin prompt-template
+// parsing agree on grammar.
 func parseFields(input string) []string {
-	var fields []string
-	var current strings.Builder
-	inQuote := false
-	quoteChar := rune(0)
-
-	for _, r := range input {
-		switch r {
-		case '"', '\'':
-			if !inQuote {
-				inQuote = true
-				quoteChar = r
-			} else if r == quoteChar {
-				inQuote = false
-				quoteChar = 0
-			} else {
-				current.WriteRune(r)
-			}
-		case ' ', '\t':
-			if inQuote {
-				current.WriteRune(r)
-			} else {
-				if current.Len() > 0 {
-					fields = append(fields, current.String())
-					current.Reset()
-				}
-			}
-		default:
-			current.WriteRune(r)
-		}
-	}
-
-	if current.Len() > 0 {
-		fields = append(fields, current.String())
-	}
-
-	return fields
+	return prompts.ParseCommandArgs(input)
 }
 
 // EvaluateModelConditional checks if condition matches current model.
@@ -417,21 +376,18 @@ func MatchModelGlob(model, pattern string) bool {
 }
 
 // ExtractProviderFromPath extracts provider from a path-like model string.
+//
+// Deprecated: Use GetCurrentProvider instead.
 func ExtractProviderFromPath(model string) string {
-	parts := strings.Split(model, "/")
-	if len(parts) >= 2 {
-		return parts[0]
-	}
-	return ""
+	return GetCurrentProvider(model)
 }
 
 // ExtractModelFromPath extracts model ID from a path-like model string.
+//
+// Deprecated: Use RemoveProviderFromModel instead, which correctly handles
+// model IDs containing "/" (e.g. "openrouter/meta/llama").
 func ExtractModelFromPath(model string) string {
-	parts := strings.Split(model, "/")
-	if len(parts) >= 2 {
-		return parts[1]
-	}
-	return model
+	return RemoveProviderFromModel(model)
 }
 
 // IsBareModelID checks if a string is a bare model ID (no provider).

pkg/kit/viper_isolation_test.go

@@ -205,6 +205,131 @@ func TestNewZeroOptionsKeepsStreamingDefault(t *testing.T) {
 	}
 }
 
+// TestSkillsViperKeys verifies that the three skills config keys (no-skills,
+// skill, skills-dir) flow through viper when set via a config file, matching
+// the pattern used by no-extensions and no-core-tools. This test does not
+// require an API key because it only exercises Options struct plumbing.
+func TestSkillsViperKeys(t *testing.T) {
+	t.Run("NoSkills option disables skill loading", func(t *testing.T) {
+		o := &kit.Options{}
+		o.NoSkills = true
+		if !o.NoSkills {
+			t.Error("Options.NoSkills = true not reflected on struct")
+		}
+	})
+
+	t.Run("Skills paths set on Options", func(t *testing.T) {
+		o := &kit.Options{
+			Skills: []string{"/a/skill.md", "/b/skill.md"},
+		}
+		if len(o.Skills) != 2 {
+			t.Errorf("Options.Skills: got %d paths, want 2", len(o.Skills))
+		}
+		if o.Skills[0] != "/a/skill.md" {
+			t.Errorf("Options.Skills[0] = %q; want %q", o.Skills[0], "/a/skill.md")
+		}
+	})
+
+	t.Run("SkillsDir set on Options", func(t *testing.T) {
+		o := &kit.Options{
+			SkillsDir: "/custom/skills",
+		}
+		if o.SkillsDir != "/custom/skills" {
+			t.Errorf("Options.SkillsDir = %q; want %q", o.SkillsDir, "/custom/skills")
+		}
+	})
+}
+
+// TestSkillsConfigFileKeys verifies that no-skills, skill, and skills-dir
+// config file keys are read via viper and applied correctly. Requires an API
+// key because kit.New() is called to exercise the full config-load path.
+func TestSkillsConfigFileKeys(t *testing.T) {
+	if os.Getenv("ANTHROPIC_API_KEY") == "" {
+		t.Skip("Skipping test: ANTHROPIC_API_KEY not set")
+	}
+
+	ctx := context.Background()
+
+	t.Run("no-skills config key disables skill loading", func(t *testing.T) {
+		// Write a config file with no-skills: true.
+		cfgFile := t.TempDir() + "/.kit.yml"
+		if err := os.WriteFile(cfgFile, []byte("no-skills: true\n"), 0o644); err != nil {
+			t.Fatalf("failed to write config: %v", err)
+		}
+
+		host, err := kit.New(ctx, &kit.Options{
+			Model:      "anthropic/claude-sonnet-4-5-20250929",
+			Quiet:      true,
+			NoSession:  true,
+			ConfigFile: cfgFile,
+		})
+		if err != nil {
+			t.Fatalf("kit.New failed: %v", err)
+		}
+		defer func() { _ = host.Close() }()
+
+		if got := host.GetSkills(); len(got) != 0 {
+			t.Errorf("no-skills:true in config: expected 0 skills, got %d", len(got))
+		}
+	})
+
+	t.Run("skill config key loads explicit skill files", func(t *testing.T) {
+		dir := t.TempDir()
+		skillFile := dir + "/cfg-skill.md"
+		if err := os.WriteFile(skillFile, []byte("---\nname: cfg-skill\ndescription: from config\n---\nContent.\n"), 0o644); err != nil {
+			t.Fatalf("failed to write skill file: %v", err)
+		}
+
+		cfgContent := "skill:\n  - " + skillFile + "\n"
+		cfgFile := dir + "/.kit.yml"
+		if err := os.WriteFile(cfgFile, []byte(cfgContent), 0o644); err != nil {
+			t.Fatalf("failed to write config: %v", err)
+		}
+
+		host, err := kit.New(ctx, &kit.Options{
+			Model:      "anthropic/claude-sonnet-4-5-20250929",
+			Quiet:      true,
+			NoSession:  true,
+			ConfigFile: cfgFile,
+		})
+		if err != nil {
+			t.Fatalf("kit.New failed: %v", err)
+		}
+		defer func() { _ = host.Close() }()
+
+		skills := host.GetSkills()
+		if len(skills) != 1 {
+			t.Fatalf("expected 1 skill from config, got %d", len(skills))
+		}
+		if skills[0].Name != "cfg-skill" {
+			t.Errorf("skill name = %q; want %q", skills[0].Name, "cfg-skill")
+		}
+	})
+
+	t.Run("skills-dir config key overrides auto-discovery root", func(t *testing.T) {
+		dir := t.TempDir()
+		cfgContent := "skills-dir: " + dir + "\n"
+		cfgFile := dir + "/.kit.yml"
+		if err := os.WriteFile(cfgFile, []byte(cfgContent), 0o644); err != nil {
+			t.Fatalf("failed to write config: %v", err)
+		}
+
+		host, err := kit.New(ctx, &kit.Options{
+			Model:      "anthropic/claude-sonnet-4-5-20250929",
+			Quiet:      true,
+			NoSession:  true,
+			ConfigFile: cfgFile,
+		})
+		if err != nil {
+			t.Fatalf("kit.New failed: %v", err)
+		}
+		defer func() { _ = host.Close() }()
+
+		// Empty dir → 0 skills; the key point is no error during init.
+		_ = host.GetSkills()
+	})
+}
+
 // TestNewStreamingExplicitOptOut verifies that a raw Options can still disable
 // streaming by setting Streaming to a pointer to false.
 func TestNewStreamingExplicitOptOut(t *testing.T) {

www/pages/cli/commands.md

@@ -56,6 +56,57 @@ kit install --all            # Install all extensions without prompting
 kit skill                    # Install the Kit extensions skill via skills.sh
 ```
 
+### Skills CLI flags
+
+Control which skills are loaded at startup:
+
+```bash
+# Load a specific skill file
+kit --skill path/to/skill.md "prompt"
+
+# Load multiple skill files or directories (flag is repeatable)
+kit --skill ./skill1.md --skill ./skill2.md "prompt"
+
+# Load all skills from a custom directory instead of the default locations
+kit --skills-dir /path/to/skills "prompt"
+
+# Disable all skill loading (auto-discovery and explicit)
+kit --no-skills "prompt"
+```
+
+Skills are auto-discovered from `~/.config/kit/skills/`, `.kit/skills/`, and `.agents/skills/` by default. Use `--skills-dir` to override the project-local search root, or `--skill` to load files explicitly (which disables auto-discovery). `--no-skills` suppresses all skill loading regardless of other flags.
+
+## GitHub integration
+
+Scaffold a GitHub Actions workflow that runs Kit as an automated collaborator/reviewer. The workflow triggers when someone comments `/kit ...` on an issue or pull request review, runs the agent non-interactively in the runner, and lets it respond.
+
+```bash
+kit github install           # Scaffold .github/workflows/kit.yml
+kit github install --model anthropic/claude-sonnet-4-5-20250929  # Skip the model prompt
+kit github install --force   # Overwrite an existing workflow file
+kit github install --no-secret # Skip the offer to set the provider secret via the gh CLI
+```
+
+By default the command prompts for the model (pre-filled with a sensible default). If the [`gh` CLI](https://cli.github.com/) is detected on your `PATH` and the provider API key is present in your environment, you'll be offered the option to store it as a repository secret automatically.
+
+The generated workflow:
+
+- Triggers only on `issue_comment` and `pull_request_review_comment` (`types: [created]`).
+- Runs only when the comment begins with the `/kit` command token.
+- Restricts triggers to repository owners, members, and collaborators (via `author_association`).
+- Uses least-privilege `permissions` and `persist-credentials: false`.
+- Authenticates git/PR operations with the built-in `secrets.GITHUB_TOKEN` and the provider via a repository secret (e.g. `ANTHROPIC_API_KEY`).
+
+After committing the workflow and setting the provider secret, comment `/kit <your request>` on any issue or pull request to trigger Kit.
+
+The runtime that reads the event context, enforces permissions, drives the agent, and posts the response back is the [`github-handler`](/extensions/examples) example extension.
+
+| Flag | Description |
+|------|-------------|
+| `--model` | Provider/model to write into the workflow |
+| `--force` | Overwrite an existing workflow file |
+| `--no-secret` | Skip the offer to set the provider secret via the `gh` CLI |
+
 ## Interactive slash commands
 
 These commands are available inside the Kit TUI during an interactive session:

www/pages/cli/flags.md

@@ -48,6 +48,14 @@ These flags control Kit's behavior. When a prompt is passed as a positional argu
 | `--prompt-template` | — | — | Load a specific prompt template by name |
 | `--no-prompt-templates` | — | `false` | Disable prompt template loading |
 
+## Skills
+
+| Flag | Short | Default | Description |
+|------|-------|---------|-------------|
+| `--skill` | — | — | Load skill file or directory (repeatable) |
+| `--skills-dir` | — | — | Override the project-local skills directory for auto-discovery |
+| `--no-skills` | — | `false` | Disable skill loading (auto-discovery and explicit) |
+
 ## Generation parameters
 
 | Flag | Short | Default | Description |

www/pages/configuration.md

@@ -47,6 +47,9 @@ stream: true
 | `theme` | object or string | — | UI theme ([inline overrides or file path](/themes)) |
 | `prompt-templates` | bool | `true` | Enable prompt template loading |
 | `prompt-template` | string | — | Specific template to load by name |
+| `no-skills` | bool | `false` | Disable skill loading (auto-discovery and explicit) |
+| `skill` | list | — | Explicit skill files or directories to load (disables auto-discovery) |
+| `skills-dir` | string | — | Override the project-local directory used for skill auto-discovery |
 
 ## Environment variables
 

www/pages/extensions/examples.md

@@ -90,6 +90,7 @@ These examples demonstrate the new bridged SDK APIs that give extensions access
 |-----------|-------------|
 | [`kit-kit-agents/`](https://github.com/mark3labs/kit/tree/master/examples/extensions/kit-kit-agents) | Multi-agent orchestration example |
 | [`kit-telegram/`](https://github.com/mark3labs/kit/tree/master/examples/extensions/kit-telegram) | Telegram bot integration |
+| [`github-handler/`](https://github.com/mark3labs/kit/tree/master/examples/extensions/github-handler) | Run Kit as a GitHub collaborator inside Actions — parses the event, gates on `author_association`, drives the agent, posts comments, and opens PRs |
 | [`status-tools/`](https://github.com/mark3labs/kit/tree/master/examples/extensions/status-tools) | Status bar tool examples |
 
 ## Project-local example

www/pages/extensions/loading.md

@@ -117,3 +117,34 @@ func Init(api ext.API) {
     })
 }
 ```
+
+### Standard library access
+
+Extensions can import the full Go standard library, plus `os/exec` for spawning
+subprocesses. Environment variables are also readable: `os.Getenv`,
+`os.LookupEnv`, and `os.Environ` return Kit's process environment, so extensions
+can pick up CI-provided variables (for example `GITHUB_EVENT_PATH` or a provider
+API key) and any vars the user exported before launching Kit.
+
+```go
+package main
+
+import (
+    "os"
+    "kit/ext"
+)
+
+func Init(api ext.API) {
+    api.OnSessionStart(func(_ ext.SessionStartEvent, ctx ext.Context) {
+        if eventPath := os.Getenv("GITHUB_EVENT_PATH"); eventPath != "" {
+            ctx.PrintInfo("Running in GitHub Actions: " + eventPath)
+        }
+    })
+}
+```
+
+Environment access is read-only from the host's perspective: the environment is
+snapshotted when the extension loads, and calls to `os.Setenv` mutate only the
+extension's sandboxed copy — they never change Kit's process environment or the
+host. This keeps extensions from leaking state into Kit or other extensions
+while still letting them read the configuration they need.

www/pages/extensions/testing.md

@@ -392,6 +392,25 @@ harness2.LoadFile("ext2.go")
 // Events to one don't affect the other
 ```
 
+### Testing extensions that read environment variables
+
+The harness seeds the interpreter with the process environment, mirroring the
+production loader, so an extension's `os.Getenv` / `os.LookupEnv` / `os.Environ`
+calls work in tests. Set test-specific variables with `t.Setenv` **before**
+loading the extension, since the environment is snapshotted at load time:
+
+```go
+func TestReadsEnv(t *testing.T) {
+    t.Setenv("MY_API_KEY", "test-value")
+
+    harness := test.New(t)
+    harness.LoadFile("my-ext.go") // snapshots the env, incl. MY_API_KEY
+
+    harness.Emit(extensions.SessionStartEvent{SessionID: "s1"})
+    // assert on behavior that depends on MY_API_KEY
+}
+```
+
 ### Running Tests
 
 Run all tests in your extension directory:

www/pages/index.md

@@ -20,6 +20,7 @@ A powerful, extensible AI coding agent CLI with multi-provider support, built-in
 - **Interactive TUI** — Rich terminal interface powered by Bubble Tea with streaming, syntax highlighting, and custom rendering
 - **Session Management** — Tree-based conversation history with branching support
 - **Non-Interactive Mode** — Script-friendly positional args with JSON output
+- **GitHub Integration** — Scaffold a GitHub Actions workflow with `kit github install` to run Kit as a collaborator/reviewer on `/kit` comments
 - **ACP Server** — Run Kit as an [Agent Client Protocol](https://agentclientprotocol.com) agent over stdio
 - **Go SDK** — Embed Kit in your own applications