chore(deps): update dependencies

- bump mcp-go to v0.47.1 - update cloud auth, otel, and various indirect deps
feat(session): make compaction create new leaf with no parent
2026-06-18 13:25:52 +00:00 · 2026-04-08 20:51:59 +03:00 · 2026-04-08 18:52:44 +03:00 · 2026-04-08 16:55:53 +03:00 · 2026-04-08 15:15:27 +03:00 · 2026-04-08 15:04:48 +03:00
37 changed files with 2272 additions and 499 deletions
@@ -531,7 +531,12 @@ host, err := kit.New(ctx, &kit.Options{
    NoSession:    true,                // Ephemeral mode

    // Tool options
-    ExtraTools:   []kit.Tool{...},     // Additional tools alongside defaults
+    Tools:            []kit.Tool{...},     // Replace default tool set entirely
+    ExtraTools:       []kit.Tool{...},     // Add tools alongside defaults
+    DisableCoreTools: true,                // Use no core tools (0 tools, for chat-only)
+
+    // Configuration
+    SkipConfig:   true,                   // Skip .kit.yml files (viper defaults + env vars still apply)

    // Compaction
    AutoCompact:  true,                // Auto-compact near context limit
@@ -540,6 +545,28 @@ host, err := kit.New(ctx, &kit.Options{
 })
 ```

+### Custom Tools
+
+Create custom tools with automatic schema generation — no external dependencies needed:
+
+```go
+type SearchInput struct {
+    Query string `json:"query" description:"Search query"`
+}
+
+searchTool := kit.NewTool("search", "Search the codebase",
+    func(ctx context.Context, input SearchInput) (kit.ToolOutput, error) {
+        return kit.TextResult("Found: ..."), nil
+    },
+)
+
+host, _ := kit.New(ctx, &kit.Options{
+    ExtraTools: []kit.Tool{searchTool}, // adds alongside built-in tools
+})
+```
+
+Use `kit.NewParallelTool` for tools safe to run concurrently. See the [SDK docs](/sdk/overview) for full details on struct tags, `ToolOutput` fields, and `ToolCallIDFromContext`.
+
 ### With Callbacks

 ```go
@@ -2003,6 +2003,18 @@ func writeJSONError(err error) {
 //
 // SetupCLI is not used for interactive mode; the TUI (AppModel) handles its own rendering.
 func runInteractiveModeBubbleTea(_ context.Context, appInstance *app.App, modelName, providerName, loadingMessage string, serverNames, toolNames []string, mcpToolCount, extensionToolCount int, usageTracker *ui.UsageTracker, extCommands []commands.ExtensionCommand, promptTemplates []*prompts.PromptTemplate, contextPaths []string, skillItems []ui.SkillItem, getPromptTemplates func() []*prompts.PromptTemplate, getSkillItems func() []ui.SkillItem, getToolNames func() []string, getMCPToolCount func() int, getWidgets func(string) []ui.WidgetData, getHeader, getFooter func() *ui.WidgetData, getToolRenderer func(string) *ui.ToolRendererData, getEditorInterceptor func() *ui.EditorInterceptor, getUIVisibility func() *ui.UIVisibility, getStatusBarEntries func() []ui.StatusBarEntryData, emitBeforeFork func(string, bool, string) (bool, string), emitBeforeSessionSwitch func(string) (bool, string), getGlobalShortcuts func() map[string]func(), getExtensionCommands func() []commands.ExtensionCommand, setModel func(string) error, emitModelChange func(string, string, string), isReasoningModel bool, thinkingLevel string, setThinkingLevel func(string) error, switchSession func(string) error, reloadExtensions func() error, startupExtensionMessages []string) error {
+	// Redirect all log output (stdlib and charm) to a file so that log
+	// messages don't write to stderr and corrupt the TUI. Bubble Tea
+	// captures stdout for rendering; any stray stderr output from
+	// background goroutines (watchers, extension handlers, SDK internals)
+	// will visually corrupt the terminal.
+	logDir := filepath.Join(os.TempDir(), "kit")
+	_ = os.MkdirAll(logDir, 0o700)
+	logFile, logErr := tea.LogToFile(filepath.Join(logDir, "kit.log"), "kit")
+	if logErr == nil {
+		defer func() { _ = logFile.Close() }()
+	}
+
 	// Determine terminal size; fall back gracefully.
 	termWidth, termHeight, err := term.GetSize(int(os.Stdout.Fd()))
 	if err != nil || termWidth == 0 {
@@ -21,7 +21,7 @@ require (
 	github.com/fsnotify/fsnotify v1.9.0
 	github.com/indaco/herald v0.13.0
 	github.com/indaco/herald-md v0.3.0
-	github.com/mark3labs/mcp-go v0.47.0
+	github.com/mark3labs/mcp-go v0.47.1
 	github.com/spf13/cobra v1.10.2
 	github.com/spf13/viper v1.21.0
 	github.com/traefik/yaegi v0.16.1
@@ -31,7 +31,7 @@ require (

 require (
 	cloud.google.com/go v0.123.0 // indirect
-	cloud.google.com/go/auth v0.19.0 // indirect
+	cloud.google.com/go/auth v0.20.0 // indirect
 	cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
 	cloud.google.com/go/compute/metadata v0.9.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.21.0 // indirect
@@ -58,9 +58,9 @@ require (
 	github.com/charmbracelet/harmonica v0.2.0 // indirect
 	github.com/charmbracelet/lipgloss v1.1.1-0.20250404203927-76690c660834 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.15 // indirect
-	github.com/charmbracelet/x/exp/charmtone v0.0.0-20260330094520-2dce04b6f8a4 // indirect
+	github.com/charmbracelet/x/exp/charmtone v0.0.0-20260406091427-a791e22d5143 // indirect
 	github.com/charmbracelet/x/exp/ordered v0.1.0 // indirect
-	github.com/charmbracelet/x/exp/slice v0.0.0-20260330094520-2dce04b6f8a4 // indirect
+	github.com/charmbracelet/x/exp/slice v0.0.0-20260406091427-a791e22d5143 // indirect
 	github.com/charmbracelet/x/exp/strings v0.1.0 // indirect
 	github.com/charmbracelet/x/json v0.2.0 // indirect
 	github.com/charmbracelet/x/termios v0.1.1 // indirect
@@ -81,7 +81,7 @@ require (
 	github.com/googleapis/enterprise-certificate-proxy v0.3.14 // indirect
 	github.com/googleapis/gax-go/v2 v2.21.0 // indirect
 	github.com/gorilla/websocket v1.5.3 // indirect
-	github.com/kaptinlin/go-i18n v0.3.0 // indirect
+	github.com/kaptinlin/go-i18n v0.3.1 // indirect
 	github.com/kaptinlin/jsonpointer v0.4.17 // indirect
 	github.com/kaptinlin/jsonschema v0.7.7 // indirect
 	github.com/kaptinlin/messageformat-go v0.4.19 // indirect
@@ -103,8 +103,8 @@ require (
 	github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
 	github.com/yuin/goldmark v1.8.2 // indirect
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
-	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.67.0 // indirect
-	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.67.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.68.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.68.0 // indirect
 	go.opentelemetry.io/otel v1.43.0 // indirect
 	go.opentelemetry.io/otel/metric v1.43.0 // indirect
 	go.opentelemetry.io/otel/trace v1.43.0 // indirect
@@ -114,9 +114,9 @@ require (
 	golang.org/x/net v0.52.0 // indirect
 	golang.org/x/oauth2 v0.36.0 // indirect
 	golang.org/x/time v0.15.0 // indirect
-	google.golang.org/api v0.274.0 // indirect
+	google.golang.org/api v0.275.0 // indirect
 	google.golang.org/genai v1.52.1 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20260401024825-9d38bb4040a9 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20260406210006-6f92a3bedf2d // indirect
 	google.golang.org/grpc v1.80.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
@@ -128,13 +128,13 @@ require (
 	github.com/charmbracelet/x/term v0.2.2 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.4.0 // indirect
-	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/mattn/go-runewidth v0.0.22 // indirect
+	github.com/mattn/go-isatty v0.0.21 // indirect
+	github.com/mattn/go-runewidth v0.0.23 // indirect
 	github.com/muesli/cancelreader v0.2.2 // indirect
 	github.com/muesli/termenv v0.16.0 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/spf13/pflag v1.0.10 // indirect
 	golang.org/x/sync v0.20.0 // indirect
-	golang.org/x/sys v0.42.0 // indirect
+	golang.org/x/sys v0.43.0 // indirect
 	golang.org/x/text v0.35.0
 )
@@ -10,8 +10,8 @@ charm.land/lipgloss/v2 v2.0.2 h1:xFolbF8JdpNkM2cEPTfXEcW1p6NRzOWTSamRfYEw8cs=
 charm.land/lipgloss/v2 v2.0.2/go.mod h1:KjPle2Qd3YmvP1KL5OMHiHysGcNwq6u83MUjYkFvEkM=
 cloud.google.com/go v0.123.0 h1:2NAUJwPR47q+E35uaJeYoNhuNEM9kM8SjgRgdeOJUSE=
 cloud.google.com/go v0.123.0/go.mod h1:xBoMV08QcqUGuPW65Qfm1o9Y4zKZBpGS+7bImXLTAZU=
-cloud.google.com/go/auth v0.19.0 h1:DGYwtbcsGsT1ywuxsIoWi1u/vlks0moIblQHgSDgQkQ=
-cloud.google.com/go/auth v0.19.0/go.mod h1:2Aph7BT2KnaSFOM0JDPyiYgNh6PL9vGMiP8CUIXZ+IY=
+cloud.google.com/go/auth v0.20.0 h1:kXTssoVb4azsVDoUiF8KvxAqrsQcQtB53DcSgta74CA=
+cloud.google.com/go/auth v0.20.0/go.mod h1:942/yi/itH1SsmpyrbnTMDgGfdy2BUqIKyd0cyYLc5Q=
 cloud.google.com/go/auth/oauth2adapt v0.2.8 h1:keo8NaayQZ6wimpNSmW5OPc283g65QNIiLpZnkHRbnc=
 cloud.google.com/go/auth/oauth2adapt v0.2.8/go.mod h1:XQ9y31RkqZCcwJWNSx2Xvric3RrU88hAYYbjDWYDL+c=
 cloud.google.com/go/compute/metadata v0.9.0 h1:pDUj4QMoPejqq20dK0Pg2N4yG9zIkYGdBtwLoEkH9Zs=
@@ -96,14 +96,14 @@ github.com/charmbracelet/x/conpty v0.1.1 h1:s1bUxjoi7EpqiXysVtC+a8RrvPPNcNvAjfi4
 github.com/charmbracelet/x/conpty v0.1.1/go.mod h1:OmtR77VODEFbiTzGE9G1XiRJAga6011PIm4u5fTNZpk=
 github.com/charmbracelet/x/errors v0.0.0-20240508181413-e8d8b6e2de86 h1:JSt3B+U9iqk37QUU2Rvb6DSBYRLtWqFqfxf8l5hOZUA=
 github.com/charmbracelet/x/errors v0.0.0-20240508181413-e8d8b6e2de86/go.mod h1:2P0UgXMEa6TsToMSuFqKFQR+fZTO9CNGUNokkPatT/0=
-github.com/charmbracelet/x/exp/charmtone v0.0.0-20260330094520-2dce04b6f8a4 h1:pIj18ZCZO4WOVj7jwjLoUb1lC7rS/I8oC3fZWXugNaY=
-github.com/charmbracelet/x/exp/charmtone v0.0.0-20260330094520-2dce04b6f8a4/go.mod h1:nsExn0DGyX0lh9LwLHTn2Gg+hafdzfSXnC+QmEJTZFY=
+github.com/charmbracelet/x/exp/charmtone v0.0.0-20260406091427-a791e22d5143 h1:zmBor0ftFNqVFp9U59ZoEDRUCIYSGOGSIfGGkNZRufs=
+github.com/charmbracelet/x/exp/charmtone v0.0.0-20260406091427-a791e22d5143/go.mod h1:nsExn0DGyX0lh9LwLHTn2Gg+hafdzfSXnC+QmEJTZFY=
 github.com/charmbracelet/x/exp/golden v0.0.0-20250806222409-83e3a29d542f h1:pk6gmGpCE7F3FcjaOEKYriCvpmIN4+6OS/RD0vm4uIA=
 github.com/charmbracelet/x/exp/golden v0.0.0-20250806222409-83e3a29d542f/go.mod h1:IfZAMTHB6XkZSeXUqriemErjAWCCzT0LwjKFYCZyw0I=
 github.com/charmbracelet/x/exp/ordered v0.1.0 h1:55/qLwjIh0gL0Vni+QAWk7T/qRVP6sBf+2agPBgnOFE=
 github.com/charmbracelet/x/exp/ordered v0.1.0/go.mod h1:5UHwmG+is5THxMyCJHNPCn2/ecI07aKNrW+LcResjJ8=
-github.com/charmbracelet/x/exp/slice v0.0.0-20260330094520-2dce04b6f8a4 h1:VSd4zShIAf/4FgEDFJpapEcAPrc7h3dyyN7V9JlJpQw=
-github.com/charmbracelet/x/exp/slice v0.0.0-20260330094520-2dce04b6f8a4/go.mod h1:vqEfX6xzqW1pKKZUUiFOKg0OQ7bCh54Q2vR/tserrRA=
+github.com/charmbracelet/x/exp/slice v0.0.0-20260406091427-a791e22d5143 h1:aEppolah2k9c0LzKX2fk5ryuyQ0Lq8kCOjkvMw1b8o4=
+github.com/charmbracelet/x/exp/slice v0.0.0-20260406091427-a791e22d5143/go.mod h1:vqEfX6xzqW1pKKZUUiFOKg0OQ7bCh54Q2vR/tserrRA=
 github.com/charmbracelet/x/exp/strings v0.1.0 h1:i69S2XI7uG1u4NLGeJPSYU++Nmjvpo9nwd6aoEm7gkA=
 github.com/charmbracelet/x/exp/strings v0.1.0/go.mod h1:/ehtMPNh9K4odGFkqYJKpIYyePhdp1hLBRvyY4bWkH8=
 github.com/charmbracelet/x/json v0.2.0 h1:DqB+ZGx2h+Z+1s98HOuOyli+i97wsFQIxP2ZQANTPrQ=
@@ -185,8 +185,8 @@ github.com/indaco/herald v0.13.0 h1:+xVG9Fx5NpuWhwku/9IlRL6I009NnX4VUGKvlZHTRxU=
 github.com/indaco/herald v0.13.0/go.mod h1:T5g1+XLYvpjouhzAGHnAHDCKizhESkoV6+QPZ3DhgWA=
 github.com/indaco/herald-md v0.3.0 h1:hN1cKyrexPPM9PeHBsKuaWvIizSi/iYvM9yzRgtdb8M=
 github.com/indaco/herald-md v0.3.0/go.mod h1:RUHVaDSG45ymJjKyxpDwBocLXrZo93FB4OeYMsw9B9s=
-github.com/kaptinlin/go-i18n v0.3.0 h1:wP76dvYg04bvwTb+8NB+CmdZ2kL7lSSCQ9B/kFv7QHo=
-github.com/kaptinlin/go-i18n v0.3.0/go.mod h1:pVcu9qsW5pOIOoZFJXesRYmLos1vMQrby70JPAoWmJU=
+github.com/kaptinlin/go-i18n v0.3.1 h1:plXi3XQE1aYamFi8TU0K6actODmw2+5FSobmhTkfQ/0=
+github.com/kaptinlin/go-i18n v0.3.1/go.mod h1:ZRoAHj7elWYamfbv7wev7Ajch6LOzjtBaq8nWe8HIVk=
 github.com/kaptinlin/jsonpointer v0.4.17 h1:mY9k8ciWncxbsECyaxKnR0MdmxamNdp2tLQkAKVrtSk=
 github.com/kaptinlin/jsonpointer v0.4.17/go.mod h1:SsfsjqnHG5zuKo1DTBzk1VknaHlL4osHw+X9kZKukpU=
 github.com/kaptinlin/jsonschema v0.7.7 h1:41BlQJ9dskH0oE5DSzBUrl/w4JQYIr6N6L0B5GNyDoM=
@@ -201,12 +201,12 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/lucasb-eyer/go-colorful v1.4.0 h1:UtrWVfLdarDgc44HcS7pYloGHJUjHV/4FwW4TvVgFr4=
 github.com/lucasb-eyer/go-colorful v1.4.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
-github.com/mark3labs/mcp-go v0.47.0 h1:h44yeM3DduDyQgzImYWu4pt6VRkqP/0p/95AGhWngnA=
-github.com/mark3labs/mcp-go v0.47.0/go.mod h1:JKTC7R2LLVagkEWK7Kwu7DbmA6iIvnNAod6yrHiQMag=
-github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
-github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
-github.com/mattn/go-runewidth v0.0.22 h1:76lXsPn6FyHtTY+jt2fTTvsMUCZq1k0qwRsAMuxzKAk=
-github.com/mattn/go-runewidth v0.0.22/go.mod h1:XBkDxAl56ILZc9knddidhrOlY5R/pDhgLpndooCuJAs=
+github.com/mark3labs/mcp-go v0.47.1 h1:A9sJJ20mscl/ssLYHjodfaoBmq6uuhMG7pAPNYaQymQ=
+github.com/mark3labs/mcp-go v0.47.1/go.mod h1:JKTC7R2LLVagkEWK7Kwu7DbmA6iIvnNAod6yrHiQMag=
+github.com/mattn/go-isatty v0.0.21 h1:xYae+lCNBP7QuW4PUnNG61ffM4hVIfm+zUzDuSzYLGs=
+github.com/mattn/go-isatty v0.0.21/go.mod h1:ZXfXG4SQHsB/w3ZeOYbR0PrPwLy+n6xiMrJlRFqopa4=
+github.com/mattn/go-runewidth v0.0.23 h1:7ykA0T0jkPpzSvMS5i9uoNn2Xy3R383f9HDx3RybWcw=
+github.com/mattn/go-runewidth v0.0.23/go.mod h1:XBkDxAl56ILZc9knddidhrOlY5R/pDhgLpndooCuJAs=
 github.com/mitchellh/hashstructure/v2 v2.0.2 h1:vGKWl0YJqUNxE8d+h8f6NJLcCJrgbhC4NcD46KavDd4=
 github.com/mitchellh/hashstructure/v2 v2.0.2/go.mod h1:MG3aRVU/N29oo/V/IhBX8GR/zz4kQkprJgF2EVszyDE=
 github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELUXHmA=
@@ -272,18 +272,18 @@ github.com/yuin/goldmark v1.8.2 h1:kEGpgqJXdgbkhcOgBxkC0X0PmoPG1ZyoZ117rDVp4zE=
 github.com/yuin/goldmark v1.8.2/go.mod h1:ip/1k0VRfGynBgxOz0yCqHrbZXhcjxyuS66Brc7iBKg=
 go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
 go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
-go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.67.0 h1:yI1/OhfEPy7J9eoa6Sj051C7n5dvpj0QX8g4sRchg04=
-go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.67.0/go.mod h1:NoUCKYWK+3ecatC4HjkRktREheMeEtrXoQxrqYFeHSc=
-go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.67.0 h1:OyrsyzuttWTSur2qN/Lm0m2a8yqyIjUVBZcxFPuXq2o=
-go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.67.0/go.mod h1:C2NGBr+kAB4bk3xtMXfZ94gqFDtg/GkI7e9zqGh5Beg=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.68.0 h1:0Qx7VGBacMm9ZENQ7TnNObTYI4ShC+lHI16seduaxZo=
+go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.68.0/go.mod h1:Sje3i3MjSPKTSPvVWCaL8ugBzJwik3u4smCjUeuupqg=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.68.0 h1:CqXxU8VOmDefoh0+ztfGaymYbhdB/tT3zs79QaZTNGY=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.68.0/go.mod h1:BuhAPThV8PBHBvg8ZzZ/Ok3idOdhWIodywz2xEcRbJo=
 go.opentelemetry.io/otel v1.43.0 h1:mYIM03dnh5zfN7HautFE4ieIig9amkNANT+xcVxAj9I=
 go.opentelemetry.io/otel v1.43.0/go.mod h1:JuG+u74mvjvcm8vj8pI5XiHy1zDeoCS2LB1spIq7Ay0=
 go.opentelemetry.io/otel/metric v1.43.0 h1:d7638QeInOnuwOONPp4JAOGfbCEpYb+K6DVWvdxGzgM=
 go.opentelemetry.io/otel/metric v1.43.0/go.mod h1:RDnPtIxvqlgO8GRW18W6Z/4P462ldprJtfxHxyKd2PY=
-go.opentelemetry.io/otel/sdk v1.42.0 h1:LyC8+jqk6UJwdrI/8VydAq/hvkFKNHZVIWuslJXYsDo=
-go.opentelemetry.io/otel/sdk v1.42.0/go.mod h1:rGHCAxd9DAph0joO4W6OPwxjNTYWghRWmkHuGbayMts=
-go.opentelemetry.io/otel/sdk/metric v1.42.0 h1:D/1QR46Clz6ajyZ3G8SgNlTJKBdGp84q9RKCAZ3YGuA=
-go.opentelemetry.io/otel/sdk/metric v1.42.0/go.mod h1:Ua6AAlDKdZ7tdvaQKfSmnFTdHx37+J4ba8MwVCYM5hc=
+go.opentelemetry.io/otel/sdk v1.43.0 h1:pi5mE86i5rTeLXqoF/hhiBtUNcrAGHLKQdhg4h4V9Dg=
+go.opentelemetry.io/otel/sdk v1.43.0/go.mod h1:P+IkVU3iWukmiit/Yf9AWvpyRDlUeBaRg6Y+C58QHzg=
+go.opentelemetry.io/otel/sdk/metric v1.43.0 h1:S88dyqXjJkuBNLeMcVPRFXpRw2fuwdvfCGLEo89fDkw=
+go.opentelemetry.io/otel/sdk/metric v1.43.0/go.mod h1:C/RJtwSEJ5hzTiUz5pXF1kILHStzb9zFlIEe85bhj6A=
 go.opentelemetry.io/otel/trace v1.43.0 h1:BkNrHpup+4k4w+ZZ86CZoHHEkohws8AY+WTX09nk+3A=
 go.opentelemetry.io/otel/trace v1.43.0/go.mod h1:/QJhyVBUUswCphDVxq+8mld+AvhXZLhe+8WVFxiFff0=
 go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
@@ -298,9 +298,8 @@ golang.org/x/oauth2 v0.36.0 h1:peZ/1z27fi9hUOFCAZaHyrpWG5lwe0RJEEEeH0ThlIs=
 golang.org/x/oauth2 v0.36.0/go.mod h1:YDBUJMTkDnJS+A4BP4eZBjCqtokkg1hODuPjwiGPO7Q=
 golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
 golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
-golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/sys v0.43.0 h1:Rlag2XtaFTxp19wS8MXlJwTvoh8ArU6ezoyFsMyCTNI=
+golang.org/x/sys v0.43.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.41.0 h1:QCgPso/Q3RTJx2Th4bDLqML4W6iJiaXFq2/ftQF13YU=
 golang.org/x/term v0.41.0/go.mod h1:3pfBgksrReYfZ5lvYM0kSO0LIkAl4Yl2bXOkKP7Ec2A=
 golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
@@ -309,16 +308,16 @@ golang.org/x/time v0.15.0 h1:bbrp8t3bGUeFOx08pvsMYRTCVSMk89u4tKbNOZbp88U=
 golang.org/x/time v0.15.0/go.mod h1:Y4YMaQmXwGQZoFaVFk4YpCt4FLQMYKZe9oeV/f4MSno=
 gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
 gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
-google.golang.org/api v0.274.0 h1:aYhycS5QQCwxHLwfEHRRLf9yNsfvp1JadKKWBE54RFA=
-google.golang.org/api v0.274.0/go.mod h1:JbAt7mF+XVmWu6xNP8/+CTiGH30ofmCmk9nM8d8fHew=
+google.golang.org/api v0.275.0 h1:vfY5d9vFVJeWEZT65QDd9hbndr7FyZ2+6mIzGAh71NI=
+google.golang.org/api v0.275.0/go.mod h1:Fnag/EWUPIcJXuIkP1pjoTgS5vdxlk3eeemL7Do6bvw=
 google.golang.org/genai v1.52.1 h1:dYoljKtLDXMiBdVaClSJ/ZPwZ7j1N0lGjMhwOKOQUlk=
 google.golang.org/genai v1.52.1/go.mod h1:A3kkl0nyBjyFlNjgxIwKq70julKbIxpSxqKO5gw/gmk=
 google.golang.org/genproto v0.0.0-20260319201613-d00831a3d3e7 h1:XzmzkmB14QhVhgnawEVsOn6OFsnpyxNPRY9QV01dNB0=
 google.golang.org/genproto v0.0.0-20260319201613-d00831a3d3e7/go.mod h1:L43LFes82YgSonw6iTXTxXUX1OlULt4AQtkik4ULL/I=
 google.golang.org/genproto/googleapis/api v0.0.0-20260319201613-d00831a3d3e7 h1:41r6JMbpzBMen0R/4TZeeAmGXSJC7DftGINUodzTkPI=
 google.golang.org/genproto/googleapis/api v0.0.0-20260319201613-d00831a3d3e7/go.mod h1:EIQZ5bFCfRQDV4MhRle7+OgjNtZ6P1PiZBgAKuxXu/Y=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260401024825-9d38bb4040a9 h1:m8qni9SQFH0tJc1X0vmnpw/0t+AImlSvp30sEupozUg=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260401024825-9d38bb4040a9/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20260406210006-6f92a3bedf2d h1:wT2n40TBqFY6wiwazVK9/iTWbsQrgk5ZfCSVFLO9LQA=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20260406210006-6f92a3bedf2d/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
 google.golang.org/grpc v1.80.0 h1:Xr6m2WmWZLETvUNvIUmeD5OAagMw3FiKmMlTdViWsHM=
 google.golang.org/grpc v1.80.0/go.mod h1:ho/dLnxwi3EDJA4Zghp7k2Ec1+c2jqup0bFkw07bwF4=
 google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
@@ -23,18 +23,6 @@ import (
 // Version is injected at build time; fallback to "dev".
 var Version = "dev"

-// thinkingTagOpen and thinkingTagClose are the XML-style tags that some models
-// (Qwen, DeepSeek) wrap reasoning content in. We parse these to extract
-// reasoning/thinking content and send it as ACP thought updates.
-// Also support <think> format used by some models.
-const (
-	thinkingTagOpen    = "<thinking>"
-	thinkingTagClose   = "</thinking>"
-	shortThinkTagOpen  = "<think>"
-	shortThinkTagClose = "</think>"
-)
-
-// Agent implements the acp.Agent interface, delegating to Kit for LLM
 // execution, tool calls, and session management.
 type Agent struct {
 	conn     *acp.AgentSideConnection
@@ -42,10 +30,6 @@ type Agent struct {

 	// toolCallCounter provides unique IDs for tool calls within a turn.
 	toolCallCounter atomic.Int64
-
-	// inThinkingTag tracks whether we're currently inside a <thinking> tag
-	// when parsing streaming content from models that wrap reasoning in XML tags.
-	inThinkingTag bool
 }

 // NewAgent creates a new ACP agent backed by Kit.
@@ -144,9 +128,6 @@ func (a *Agent) Prompt(ctx context.Context, params acp.PromptRequest) (acp.Promp

 	log.Debug("acp: prompt", "session", sessionID, "prompt_len", len(promptText), "files", len(files))

-	// Reset thinking tag state for this new prompt turn
-	a.inThinkingTag = false
-
 	// Create a cancellable context for this prompt turn.
 	promptCtx, cancel := context.WithCancel(ctx)
 	sess.setCancel(cancel)
@@ -230,24 +211,8 @@ func (a *Agent) subscribeEvents(ctx context.Context, k *kit.Kit, sessionID acp.S
 		var update *acp.SessionUpdate
 		switch ev := e.(type) {
 		case kit.MessageUpdateEvent:
-			// Handle models that wrap reasoning in <thinking> tags (Qwen, DeepSeek)
-			// Parse the chunk and separate reasoning from regular text
-			reasoning, text := a.parseThinkingTags(ev.Chunk)
-
-			// Send reasoning update if we have reasoning content
-			if reasoning != "" {
-				u := acp.UpdateAgentThoughtText(reasoning)
-				_ = a.conn.SessionUpdate(ctx, acp.SessionNotification{
-					SessionId: sessionID,
-					Update:    u,
-				})
-			}
-
-			// Send text update if we have text content
-			if text != "" {
-				u := acp.UpdateAgentMessageText(text)
-				update = &u
-			}
+			u := acp.UpdateAgentMessageText(ev.Chunk)
+			update = &u

 		case kit.ReasoningDeltaEvent:
 			u := acp.UpdateAgentThoughtText(ev.Delta)
@@ -430,81 +395,6 @@ func extractPromptContent(blocks []acp.ContentBlock) (string, []kit.LLMFilePart)
 	return strings.Join(textParts, "\n"), files
 }

-// parseThinkingTags parses a text chunk for <thinking> or  tags and separates
-// reasoning content from regular text. This handles models (Qwen, DeepSeek)
-// that wrap reasoning in XML-style tags instead of using proper reasoning events.
-// Returns (reasoningContent, textContent).
-func (a *Agent) parseThinkingTags(chunk string) (reasoning string, text string) {
-	// Handle empty chunk
-	if chunk == "" {
-		return "", ""
-	}
-
-	// Determine which tag format to use (long or short)
-	openTag := thinkingTagOpen
-	closeTag := thinkingTagClose
-
-	if strings.Contains(chunk, shortThinkTagOpen) || strings.Contains(chunk, shortThinkTagClose) {
-		openTag = shortThinkTagOpen
-		closeTag = shortThinkTagClose
-	} else if !strings.Contains(chunk, thinkingTagOpen) && !strings.Contains(chunk, thinkingTagClose) && !a.inThinkingTag {
-		// No tags at all and not in thinking mode - return as text
-		return "", chunk
-	}
-
-	// Check for opening tag
-	if strings.Contains(chunk, openTag) {
-		parts := strings.SplitN(chunk, openTag, 2)
-
-		// Content before the opening tag is regular text
-		if !a.inThinkingTag && parts[0] != "" {
-			text = parts[0]
-		}
-
-		a.inThinkingTag = true
-
-		// Content after the opening tag is reasoning
-		if len(parts) > 1 {
-			// Check if the same chunk contains the closing tag
-			if strings.Contains(parts[1], closeTag) {
-				innerParts := strings.SplitN(parts[1], closeTag, 2)
-				reasoning = innerParts[0]
-				a.inThinkingTag = false
-
-				// Content after closing tag is regular text
-				if len(innerParts) > 1 && innerParts[1] != "" {
-					text += innerParts[1]
-				}
-			} else if parts[1] != "" {
-				// No closing tag yet, all remaining content is reasoning
-				reasoning = parts[1]
-			}
-		}
-		return reasoning, text
-	}
-
-	// Check for closing tag
-	if strings.Contains(chunk, closeTag) {
-		parts := strings.SplitN(chunk, closeTag, 2)
-		a.inThinkingTag = false
-
-		// Content before closing tag is reasoning
-		reasoning = parts[0]
-
-		// Content after closing tag is regular text
-		if len(parts) > 1 && parts[1] != "" {
-			text = parts[1]
-		}
-		return reasoning, text
-	}
-
-	// No tags found - content goes to current mode
-	if a.inThinkingTag {
-		return chunk, ""
-	}
-	return "", chunk
-}
-
 // isTextMimeType returns true if the MIME type indicates text content.
 func isTextMimeType(mimeType string) bool {
 	return strings.HasPrefix(mimeType, "text/") ||
@@ -35,6 +35,11 @@ type AgentConfig struct {
 	// CodingTools or tools with a custom WorkDir).
 	CoreTools []fantasy.AgentTool

+	// DisableCoreTools, when true, prevents loading any core tools.
+	// If both DisableCoreTools is true and CoreTools is empty, the agent
+	// will have no tools (useful for simple chat completions).
+	DisableCoreTools bool
+
 	// ToolWrapper is an optional function that wraps the combined tool list
 	// before it is passed to the LLM agent. Used by the extensions system
 	// to intercept tool calls/results.
@@ -84,6 +89,14 @@ type ReasoningCompleteHandler func()
 // Note: This is an alias for core.ToolOutputCallback to avoid import cycles.
 type ToolOutputHandler = core.ToolOutputCallback

+// StepMessagesHandler is a function type for persisting messages after each
+// complete step in a multi-step agent turn. The handler receives the messages
+// produced by the step (typically an assistant message with tool calls followed
+// by a tool-role message with results, or a final assistant message with text).
+// This enables incremental session persistence so that progress is saved as
+// it happens rather than only at the end of the turn.
+type StepMessagesHandler func(stepMessages []fantasy.Message)
+
 // StepUsageHandler is a function type for handling token usage after each
 // complete step in a multi-step agent turn. This enables real-time cost
 // tracking during long-running tool-calling conversations.
@@ -136,6 +149,11 @@ type GenerateWithLoopResult struct {
 	TotalUsage fantasy.Usage
 	// StopReason is the LLM provider's finish reason for the final response.
 	StopReason string
+	// PersistedMessageCount is the number of new messages (beyond the original
+	// input) that were already persisted incrementally via OnStepMessages during
+	// generation. The caller should skip these when doing post-generation
+	// persistence to avoid duplicates.
+	PersistedMessageCount int
 }

 // NewAgent creates a new Agent with core tools and optional MCP tool integration.
@@ -153,8 +171,16 @@ func NewAgent(ctx context.Context, agentConfig *AgentConfig) (*Agent, error) {

 	// Register core tools (direct AgentTool implementations, no MCP overhead).
 	// Use caller-provided tools if set, otherwise default to all core tools.
-	coreTools := agentConfig.CoreTools
-	if len(coreTools) == 0 {
+	// DisableCoreTools allows explicitly having zero tools (for chat-only mode).
+	var coreTools []fantasy.AgentTool
+	if agentConfig.DisableCoreTools && len(agentConfig.CoreTools) == 0 {
+		// Explicitly zero tools - chat-only mode
+		coreTools = nil
+	} else if len(agentConfig.CoreTools) > 0 {
+		// Custom tools provided - use them
+		coreTools = agentConfig.CoreTools
+	} else {
+		// Default: load all core tools
 		coreTools = core.AllTools()
 	}

@@ -364,7 +390,7 @@ func (a *Agent) GenerateWithLoop(ctx context.Context, messages []fantasy.Message
 	onResponse ResponseHandler, onToolCallContent ToolCallContentHandler,
 ) (*GenerateWithLoopResult, error) {
 	return a.GenerateWithLoopAndStreaming(ctx, messages, onToolCall, onToolExecution, onToolResult,
-		onResponse, onToolCallContent, nil, nil, nil, nil, nil)
+		onResponse, onToolCallContent, nil, nil, nil, nil, nil, nil)
 }

 // GenerateWithLoopAndStreaming processes messages using the agent with streaming and callbacks.
@@ -377,6 +403,7 @@ func (a *Agent) GenerateWithLoopAndStreaming(ctx context.Context, messages []fan
 	onReasoningDelta ReasoningDeltaHandler,
 	onReasoningComplete ReasoningCompleteHandler,
 	onToolOutput ToolOutputHandler,
+	onStepMessages StepMessagesHandler,
 	onStepUsage StepUsageHandler,
 ) (*GenerateWithLoopResult, error) {

@@ -416,6 +443,10 @@ func (a *Agent) GenerateWithLoopAndStreaming(ctx context.Context, messages []fan
 		// when it returns an error, but the OnStepFinish callback fires
 		// for every step that completed before the error occurred.
 		var completedStepMessages []fantasy.Message
+		// persistedCount tracks how many new messages (beyond the original
+		// input) were persisted incrementally via onStepMessages, so the
+		// caller can skip them during post-generation persistence.
+		var persistedCount int

 		// Use the streaming agent
 		streamCall := fantasy.AgentStreamCall{
@@ -501,6 +532,13 @@ func (a *Agent) GenerateWithLoopAndStreaming(ctx context.Context, messages []fan
 				// persisted even if a later step is cancelled.
 				completedStepMessages = append(completedStepMessages, step.Messages...)

+				// Persist step messages incrementally so progress is saved
+				// as it happens rather than only at the end of the turn.
+				if onStepMessages != nil && len(step.Messages) > 0 {
+					onStepMessages(step.Messages)
+					persistedCount += len(step.Messages)
+				}
+
 				if ctx.Err() != nil {
 					return ctx.Err()
 				}
@@ -579,7 +617,8 @@ func (a *Agent) GenerateWithLoopAndStreaming(ctx context.Context, messages []fan
 				partialMessages = append(partialMessages, messages...)
 				partialMessages = append(partialMessages, completedStepMessages...)
 				return &GenerateWithLoopResult{
-					ConversationMessages: partialMessages,
+					ConversationMessages:  partialMessages,
+					PersistedMessageCount: persistedCount,
 				}, err
 			}
 			return nil, err
@@ -594,7 +633,9 @@ func (a *Agent) GenerateWithLoopAndStreaming(ctx context.Context, messages []fan
 			onResponse(result.Response.Content.Text())
 		}

-		return convertAgentResult(result, messages), nil
+		r := convertAgentResult(result, messages)
+		r.PersistedMessageCount = persistedCount
+		return r, nil
 	}

 	// Non-streaming path with no callbacks — use the simpler Generate call.
@@ -41,6 +41,10 @@ type AgentCreationOptions struct {
 	// CoreTools overrides the default core tool set. If empty, core.AllTools()
 	// is used.
 	CoreTools []fantasy.AgentTool
+	// DisableCoreTools, when true, prevents loading any core tools.
+	// If both DisableCoreTools is true and CoreTools is empty, the agent
+	// will have no tools (useful for simple chat completions).
+	DisableCoreTools bool
 	// ToolWrapper wraps the combined tool list before agent creation.
 	ToolWrapper func([]fantasy.AgentTool) []fantasy.AgentTool
 	// ExtraTools are additional tools to include (e.g. from extensions).
@@ -63,6 +67,7 @@ func CreateAgent(ctx context.Context, opts *AgentCreationOptions) (*Agent, error
 		DebugLogger:       opts.DebugLogger,
 		AuthHandler:       opts.AuthHandler,
 		CoreTools:         opts.CoreTools,
+		DisableCoreTools:  opts.DisableCoreTools,
 		ToolWrapper:       opts.ToolWrapper,
 		ExtraTools:        opts.ExtraTools,
 		OnMCPServerLoaded: opts.OnMCPServerLoaded,
@@ -34,15 +34,10 @@ func LoadExtensions(extraPaths []string) ([]LoadedExtension, error) {
 	for _, p := range paths {
 		ext, err := loadSingleExtension(p)
 		if err != nil {
-			log.Warn("skipping extension", "path", p, "err", err)
 			continue
 		}
 		loaded = append(loaded, *ext)
-		log.Debug("loaded extension", "path", p,
-			"handlers", countHandlers(ext),
-			"tools", len(ext.Tools),
-			"commands", len(ext.Commands),
-			"tool_renderers", len(ext.ToolRenderers))
+		log.Debug("loaded extension", "path", p, "handlers", countHandlers(ext), "tools", len(ext.Tools), "commands", len(ext.Commands), "tool_renderers", len(ext.ToolRenderers))
 	}
 	return loaded, nil
 }
@@ -2,12 +2,12 @@ package extensions

 import (
 	"fmt"
+	"log"
 	"os"
 	"sort"
 	"strings"
 	"sync"

-	"github.com/charmbracelet/log"
 	"github.com/spf13/viper"
 )

@@ -370,10 +370,7 @@ func (r *Runner) Emit(event Event) (Result, error) {
 		for _, handler := range handlers {
 			result, err := safeCall(handler, event, ctx)
 			if err != nil {
-				log.Warn("extension handler error",
-					"path", ext.Path,
-					"event", event.Type(),
-					"err", err)
+				log.Printf("WARN extension handler error: path=%s event=%s err=%v", ext.Path, event.Type(), err)
 				continue
 			}
 			if result == nil {
@@ -707,9 +704,7 @@ func (r *Runner) EmitCustomEvent(name, data string) {
 	safeInvoke := func(h func(string)) {
 		defer func() {
 			if rec := recover(); rec != nil {
-				log.Warn("custom event handler panicked",
-					"event", name,
-					"err", fmt.Sprintf("%v", rec))
+				log.Printf("WARN custom event handler panicked: event=%s err=%v", name, rec)
 			}
 		}()
 		h(data)
@@ -3,13 +3,13 @@ package extensions
 import (
 	"context"
 	"fmt"
+	"log"
 	"os"
 	"path/filepath"
 	"strings"
 	"sync"
 	"time"

-	"github.com/charmbracelet/log"
 	"github.com/fsnotify/fsnotify"
 )

@@ -39,7 +39,7 @@ func NewWatcher(dirs []string, onReload func()) (*Watcher, error) {
 	for _, dir := range dirs {
 		// Watch the directory itself.
 		if err := fsw.Add(dir); err != nil {
-			log.Debug("watcher: skipping directory", "dir", dir, "err", err)
+			log.Printf("DEBUG watcher: skipping directory: dir=%s err=%v", dir, err)
 			continue
 		}

@@ -52,7 +52,7 @@ func NewWatcher(dirs []string, onReload func()) (*Watcher, error) {
 			if entry.IsDir() {
 				subdir := filepath.Join(dir, entry.Name())
 				if err := fsw.Add(subdir); err != nil {
-					log.Debug("watcher: skipping subdirectory", "dir", subdir, "err", err)
+					log.Printf("DEBUG watcher: skipping subdirectory: dir=%s err=%v", subdir, err)
 				}
 			}
 		}
@@ -101,7 +101,7 @@ func (w *Watcher) Start(ctx context.Context) {
 				continue
 			}

-			log.Debug("watcher: file changed", "file", event.Name, "op", event.Op)
+			log.Printf("DEBUG watcher: file changed: file=%s op=%s", event.Name, event.Op)

 			// Debounce: reset timer on each event.
 			if timer != nil {
@@ -113,14 +113,14 @@ func (w *Watcher) Start(ctx context.Context) {
 		case <-timerC:
 			timerC = nil
 			timer = nil
-			log.Debug("watcher: reloading extensions")
+			log.Printf("DEBUG watcher: reloading extensions")
 			w.onReload()

 		case err, ok := <-w.watcher.Errors:
 			if !ok {
 				return
 			}
-			log.Warn("watcher: error", "err", err)
+			log.Printf("WARN watcher: error: %v", err)
 		}
 	}
 }
@@ -33,6 +33,10 @@ type AgentSetupOptions struct {
 	// CoreTools overrides the default core tool set. If empty, core.AllTools()
 	// is used. Allows SDK users to pass custom tools (e.g. with WithWorkDir).
 	CoreTools []fantasy.AgentTool
+	// DisableCoreTools, when true, prevents loading any core tools.
+	// If both DisableCoreTools is true and CoreTools is empty, the agent
+	// will have no tools (useful for simple chat completions).
+	DisableCoreTools bool
 	// ExtraTools are additional tools added alongside core, MCP, and extension
 	// tools. They do not replace the defaults — they extend them.
 	ExtraTools []fantasy.AgentTool
@@ -197,6 +201,7 @@ func SetupAgent(ctx context.Context, opts AgentSetupOptions) (*AgentSetupResult,
 		DebugLogger:       debugLogger,
 		AuthHandler:       opts.AuthHandler,
 		CoreTools:         opts.CoreTools,
+		DisableCoreTools:  opts.DisableCoreTools,
 		ToolWrapper:       toolWrapper,
 		ExtraTools:        extraTools,
 		OnMCPServerLoaded: opts.OnMCPServerLoaded,
@@ -2,11 +2,10 @@ package prompts

 import (
 	"fmt"
+	"log"
 	"os"
 	"path/filepath"
 	"strings"
-
-	"github.com/charmbracelet/log"
 )

 // LoadOptions configures how templates are discovered and loaded.
@@ -74,10 +73,7 @@ func LoadAll(opts LoadOptions) ([]*PromptTemplate, []Diagnostic, error) {
 					DroppedPath: tpl.FilePath,
 					Reason:      fmt.Sprintf("template from %s overridden by %s", source, existing.Source),
 				})
-				log.Debug("template collision",
-					"name", tpl.Name,
-					"dropped", tpl.FilePath,
-					"kept", existing.FilePath)
+				log.Printf("DEBUG template collision: name=%s dropped=%s kept=%s", tpl.Name, tpl.FilePath, existing.FilePath)
 			} else {
 				tpl.Source = source
 				seen[tpl.Name] = tpl
@@ -0,0 +1,317 @@
+package session
+
+import (
+	"slices"
+	"testing"
+
+	"charm.land/fantasy"
+	"github.com/mark3labs/kit/internal/message"
+)
+
+// TestCompactionCreatesNewLeaf verifies that after compaction, the compaction
+// entry has no parent (creating a new root), and BuildContext returns only
+// the summary and kept messages, not the old compacted messages.
+func TestCompactionCreatesNewLeaf(t *testing.T) {
+	tm := InMemoryTreeSession("/test")
+
+	// Add some messages: M1, M2 (old, will be compacted), M3, M4 (kept)
+	msg1 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Message 1 - old"}}}
+	msg2 := message.Message{Role: message.RoleAssistant, Parts: []message.ContentPart{message.TextContent{Text: "Message 2 - old"}}}
+	msg3 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Message 3 - kept"}}}
+	msg4 := message.Message{Role: message.RoleAssistant, Parts: []message.ContentPart{message.TextContent{Text: "Message 4 - kept"}}}
+
+	_, _ = tm.AppendMessage(msg1)
+	_, _ = tm.AppendMessage(msg2)
+	id3, _ := tm.AppendMessage(msg3)
+	id4, _ := tm.AppendMessage(msg4)
+
+	// Verify initial state - all messages should be in context
+	messages, _, _ := tm.BuildContext()
+	if len(messages) != 4 {
+		t.Fatalf("expected 4 messages before compaction, got %d", len(messages))
+	}
+
+	// Verify entry IDs
+	entryIDs := tm.GetContextEntryIDs()
+	if len(entryIDs) != 4 {
+		t.Fatalf("expected 4 entry IDs before compaction, got %d", len(entryIDs))
+	}
+
+	// Now add a compaction entry, simulating that M3 is the first kept entry
+	summary := "Summary of old messages"
+	compactionID, err := tm.AppendCompaction(summary, id3, 1000, 500, 2, []string{}, []string{})
+	if err != nil {
+		t.Fatalf("failed to append compaction: %v", err)
+	}
+
+	// Verify the compaction entry has no parent (empty ParentID)
+	compactionEntry := tm.GetEntry(compactionID).(*CompactionEntry)
+	if compactionEntry.ParentID != "" {
+		t.Errorf("compaction entry should have no parent, got %q", compactionEntry.ParentID)
+	}
+
+	// Verify the leaf is now the compaction entry
+	if tm.GetLeafID() != compactionID {
+		t.Errorf("leaf should be compaction entry %q, got %q", compactionID, tm.GetLeafID())
+	}
+
+	// Now BuildContext should return: [summary] + [M3, M4]
+	messages, _, _ = tm.BuildContext()
+	if len(messages) != 3 {
+		t.Fatalf("expected 3 messages after compaction (summary + 2 kept), got %d", len(messages))
+	}
+
+	// First message should be the summary
+	if messages[0].Role != fantasy.MessageRoleSystem {
+		t.Errorf("first message should be system summary, got %s", messages[0].Role)
+	}
+	summaryText := messages[0].Content[0].(fantasy.TextPart).Text
+	if summaryText != "[Conversation summary — earlier messages were compacted]\n\n"+summary {
+		t.Errorf("unexpected summary text: %s", summaryText)
+	}
+
+	// Second message should be M3 (kept)
+	if messages[1].Role != fantasy.MessageRoleUser {
+		t.Errorf("second message should be user (M3), got %s", messages[1].Role)
+	}
+	m3Text := messages[1].Content[0].(fantasy.TextPart).Text
+	if m3Text != "Message 3 - kept" {
+		t.Errorf("unexpected M3 text: %s", m3Text)
+	}
+
+	// Third message should be M4 (kept)
+	if messages[2].Role != fantasy.MessageRoleAssistant {
+		t.Errorf("third message should be assistant (M4), got %s", messages[2].Role)
+	}
+	m4Text := messages[2].Content[0].(fantasy.TextPart).Text
+	if m4Text != "Message 4 - kept" {
+		t.Errorf("unexpected M4 text: %s", m4Text)
+	}
+
+	// Verify GetContextEntryIDs returns correct IDs
+	entryIDs = tm.GetContextEntryIDs()
+	if len(entryIDs) != 3 {
+		t.Fatalf("expected 3 entry IDs after compaction (empty for summary + 2 kept), got %d: %v", len(entryIDs), entryIDs)
+	}
+
+	// First entry ID should be empty (summary has no entry)
+	if entryIDs[0] != "" {
+		t.Errorf("first entry ID should be empty (summary), got %q", entryIDs[0])
+	}
+
+	// Second and third should be id3 and id4 (the kept messages)
+	if entryIDs[1] != id3 {
+		t.Errorf("second entry ID should be %q (M3), got %q", id3, entryIDs[1])
+	}
+	if entryIDs[2] != id4 {
+		t.Errorf("third entry ID should be %q (M4), got %q", id4, entryIDs[2])
+	}
+}
+
+// TestCompactionWithNewMessagesAfterCompaction verifies that messages appended
+// after compaction are correctly included in the context.
+func TestCompactionWithNewMessagesAfterCompaction(t *testing.T) {
+	tm := InMemoryTreeSession("/test")
+
+	// Add initial messages
+	msg1 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Message 1"}}}
+	msg2 := message.Message{Role: message.RoleAssistant, Parts: []message.ContentPart{message.TextContent{Text: "Message 2"}}}
+	msg3 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Message 3 - kept"}}}
+
+	_, _ = tm.AppendMessage(msg1)
+	_, _ = tm.AppendMessage(msg2)
+	id3, _ := tm.AppendMessage(msg3)
+
+	// Compact, keeping only M3
+	_, _ = tm.AppendCompaction("Summary", id3, 1000, 500, 2, []string{}, []string{})
+
+	// Add a new message after compaction
+	msg4 := message.Message{Role: message.RoleAssistant, Parts: []message.ContentPart{message.TextContent{Text: "Message 4 - after compaction"}}}
+	_, _ = tm.AppendMessage(msg4)
+
+	// BuildContext should return: [summary] + [M4 (new after compaction)] + [M3 (kept)]
+	messages, _, _ := tm.BuildContext()
+	if len(messages) != 3 {
+		t.Fatalf("expected 3 messages (summary + M4 + M3), got %d: %+v", len(messages), messages)
+	}
+
+	// Verify order: summary, M4 (new), M3 (kept)
+	if messages[0].Role != fantasy.MessageRoleSystem {
+		t.Errorf("first message should be summary, got %s", messages[0].Role)
+	}
+	if messages[1].Role != fantasy.MessageRoleAssistant {
+		t.Errorf("second message should be assistant (M4), got %s", messages[1].Role)
+	}
+	m4Text := messages[1].Content[0].(fantasy.TextPart).Text
+	if m4Text != "Message 4 - after compaction" {
+		t.Errorf("unexpected M4 text: %s", m4Text)
+	}
+	if messages[2].Role != fantasy.MessageRoleUser {
+		t.Errorf("third message should be user (M3), got %s", messages[2].Role)
+	}
+
+	// Verify that M1 is NOT in the context
+	for i, msg := range messages {
+		if msg.Role == fantasy.MessageRoleUser {
+			text := msg.Content[0].(fantasy.TextPart).Text
+			if text == "Message 1" {
+				t.Errorf("Message 1 (compacted) should not be in context at index %d", i)
+			}
+		}
+	}
+}
+
+// TestCompactionWithNoKeptMessages verifies compaction when all messages are compacted.
+func TestCompactionWithNoKeptMessages(t *testing.T) {
+	tm := InMemoryTreeSession("/test")
+
+	// Add messages that will all be compacted
+	msg1 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Message 1"}}}
+	msg2 := message.Message{Role: message.RoleAssistant, Parts: []message.ContentPart{message.TextContent{Text: "Message 2"}}}
+
+	if _, err := tm.AppendMessage(msg1); err != nil {
+		t.Fatalf("failed to append message: %v", err)
+	}
+	if _, err := tm.AppendMessage(msg2); err != nil {
+		t.Fatalf("failed to append message: %v", err)
+	}
+
+	// Compact with no kept messages (empty firstKeptEntryID)
+	summary := "All messages summarized"
+	compactionID, _ := tm.AppendCompaction(summary, "", 1000, 100, 2, []string{}, []string{})
+
+	// Verify the compaction entry has no parent
+	compactionEntry := tm.GetEntry(compactionID).(*CompactionEntry)
+	if compactionEntry.ParentID != "" {
+		t.Errorf("compaction entry should have no parent, got %q", compactionEntry.ParentID)
+	}
+
+	// BuildContext should return only the summary
+	messages, _, _ := tm.BuildContext()
+	if len(messages) != 1 {
+		t.Fatalf("expected 1 message (summary only), got %d: %+v", len(messages), messages)
+	}
+	if messages[0].Role != fantasy.MessageRoleSystem {
+		t.Errorf("message should be system summary, got %s", messages[0].Role)
+	}
+}
+
+// TestMultipleCompactions verifies that multiple compactions work correctly.
+func TestMultipleCompactions(t *testing.T) {
+	tm := InMemoryTreeSession("/test")
+
+	// First batch of messages
+	msg1 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Batch 1 - User"}}}
+	msg2 := message.Message{Role: message.RoleAssistant, Parts: []message.ContentPart{message.TextContent{Text: "Batch 1 - Assistant"}}}
+	id1, _ := tm.AppendMessage(msg1)
+	id2, _ := tm.AppendMessage(msg2)
+
+	// First compaction
+	_, _ = tm.AppendCompaction("Summary 1", id1, 1000, 500, 1, []string{}, []string{})
+
+	// Second batch
+	msg3 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Batch 2 - User"}}}
+	msg4 := message.Message{Role: message.RoleAssistant, Parts: []message.ContentPart{message.TextContent{Text: "Batch 2 - Assistant"}}}
+	id3, _ := tm.AppendMessage(msg3)
+	id4, _ := tm.AppendMessage(msg4)
+
+	// Second compaction (compacting the first compaction + batch 2)
+	// Note: id3 is the first kept entry, so id3 and id4 should be preserved
+	compactionID2, _ := tm.AppendCompaction("Summary 2", id3, 1000, 500, 3, []string{}, []string{})
+
+	// Verify second compaction has no parent
+	compactionEntry2 := tm.GetEntry(compactionID2).(*CompactionEntry)
+	if compactionEntry2.ParentID != "" {
+		t.Errorf("second compaction entry should have no parent, got %q", compactionEntry2.ParentID)
+	}
+
+	// Add final message
+	msg5 := message.Message{Role: message.RoleUser, Parts: []message.ContentPart{message.TextContent{Text: "Final message"}}}
+	id5, _ := tm.AppendMessage(msg5)
+
+	// BuildContext should include:
+	// - Summary 2 (from second compaction)
+	// - msg5 (final message)
+	// - msg3, msg4 (kept from second compaction)
+	// But NOT Summary 1 or msg1, msg2 (they're before the first kept entry of compaction 2)
+	messages, _, _ := tm.BuildContext()
+
+	// Should have: Summary 2 + msg5 + msg3 + msg4 = 4 messages
+	if len(messages) != 4 {
+		t.Fatalf("expected 4 messages (Summary 2 + msg5 + msg3 + msg4), got %d: %+v", len(messages), messages)
+	}
+
+	// First should be Summary 2
+	if messages[0].Role != fantasy.MessageRoleSystem {
+		t.Errorf("first message should be system (Summary 2), got %s", messages[0].Role)
+	}
+	summaryText := messages[0].Content[0].(fantasy.TextPart).Text
+	if summaryText != "[Conversation summary — earlier messages were compacted]\n\nSummary 2" {
+		t.Errorf("unexpected summary: %s", summaryText)
+	}
+
+	// Verify msg5 is included
+	foundFinal := false
+	for _, msg := range messages {
+		if msg.Role == fantasy.MessageRoleUser {
+			text := msg.Content[0].(fantasy.TextPart).Text
+			if text == "Final message" {
+				foundFinal = true
+				break
+			}
+		}
+	}
+	if !foundFinal {
+		t.Error("Final message (msg5) should be in context")
+	}
+
+	// Verify msg1, msg2 are NOT included (compacted by first compaction, then second)
+	for _, msg := range messages {
+		if msg.Role == fantasy.MessageRoleUser || msg.Role == fantasy.MessageRoleAssistant {
+			text := msg.Content[0].(fantasy.TextPart).Text
+			if text == "Batch 1 - User" || text == "Batch 1 - Assistant" {
+				t.Errorf("Batch 1 messages should not be in context, found: %s", text)
+			}
+		}
+	}
+
+	// Verify entry IDs
+	entryIDs := tm.GetContextEntryIDs()
+	if len(entryIDs) != 4 {
+		t.Fatalf("expected 4 entry IDs, got %d: %v", len(entryIDs), entryIDs)
+	}
+
+	// First should be empty (summary)
+	if entryIDs[0] != "" {
+		t.Errorf("first entry ID should be empty (summary), got %q", entryIDs[0])
+	}
+
+	// Check that id5 is in the list
+	if !slices.Contains(entryIDs, id5) {
+		t.Errorf("id5 (final message) should be in entry IDs, got %v", entryIDs)
+	}
+
+	// Verify id3 and id4 ARE in the list (they were kept)
+	foundID3, foundID4 := false, false
+	for _, id := range entryIDs {
+		if id == id3 {
+			foundID3 = true
+		}
+		if id == id4 {
+			foundID4 = true
+		}
+	}
+	if !foundID3 {
+		t.Errorf("id3 (kept message) should be in entry IDs, got %v", entryIDs)
+	}
+	if !foundID4 {
+		t.Errorf("id4 (kept message) should be in entry IDs, got %v", entryIDs)
+	}
+
+	// Verify id1 and id2 are NOT in the list (they were compacted away)
+	for _, id := range entryIDs {
+		if id == id1 || id == id2 {
+			t.Errorf("id1 or id2 (compacted) should not be in entry IDs, found %q in %v", id, entryIDs)
+		}
+	}
+}
@@ -509,11 +509,19 @@ func (tm *TreeManager) AppendExtensionData(extType, data string) (string, error)
 // AppendCompaction adds a compaction entry to the tree. The entry records
 // the summary and the ID of the first entry that should be preserved in the
 // LLM context. Messages before that entry are replaced by the summary.
+//
+// The compaction entry becomes a new "root" for the post-compaction branch
+// with no parent (empty ParentID). This breaks the parent chain so that old
+// compacted messages are no longer traversed when building context. The kept
+// messages are explicitly collected via FirstKeptEntryID in BuildContext.
 func (tm *TreeManager) AppendCompaction(summary, firstKeptEntryID string, tokensBefore, tokensAfter, messagesRemoved int, readFiles, modifiedFiles []string) (string, error) {
 	tm.mu.Lock()
 	defer tm.mu.Unlock()

-	entry := NewCompactionEntry(tm.leafID, summary, firstKeptEntryID, tokensBefore, tokensAfter, messagesRemoved, readFiles, modifiedFiles)
+	// The compaction entry has no parent, making it a new "root" for the
+	// post-compaction branch. This ensures old compacted messages are not
+	// traversed when walking from the current leaf.
+	entry := NewCompactionEntry("", summary, firstKeptEntryID, tokensBefore, tokensAfter, messagesRemoved, readFiles, modifiedFiles)
 	if err := tm.appendAndPersist(entry); err != nil {
 		return "", err
 	}
@@ -683,14 +691,18 @@ func (tm *TreeManager) BuildContext() (messages []fantasy.Message, provider stri
 	// Find the last compaction entry on this branch — it determines
 	// which older messages are replaced by the summary.
 	var lastCompaction *CompactionEntry
+	var compactionIndex = -1
 	for i := len(branch) - 1; i >= 0; i-- {
 		if c, ok := branch[i].(*CompactionEntry); ok {
 			lastCompaction = c
+			compactionIndex = i
 			break
 		}
 	}

-	// If there is a compaction, inject the summary first.
+	// If there is a compaction, inject the summary first and collect
+	// the kept messages starting from FirstKeptEntryID (since the
+	// compaction entry's parent chain doesn't include them).
 	if lastCompaction != nil {
 		messages = append(messages, fantasy.Message{
 			Role: fantasy.MessageRoleSystem,
@@ -700,21 +712,104 @@ func (tm *TreeManager) BuildContext() (messages []fantasy.Message, provider stri
 				},
 			},
 		})
-	}

-	// Determine whether to skip entries (everything before firstKeptEntryID).
-	skipping := lastCompaction != nil
-	for _, entry := range branch {
-		// Once we reach the first kept entry, stop skipping.
-		if skipping {
-			entryID := tm.EntryID(entry)
-			if entryID == lastCompaction.FirstKeptEntryID {
-				skipping = false
-			} else {
+		// Collect entries from the compaction entry itself (at compactionIndex)
+		// and any entries before it in the branch (newer messages).
+		for i := compactionIndex; i < len(branch); i++ {
+			entry := branch[i]
+			switch e := entry.(type) {
+			case *MessageEntry:
+				msg, err := e.ToMessage()
+				if err != nil {
+					continue // skip malformed entries
+				}
+				msgs := msg.ToLLMMessages()
+				messages = append(messages, msgs...)
+
+			case *BranchSummaryEntry:
+				// Convert branch summary to a user message for context.
+				if e.Summary != "" {
+					messages = append(messages, fantasy.Message{
+						Role: fantasy.MessageRoleUser,
+						Content: []fantasy.MessagePart{
+							fantasy.TextPart{
+								Text: fmt.Sprintf("[Branch context: %s]", e.Summary),
+							},
+						},
+					})
+				}
+
+			case *ModelChangeEntry:
+				provider = e.Provider
+				modelID = e.ModelID
+
+			case *CompactionEntry:
+				// Already handled above (summary injected).
 				continue
 			}
 		}

+		// Now collect the kept messages starting from FirstKeptEntryID.
+		// These are not in the current branch because the compaction entry
+		// is parented to the first kept entry's parent, not the first kept entry.
+		// We iterate through entries in order (not using getBranchLocked) to avoid
+		// walking back to old compacted messages.
+		// We stop when we reach the compaction entry to avoid double-counting
+		// messages that were added after the compaction.
+		if lastCompaction.FirstKeptEntryID != "" {
+			found := false
+			for _, entry := range tm.entries {
+				entryID := tm.EntryID(entry)
+
+				// Skip entries until we reach the first kept entry.
+				if !found {
+					if entryID == lastCompaction.FirstKeptEntryID {
+						found = true
+					} else {
+						continue
+					}
+				}
+
+				// Stop when we reach the compaction entry itself.
+				// Messages after the compaction are collected from the branch walk above.
+				if entryID == lastCompaction.ID {
+					break
+				}
+
+				// Process this kept entry.
+				switch e := entry.(type) {
+				case *MessageEntry:
+					msg, err := e.ToMessage()
+					if err != nil {
+						continue
+					}
+					msgs := msg.ToLLMMessages()
+					messages = append(messages, msgs...)
+
+				case *BranchSummaryEntry:
+					if e.Summary != "" {
+						messages = append(messages, fantasy.Message{
+							Role: fantasy.MessageRoleUser,
+							Content: []fantasy.MessagePart{
+								fantasy.TextPart{
+									Text: fmt.Sprintf("[Branch context: %s]", e.Summary),
+								},
+							},
+						})
+					}
+
+				case *ModelChangeEntry:
+					provider = e.Provider
+					modelID = e.ModelID
+				}
+			}
+		}
+
+		return messages, provider, modelID
+	}
+
+	// No compaction - process the entire branch normally.
+	for _, entry := range branch {
 		switch e := entry.(type) {
 		case *MessageEntry:
 			msg, err := e.ToMessage()
@@ -740,10 +835,6 @@ func (tm *TreeManager) BuildContext() (messages []fantasy.Message, provider stri
 		case *ModelChangeEntry:
 			provider = e.Provider
 			modelID = e.ModelID
-
-		case *CompactionEntry:
-			// Already handled above (the last one on the branch).
-			continue
 		}
 	}

@@ -853,31 +944,92 @@ func (tm *TreeManager) GetContextEntryIDs() []string {

 	// Find the last compaction entry for skip logic.
 	var lastCompaction *CompactionEntry
+	var compactionIndex = -1
 	for i := len(branch) - 1; i >= 0; i-- {
 		if c, ok := branch[i].(*CompactionEntry); ok {
 			lastCompaction = c
+			compactionIndex = i
 			break
 		}
 	}

 	var ids []string

-	// If there's a compaction summary injected, it has no entry ID.
+	// If there's a compaction, we need to collect IDs from:
+	// 1. Entries after the compaction entry in the branch (newer messages)
+	// 2. Entries from FirstKeptEntryID onwards (kept messages)
 	if lastCompaction != nil {
-		ids = append(ids, "") // placeholder for the summary system message
-	}
+		// Placeholder for the summary system message (no entry ID).
+		ids = append(ids, "")

-	skipping := lastCompaction != nil
-	for _, entry := range branch {
-		if skipping {
-			entryID := tm.EntryID(entry)
-			if entryID == lastCompaction.FirstKeptEntryID {
-				skipping = false
-			} else {
-				continue
+		// Collect IDs from entries after the compaction entry (newer messages).
+		for i := compactionIndex + 1; i < len(branch); i++ {
+			entry := branch[i]
+			switch e := entry.(type) {
+			case *MessageEntry:
+				msg, err := e.ToMessage()
+				if err != nil {
+					continue
+				}
+				msgs := msg.ToLLMMessages()
+				for range msgs {
+					ids = append(ids, e.ID)
+				}
+
+			case *BranchSummaryEntry:
+				if e.Summary != "" {
+					ids = append(ids, e.ID)
+				}
 			}
 		}

+		// Collect IDs from the kept messages starting at FirstKeptEntryID.
+		// We iterate through entries in order (not using getBranchLocked) to avoid
+		// walking back to old compacted messages.
+		// We stop when we reach the compaction entry to avoid double-counting.
+		if lastCompaction.FirstKeptEntryID != "" {
+			found := false
+			for _, entry := range tm.entries {
+				entryID := tm.EntryID(entry)
+
+				// Skip entries until we reach the first kept entry.
+				if !found {
+					if entryID == lastCompaction.FirstKeptEntryID {
+						found = true
+					} else {
+						continue
+					}
+				}
+
+				// Stop when we reach the compaction entry itself.
+				if entryID == lastCompaction.ID {
+					break
+				}
+
+				switch e := entry.(type) {
+				case *MessageEntry:
+					msg, err := e.ToMessage()
+					if err != nil {
+						continue
+					}
+					msgs := msg.ToLLMMessages()
+					for range msgs {
+						ids = append(ids, e.ID)
+					}
+
+				case *BranchSummaryEntry:
+					if e.Summary != "" {
+						ids = append(ids, e.ID)
+					}
+				}
+			}
+		}
+
+		return ids
+	}
+
+	// No compaction - collect IDs from the entire branch.
+	for _, entry := range branch {
 		switch e := entry.(type) {
 		case *MessageEntry:
 			msg, err := e.ToMessage()
@@ -893,9 +1045,6 @@ func (tm *TreeManager) GetContextEntryIDs() []string {
 			if e.Summary != "" {
 				ids = append(ids, e.ID)
 			}
-
-		case *CompactionEntry:
-			continue
 		}
 	}

@@ -5,7 +5,6 @@ import (
 	"os"
 	"time"

-	"charm.land/fantasy"
 	"charm.land/lipgloss/v2"
 	"golang.org/x/term"

@@ -173,33 +172,6 @@ func (c *CLI) DisplayDebugConfig(config map[string]any) {
 	fmt.Println(c.renderer.RenderDebugConfigMessage(config, time.Now()).Content)
 }

-// UpdateUsageFromResponse records token usage using metadata from the fantasy
-// response. Only actual API-reported tokens are used for cost tracking.
-// If the provider doesn't report token counts, no usage is recorded.
-func (c *CLI) UpdateUsageFromResponse(response *fantasy.Response, inputText string) {
-	if c.usageTracker == nil {
-		return
-	}
-
-	usage := response.Usage
-	inputTokens := int(usage.InputTokens)
-	outputTokens := int(usage.OutputTokens)
-
-	// Only use actual API-reported tokens for cost tracking.
-	// We intentionally do NOT estimate tokens - estimation is inaccurate
-	// and should never be used for cost calculations.
-	if inputTokens > 0 {
-		cacheReadTokens := int(usage.CacheReadTokens)
-		cacheWriteTokens := int(usage.CacheCreationTokens)
-		c.usageTracker.UpdateUsage(inputTokens, outputTokens, cacheReadTokens, cacheWriteTokens)
-		// Per-response usage is a single API call, so it represents the
-		// actual context window fill level.
-		c.usageTracker.SetContextTokens(inputTokens + outputTokens)
-	}
-	// If inputTokens is 0, the provider didn't report usage - we skip recording
-	// rather than estimating, to ensure cost accuracy.
-}
-
 // DisplayUsageAfterResponse renders and displays token usage information immediately
 // following an AI response. This provides real-time feedback about the cost and
 // token consumption of each interaction.
@@ -69,7 +69,7 @@ type InputComponent struct {
 	hideHint bool

 	// agentBusy indicates the agent is currently working. When true, the
-	// hint text shows steering shortcut (Ctrl+S) instead of submit.
+	// hint text shows steering shortcut (Ctrl+X s) instead of submit.
 	agentBusy bool

 	// pendingImages holds clipboard images attached to the next submission.
@@ -109,7 +109,7 @@ func NewInputComponent(width int, title string, appCtrl AppController) *InputCom
 	ta.Placeholder = "Type your message..."
 	ta.ShowLineNumbers = false
 	ta.Prompt = ""
-	ta.CharLimit = 5000
+	ta.CharLimit = 0
 	ta.SetWidth(width - 8) // Account for container padding, border and internal padding
 	ta.SetHeight(3)        // Default to 3 lines like huh
 	ta.Focus()
@@ -514,12 +514,12 @@ func (s *InputComponent) View() tea.View {
 		availableHintWidth := s.width - 3
 		if s.agentBusy {
 			// When the agent is working, show steering shortcut.
-			if availableHintWidth >= 55 {
-				hint = "enter queue • ctrl+s steer • esc esc cancel"
-			} else if availableHintWidth >= 35 {
-				hint = "↵ queue • ^S steer • esc×2 cancel"
+			if availableHintWidth >= 60 {
+				hint = "enter queue • ctrl+x s steer • esc esc cancel"
+			} else if availableHintWidth >= 40 {
+				hint = "↵ queue • ^X s steer • esc×2 cancel"
 			} else {
-				hint = "^S steer"
+				hint = "^X s steer"
 			}
 		} else if availableHintWidth >= 67 {
 			hint = "enter submit • ctrl+j / shift+enter new line • ctrl+v paste image"
@@ -152,7 +152,7 @@ func (r *MessageRenderer) SetWidth(width int) {

 // RenderUserMessage renders a user's input message using herald Tip alert
 func (r *MessageRenderer) RenderUserMessage(content string, timestamp time.Time) UIMessage {
-	rendered := render.UserBlock(content, r.ty, style.GetTheme())
+	rendered := render.UserBlock(content, r.width, r.ty, style.GetTheme())

 	return UIMessage{
 		Type:      UserMessage,
@@ -477,7 +477,7 @@ type AppModel struct {
 	queuedMessages []string

 	// steeringMessages stores the text of prompts that were sent as steer
-	// messages (injected mid-turn via Ctrl+S). Rendered with a "STEERING"
+	// messages (injected mid-turn via Ctrl+X s). Rendered with a "STEERING"
 	// badge above the input. Cleared when the steer is consumed.
 	steeringMessages []string

@@ -498,6 +498,11 @@ type AppModel struct {
 	// A second ESC within 2 seconds will cancel the current step.
 	canceling bool

+	// leaderKeyActive tracks whether the Ctrl+X leader key prefix has been
+	// pressed. The next keypress is interpreted as a chord suffix (e.g. "s"
+	// for steer). Cleared on any subsequent keypress.
+	leaderKeyActive bool
+
 	// providerName is the LLM provider for the startup message.
 	providerName string

@@ -1268,6 +1273,71 @@ func (m *AppModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			return m, tea.Batch(cmds...)
 		}

+		// ── Leader key chord handling (Ctrl+X prefix) ──────────────
+		// If the leader key was previously pressed, the current key
+		// completes the chord. We consume it regardless of match so
+		// the prefix doesn't leak to child components.
+		if m.leaderKeyActive {
+			m.leaderKeyActive = false
+			switch msg.String() {
+			case "s":
+				// Ctrl+X s → Steer: inject the current input as a steering
+				// message into the running agent turn.
+				if m.state == stateWorking && m.appCtrl != nil {
+					var text string
+					if ic, ok := m.input.(*InputComponent); ok {
+						text = strings.TrimSpace(ic.textarea.Value())
+					}
+					if text != "" {
+						// Clear the input, collect pending images, and push to history.
+						var images []uicore.ImageAttachment
+						if ic, ok := m.input.(*InputComponent); ok {
+							ic.pushHistory(text)
+							ic.textarea.SetValue("")
+							images = ic.ClearPendingImages()
+						}
+
+						// Preprocess @file references.
+						processedText := text
+						if m.cwd != "" {
+							processedText = fileutil.ProcessFileAttachments(text, m.cwd)
+						}
+
+						// Convert image attachments to kit.LLMFilePart for the app layer.
+						var fileParts []kit.LLMFilePart
+						for _, img := range images {
+							fileParts = append(fileParts, kit.LLMFilePart{
+								Data:      img.Data,
+								MediaType: img.MediaType,
+							})
+						}
+
+						// Build display text (include image count if any).
+						displayText := text
+						if len(images) > 0 {
+							displayText = fmt.Sprintf("%s\n[%d image(s) attached]", text, len(images))
+						}
+
+						// Inject the steer message.
+						sLen := m.appCtrl.SteerWithFiles(processedText, fileParts)
+						if sLen > 0 {
+							m.steeringMessages = append(m.steeringMessages, displayText)
+							m.layoutDirty = true
+						} else {
+							// Started immediately (agent was idle).
+							m.pendingUserPrints = append(m.pendingUserPrints, displayText)
+							m.flushStreamAndPendingUserMessages()
+							if m.state != stateWorking {
+								m.state = stateWorking
+							}
+						}
+					}
+				}
+			}
+			// Chord consumed — don't propagate to children.
+			return m, tea.Batch(cmds...)
+		}
+
 		switch msg.String() {
 		case "esc":
 			if m.state == stateWorking {
@@ -1286,61 +1356,10 @@ func (m *AppModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			}
 			// In other states pass ESC through to children below.

-		case "ctrl+s":
-			// Steer: inject the current input as a steering message into the
-			// running agent turn. Only active during stateWorking — in input
-			// state, Ctrl+S is passed through to children (no-op by default).
-			if m.state == stateWorking && m.appCtrl != nil {
-				var text string
-				if ic, ok := m.input.(*InputComponent); ok {
-					text = strings.TrimSpace(ic.textarea.Value())
-				}
-				if text != "" {
-					// Clear the input, collect pending images, and push to history.
-					var images []uicore.ImageAttachment
-					if ic, ok := m.input.(*InputComponent); ok {
-						ic.pushHistory(text)
-						ic.textarea.SetValue("")
-						images = ic.ClearPendingImages()
-					}
-
-					// Preprocess @file references.
-					processedText := text
-					if m.cwd != "" {
-						processedText = fileutil.ProcessFileAttachments(text, m.cwd)
-					}
-
-					// Convert image attachments to kit.LLMFilePart for the app layer.
-					var fileParts []kit.LLMFilePart
-					for _, img := range images {
-						fileParts = append(fileParts, kit.LLMFilePart{
-							Data:      img.Data,
-							MediaType: img.MediaType,
-						})
-					}
-
-					// Build display text (include image count if any).
-					displayText := text
-					if len(images) > 0 {
-						displayText = fmt.Sprintf("%s\n[%d image(s) attached]", text, len(images))
-					}
-
-					// Inject the steer message.
-					sLen := m.appCtrl.SteerWithFiles(processedText, fileParts)
-					if sLen > 0 {
-						m.steeringMessages = append(m.steeringMessages, displayText)
-						m.layoutDirty = true
-					} else {
-						// Started immediately (agent was idle).
-						m.pendingUserPrints = append(m.pendingUserPrints, displayText)
-						m.flushStreamAndPendingUserMessages()
-						if m.state != stateWorking {
-							m.state = stateWorking
-						}
-					}
-				}
-				return m, tea.Batch(cmds...)
-			}
+		case "ctrl+x":
+			// Activate leader key prefix — the next keypress completes the chord.
+			m.leaderKeyActive = true
+			return m, tea.Batch(cmds...)
 		}

 		// Route key events to the focused child. Check for editor
@@ -2462,22 +2481,34 @@ func (m *AppModel) renderHeaderFooter(getter func() *WidgetData) string {
 	return renderContentBlock(data.Text, m.width, opts...)
 }

+// maxQueuedMessageLines is the maximum number of visible content lines
+// rendered for each queued or steering message block. Messages exceeding
+// this limit are truncated with an ellipsis to prevent large pastes from
+// overflowing the screen and squeezing the stream region to zero.
+const maxQueuedMessageLines = 3
+
 // renderQueuedMessages renders queued and steering prompts as styled content
 // blocks with badges, anchored between the separator and input. Steering
 // messages use a distinct "STEERING" badge to differentiate from queued ones.
+// Long messages are visually truncated to maxQueuedMessageLines.
 func (m *AppModel) renderQueuedMessages() string {
 	if len(m.queuedMessages) == 0 && len(m.steeringMessages) == 0 {
 		return ""
 	}
 	theme := style.GetTheme()

+	// Available content width inside the block: container minus border (1)
+	// minus left padding (2). Used to estimate line wrapping for truncation.
+	contentWidth := max(m.width-3, 10)
+
 	var blocks []string

 	// Render steering messages first (higher priority).
 	if len(m.steeringMessages) > 0 {
 		badge := style.CreateBadge("STEERING", theme.Warning)
 		for _, msg := range m.steeringMessages {
-			content := msg + "\n" + badge
+			display := truncateMessageForBlock(msg, maxQueuedMessageLines, contentWidth)
+			content := display + "\n" + badge
 			rendered := renderContentBlock(
 				content,
 				m.width,
@@ -2492,7 +2523,8 @@ func (m *AppModel) renderQueuedMessages() string {
 	if len(m.queuedMessages) > 0 {
 		badge := style.CreateBadge("QUEUED", theme.Accent)
 		for _, msg := range m.queuedMessages {
-			content := msg + "\n" + badge
+			display := truncateMessageForBlock(msg, maxQueuedMessageLines, contentWidth)
+			content := display + "\n" + badge
 			rendered := renderContentBlock(
 				content,
 				m.width,
@@ -2506,6 +2538,58 @@ func (m *AppModel) renderQueuedMessages() string {
 	return strings.Join(blocks, "\n")
 }

+// truncateMessageForBlock truncates a message to at most maxLines visible
+// lines, accounting for soft-wrapping at the given width. If the message is
+// truncated, the last visible line is replaced with an ellipsis ("…").
+func truncateMessageForBlock(msg string, maxLines, width int) string {
+	if width <= 0 {
+		width = 1
+	}
+
+	lines := strings.Split(msg, "\n")
+
+	// Count visible lines (each hard line may wrap into multiple visual lines).
+	var kept []string
+	visibleCount := 0
+	truncated := false
+
+	for _, line := range lines {
+		// Calculate how many visual lines this hard line occupies.
+		lineWidth := lipgloss.Width(line)
+		wrapped := 1
+		if lineWidth > width {
+			wrapped = (lineWidth + width - 1) / width // ceil division
+		}
+
+		if visibleCount+wrapped > maxLines {
+			// This line would exceed the limit. Keep a partial if we
+			// still have room for at least one more visual line.
+			remaining := maxLines - visibleCount
+			if remaining > 0 {
+				// Truncate the line to fit the remaining visual lines.
+				runes := []rune(line)
+				maxRunes := remaining * width
+				if maxRunes < len(runes) {
+					kept = append(kept, string(runes[:maxRunes]))
+				} else {
+					kept = append(kept, line)
+				}
+			}
+			truncated = true
+			break
+		}
+
+		kept = append(kept, line)
+		visibleCount += wrapped
+	}
+
+	if !truncated {
+		return msg
+	}
+
+	return strings.Join(kept, "\n") + "…"
+}
+
 // --------------------------------------------------------------------------
 // Print helpers — add content to ScrollList
 // --------------------------------------------------------------------------
@@ -2876,7 +2960,7 @@ func (m *AppModel) printHelpMessage() {
 		"**Keys:**\n" +
 		"- `Ctrl+C`: Exit at any time\n" +
 		"- `ESC` (x2): Cancel ongoing LLM generation\n" +
-		"- `Ctrl+S`: Steer — redirect the agent mid-turn (injected between tool calls)\n" +
+		"- `Ctrl+X s`: Steer — redirect the agent mid-turn (injected between tool calls)\n" +
 		"- `Enter` (while working): Queue message for after the agent finishes\n\n" +
 		"You can also just type your message to chat with the AI assistant."
 	m.printSystemMessage(help)
@@ -2,6 +2,7 @@ package ui

 import (
 	"errors"
+	"strings"
 	"testing"

 	tea "charm.land/bubbletea/v2"
@@ -892,3 +893,107 @@ func TestSubmit_duringWorking_stays(t *testing.T) {
 		t.Fatalf("expected Run('queued prompt') called, got %v", ctrl.runCalls)
 	}
 }
+
+// --------------------------------------------------------------------------
+// truncateMessageForBlock
+// --------------------------------------------------------------------------
+
+// TestTruncateMessageForBlock_shortMessage verifies that short messages are
+// returned unchanged.
+func TestTruncateMessageForBlock_shortMessage(t *testing.T) {
+	msg := "hello world"
+	got := truncateMessageForBlock(msg, 3, 80)
+	if got != msg {
+		t.Fatalf("expected unchanged message, got %q", got)
+	}
+}
+
+// TestTruncateMessageForBlock_exactLines verifies that a message with exactly
+// maxLines hard lines is returned unchanged.
+func TestTruncateMessageForBlock_exactLines(t *testing.T) {
+	msg := "line1\nline2\nline3"
+	got := truncateMessageForBlock(msg, 3, 80)
+	if got != msg {
+		t.Fatalf("expected unchanged message, got %q", got)
+	}
+}
+
+// TestTruncateMessageForBlock_tooManyLines verifies that messages exceeding
+// maxLines are truncated with an ellipsis.
+func TestTruncateMessageForBlock_tooManyLines(t *testing.T) {
+	msg := "line1\nline2\nline3\nline4\nline5"
+	got := truncateMessageForBlock(msg, 3, 80)
+	want := "line1\nline2\nline3…"
+	if got != want {
+		t.Fatalf("expected %q, got %q", want, got)
+	}
+}
+
+// TestTruncateMessageForBlock_longWrappingLine verifies that a single long
+// line that would wrap beyond maxLines is truncated.
+func TestTruncateMessageForBlock_longWrappingLine(t *testing.T) {
+	// 100 chars at width 20 = 5 visual lines, exceeds maxLines=3
+	msg := "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+	got := truncateMessageForBlock(msg, 3, 20)
+	// Should be truncated to 3*20=60 runes + "…"
+	if len([]rune(got)) != 61 { // 60 runes + "…"
+		t.Fatalf("expected 61 runes (60 + ellipsis), got %d runes: %q", len([]rune(got)), got)
+	}
+	if got[len(got)-3:] != "…" { // "…" is 3 bytes in UTF-8
+		t.Fatal("expected trailing ellipsis")
+	}
+}
+
+// TestTruncateMessageForBlock_emptyMessage verifies that empty messages are
+// returned unchanged.
+func TestTruncateMessageForBlock_emptyMessage(t *testing.T) {
+	got := truncateMessageForBlock("", 3, 80)
+	if got != "" {
+		t.Fatalf("expected empty string, got %q", got)
+	}
+}
+
+// TestTruncateMessageForBlock_mixedWrapAndHardLines verifies truncation when
+// some hard lines wrap and the total exceeds maxLines.
+func TestTruncateMessageForBlock_mixedWrapAndHardLines(t *testing.T) {
+	// First line: 40 chars at width 20 = 2 visual lines
+	// Second line: "short" = 1 visual line (total: 3, exactly at limit)
+	// Third line: would exceed
+	msg := "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\nshort\nextra"
+	got := truncateMessageForBlock(msg, 3, 20)
+	want := "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\nshort…"
+	if got != want {
+		t.Fatalf("expected %q, got %q", want, got)
+	}
+}
+
+// TestRenderQueuedMessages_truncatesLongMessages verifies that the rendered
+// queued message view truncates long messages instead of showing them in full.
+func TestRenderQueuedMessages_truncatesLongMessages(t *testing.T) {
+	ctrl := &stubAppController{}
+	m, _, _ := newTestAppModel(ctrl)
+	m.width = 80
+
+	// Queue a very long message (20 lines).
+	var b strings.Builder
+	for i := range 20 {
+		if i > 0 {
+			b.WriteByte('\n')
+		}
+		b.WriteString("This is a long line of text for testing purposes")
+	}
+	m.queuedMessages = []string{b.String()}
+
+	rendered := m.renderQueuedMessages()
+	if rendered == "" {
+		t.Fatal("expected non-empty rendered output")
+	}
+
+	// The full message would be ~20+ lines. With truncation to 3 content
+	// lines + badge + padding, it should be much shorter.
+	lines := len(strings.Split(rendered, "\n"))
+	// 3 content lines + 1 badge + 2 padding + border overhead ≈ ~7 lines max
+	if lines > 10 {
+		t.Fatalf("expected truncated output to be ≤10 lines, got %d lines", lines)
+	}
+}
@@ -78,7 +78,7 @@ func newInputPrompt(message, placeholder, defaultValue string, width, height int
 	ta.Placeholder = placeholder
 	ta.ShowLineNumbers = false
 	ta.Prompt = ""
-	ta.CharLimit = 1000
+	ta.CharLimit = 0
 	ta.SetWidth(width - 12) // account for border + padding
 	ta.SetHeight(1)
 	ta.Focus()
@@ -14,11 +14,19 @@ import (
 )

 // UserBlock renders a user message with herald Tip styling.
-func UserBlock(content string, ty *herald.Typography, theme style.Theme) string {
+// The width parameter controls line wrapping so long messages don't overflow.
+func UserBlock(content string, width int, ty *herald.Typography, theme style.Theme) string {
 	if strings.TrimSpace(content) == "" {
 		content = "(empty message)"
 	}

+	// Wrap content before passing to herald Alert so long lines break
+	// inside the alert box. Subtract 4 to account for the alert bar
+	// prefix ("│ ") and a small margin.
+	if width > 4 {
+		content = lipgloss.Wrap(content, width-4, "")
+	}
+
 	rendered := ty.Tip(content)
 	return styleMarginBottom(theme, rendered)
 }
@@ -85,11 +85,13 @@ func GetMarkdownTypography() *herald.Typography {
 	return ty
 }

-// ToMarkdown renders markdown content using herald-md.
-// The width parameter is currently unused as herald handles wrapping
-// based on terminal width internally.
+// ToMarkdown renders markdown content using herald-md and wraps the result
+// to the given width so that long lines do not overflow the terminal.
 func ToMarkdown(content string, width int) string {
 	ty := GetMarkdownTypography()
 	rendered := heraldmd.Render(ty, []byte(content))
+	if width > 0 {
+		rendered = lipgloss.Wrap(rendered, width, "")
+	}
 	return rendered
 }
@@ -23,7 +23,7 @@ func NewToolApprovalInput(toolName, toolArgs string, width int) *ToolApprovalInp
 	ta := textarea.New()
 	ta.Placeholder = ""
 	ta.ShowLineNumbers = false
-	ta.CharLimit = 1000
+	ta.CharLimit = 0
 	ta.SetWidth(width - 8) // Account for container padding, border and internal padding
 	ta.SetHeight(4)        // Default to 3 lines like huh
 	ta.Focus()
@@ -68,8 +68,12 @@ host, err := kit.New(ctx, &kit.Options{
    NoSession:    true,                       // Ephemeral mode

    // Tool options
-    Tools:        []kit.Tool{kit.NewBashTool()}, // Replace default tool set
-    ExtraTools:   []kit.Tool{myTool},            // Add alongside defaults
+    Tools:            []kit.Tool{kit.NewBashTool()}, // Replace default tool set
+    ExtraTools:       []kit.Tool{myTool},            // Add alongside defaults
+    DisableCoreTools: true,                        // Use no core tools (0 tools)
+
+    // Configuration
+    SkipConfig:   true,                        // Skip .kit.yml files (viper defaults + env vars still apply)

    // Compaction
    AutoCompact:  true,                       // Auto-compact near context limit
@@ -172,6 +176,24 @@ msg  := kit.ConvertFromLLMMessage(lMsg)  // LLMMessage  → SDK Message
 - `GetSessionID()` - Get session UUID
 - `Close()` - Clean up resources

+### Options
+
+Key `Options` fields for SDK usage:
+
+| Field | Description |
+|-------|-------------|
+| `Model` | Override model (e.g., "anthropic/claude-sonnet-4-5-20250929") |
+| `SystemPrompt` | Override system prompt |
+| `ConfigFile` | Load specific config file (empty = search defaults) |
+| `SkipConfig` | Skip `.kit.yml` loading (defaults + env vars still apply) |
+| `Tools` | Replace core tools with custom set |
+| `ExtraTools` | Add tools alongside defaults |
+| `DisableCoreTools` | Use no core tools (0 tools, for chat-only) |
+| `NoSession` | Ephemeral mode (no session persistence) |
+| `SessionPath` | Open specific session file |
+| `Continue` | Resume most recent session |
+| `Debug` | Enable debug logging |
+
 ## Environment Variables

 All CLI environment variables work with the SDK:
@@ -0,0 +1,231 @@
+package kit
+
+import (
+	"strings"
+	"time"
+
+	"charm.land/fantasy"
+	"github.com/mark3labs/kit/internal/session"
+)
+
+// treeManagerAdapter adapts TreeManager to SessionManager interface.
+// This is unexported - users don't interact with it directly.
+type treeManagerAdapter struct {
+	inner *session.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 {
+	return &treeManagerAdapter{inner: tm}
+}
+
+// AppendMessage implements SessionManager.
+func (a *treeManagerAdapter) AppendMessage(msg LLMMessage) (string, error) {
+	// LLMMessage is just an alias for fantasy.Message, so no conversion needed
+	return a.inner.AppendLLMMessage(msg)
+}
+
+// GetMessages implements SessionManager.
+func (a *treeManagerAdapter) GetMessages() []LLMMessage {
+	// LLMMessage is just an alias for fantasy.Message
+	return a.inner.GetLLMMessages()
+}
+
+// BuildContext implements SessionManager.
+func (a *treeManagerAdapter) BuildContext() ([]LLMMessage, string, string) {
+	msgs, provider, modelID := a.inner.BuildContext()
+	return msgs, provider, modelID
+}
+
+// Branch implements SessionManager.
+func (a *treeManagerAdapter) Branch(entryID string) error {
+	return a.inner.Branch(entryID)
+}
+
+// GetCurrentBranch implements SessionManager.
+func (a *treeManagerAdapter) GetCurrentBranch() []BranchEntry {
+	branch := a.inner.GetBranch("")
+	var result []BranchEntry
+	for _, entry := range branch {
+		be := a.convertEntry(entry)
+		if be != nil {
+			result = append(result, *be)
+		}
+	}
+	return result
+}
+
+// GetChildren implements SessionManager.
+func (a *treeManagerAdapter) GetChildren(parentID string) []string {
+	return a.inner.GetChildren(parentID)
+}
+
+// GetEntry implements SessionManager.
+func (a *treeManagerAdapter) GetEntry(entryID string) *BranchEntry {
+	entry := a.inner.GetEntry(entryID)
+	if entry == nil {
+		return nil
+	}
+	return a.convertEntry(entry)
+}
+
+// GetSessionID implements SessionManager.
+func (a *treeManagerAdapter) GetSessionID() string {
+	return a.inner.GetSessionID()
+}
+
+// GetSessionName implements SessionManager.
+func (a *treeManagerAdapter) GetSessionName() string {
+	return a.inner.GetSessionName()
+}
+
+// SetSessionName implements SessionManager.
+func (a *treeManagerAdapter) SetSessionName(name string) error {
+	_, err := a.inner.AppendSessionInfo(name)
+	return err
+}
+
+// GetCreatedAt implements SessionManager.
+func (a *treeManagerAdapter) GetCreatedAt() time.Time {
+	return a.inner.GetHeader().Timestamp
+}
+
+// IsPersisted implements SessionManager.
+func (a *treeManagerAdapter) IsPersisted() bool {
+	return a.inner.IsPersisted()
+}
+
+// AppendCompaction implements SessionManager.
+func (a *treeManagerAdapter) AppendCompaction(summary string, firstKeptEntryID string,
+	tokensBefore, tokensAfter int, messagesRemoved int, readFiles, modifiedFiles []string) (string, error) {
+
+	return a.inner.AppendCompaction(summary, firstKeptEntryID,
+		tokensBefore, tokensAfter, messagesRemoved, readFiles, modifiedFiles)
+}
+
+// GetLastCompaction implements SessionManager.
+func (a *treeManagerAdapter) GetLastCompaction() *CompactionEntry {
+	c := a.inner.GetLastCompaction()
+	if c == nil {
+		return nil
+	}
+	return &CompactionEntry{
+		ID:               c.ID,
+		Summary:          c.Summary,
+		FirstKeptEntryID: c.FirstKeptEntryID,
+		TokensBefore:     c.TokensBefore,
+		TokensAfter:      c.TokensAfter,
+		MessagesRemoved:  c.MessagesRemoved,
+		ReadFiles:        c.ReadFiles,
+		ModifiedFiles:    c.ModifiedFiles,
+		Timestamp:        c.Timestamp,
+	}
+}
+
+// AppendExtensionData implements SessionManager.
+func (a *treeManagerAdapter) AppendExtensionData(extType, data string) (string, error) {
+	return a.inner.AppendExtensionData(extType, data)
+}
+
+// GetExtensionData implements SessionManager.
+func (a *treeManagerAdapter) GetExtensionData(extType string) []ExtensionDataEntry {
+	entries := a.inner.GetExtensionData(extType)
+	var result []ExtensionDataEntry
+	for _, e := range entries {
+		result = append(result, ExtensionDataEntry{
+			ID:        e.ID,
+			ExtType:   e.ExtType,
+			Data:      e.Data,
+			Timestamp: e.Timestamp,
+		})
+	}
+	return result
+}
+
+// AppendModelChange implements SessionManager.
+func (a *treeManagerAdapter) AppendModelChange(provider, modelID string) (string, error) {
+	return a.inner.AppendModelChange(provider, modelID)
+}
+
+// GetContextEntryIDs implements SessionManager.
+func (a *treeManagerAdapter) GetContextEntryIDs() []string {
+	return a.inner.GetContextEntryIDs()
+}
+
+// Close implements SessionManager.
+func (a *treeManagerAdapter) Close() error {
+	return a.inner.Close()
+}
+
+// Helper: Convert internal entry types to BranchEntry
+func (a *treeManagerAdapter) convertEntry(entry any) *BranchEntry {
+	switch e := entry.(type) {
+	case *session.MessageEntry:
+		msg, err := e.ToMessage()
+		if err != nil {
+			return nil
+		}
+		// Build content text from parts
+		var content strings.Builder
+		for _, part := range msg.Parts {
+			if textPart, ok := part.(TextContent); ok {
+				content.WriteString(textPart.Text)
+			}
+		}
+		return &BranchEntry{
+			ID:        e.ID,
+			ParentID:  e.ParentID,
+			Type:      EntryTypeMessage,
+			Role:      string(msg.Role),
+			Content:   content.String(),
+			Model:     e.Model,
+			Provider:  e.Provider,
+			Timestamp: e.Timestamp,
+			RawParts:  msg.Parts,
+		}
+	case *session.BranchSummaryEntry:
+		return &BranchEntry{
+			ID:        e.ID,
+			ParentID:  e.ParentID,
+			Type:      EntryTypeBranchSummary,
+			Content:   e.Summary,
+			Timestamp: e.Timestamp,
+		}
+	case *session.ModelChangeEntry:
+		return &BranchEntry{
+			ID:        e.ID,
+			ParentID:  e.ParentID,
+			Type:      EntryTypeModelChange,
+			Content:   "Model changed to " + e.Provider + "/" + e.ModelID,
+			Model:     e.ModelID,
+			Provider:  e.Provider,
+			Timestamp: e.Timestamp,
+		}
+	case *session.CompactionEntry:
+		return &BranchEntry{
+			ID:        e.ID,
+			ParentID:  e.ParentID,
+			Type:      EntryTypeCompaction,
+			Content:   e.Summary,
+			Timestamp: e.Timestamp,
+		}
+	case *session.ExtensionDataEntry:
+		return &BranchEntry{
+			ID:        e.ID,
+			ParentID:  e.ParentID,
+			Type:      EntryTypeExtensionData,
+			Content:   "Extension data: " + e.ExtType,
+			Timestamp: e.Timestamp,
+		}
+	default:
+		return nil
+	}
+}
+
+// convertKitMessagesToFantasy converts kit LLM messages to fantasy messages.
+// Since LLMMessage is an alias for fantasy.Message, this is a no-op.
+func convertKitMessagesToFantasy(msgs []LLMMessage) []fantasy.Message {
+	// LLMMessage is just an alias for fantasy.Message, so we can type convert
+	return msgs
+}
@@ -21,9 +21,9 @@ type ContextStats struct {
 const defaultReserveTokens = 16384

 // EstimateContextTokens returns the estimated token count of the current
-// conversation based on tree session messages.
+// conversation based on session messages.
 func (m *Kit) EstimateContextTokens() int {
-	messages := m.treeSession.GetLLMMessages()
+	messages := m.session.GetMessages()
 	return compaction.EstimateMessageTokens(messages)
 }

@@ -42,8 +42,8 @@ func (m *Kit) ShouldCompact() bool {
 		reserveTokens = m.compactionOpts.ReserveTokens
 	}

-	messages := m.treeSession.GetLLMMessages()
-	return compaction.ShouldCompact(messages, info.Limit.Context, reserveTokens)
+	messages := m.session.GetMessages()
+	return compaction.ShouldCompact(convertKitMessagesToFantasy(messages), info.Limit.Context, reserveTokens)
 }

 // GetContextStats returns current context usage statistics including
@@ -55,7 +55,7 @@ func (m *Kit) ShouldCompact() bool {
 // because it includes system prompts, tool definitions, and other overhead
 // that the heuristic cannot account for.
 func (m *Kit) GetContextStats() ContextStats {
-	messages := m.treeSession.GetLLMMessages()
+	messages := m.session.GetMessages()

 	// Prefer the real API-reported input token count when available.
 	m.lastInputTokensMu.RLock()
@@ -114,7 +114,7 @@ func (m *Kit) compactInternal(ctx context.Context, opts *CompactionOptions, cust
 		}
 	}

-	messages := m.treeSession.GetLLMMessages()
+	messages := m.session.GetMessages()
 	if len(messages) < 2 {
 		return nil, fmt.Errorf("cannot compact: need at least 2 messages")
 	}
@@ -145,7 +145,7 @@ func (m *Kit) compactInternal(ctx context.Context, opts *CompactionOptions, cust

 	// Carry forward file tracking from previous compaction.
 	var prev *compaction.PreviousCompaction
-	if lastCompaction := m.treeSession.GetLastCompaction(); lastCompaction != nil {
+	if lastCompaction := m.session.GetLastCompaction(); lastCompaction != nil {
 		prev = &compaction.PreviousCompaction{
 			ReadFiles:     lastCompaction.ReadFiles,
 			ModifiedFiles: lastCompaction.ModifiedFiles,
@@ -171,7 +171,7 @@ func (m *Kit) compactInternal(ctx context.Context, opts *CompactionOptions, cust

 	// Non-destructive: append a CompactionEntry to the session tree instead
 	// of clearing and rewriting messages.
-	entryIDs := m.treeSession.GetContextEntryIDs()
+	entryIDs := m.session.GetContextEntryIDs()
 	firstKeptEntryID := ""
 	if result.CutPoint >= 0 && result.CutPoint < len(entryIDs) {
 		firstKeptEntryID = entryIDs[result.CutPoint]
@@ -188,9 +188,9 @@ func (m *Kit) compactInternal(ctx context.Context, opts *CompactionOptions, cust
 // custom summary. It still determines the cut point and persists a
 // CompactionEntry.
 func (m *Kit) applyCustomCompaction(summary string, messages []LLMMessage, opts *CompactionOptions) (*CompactionResult, error) {
-	originalTokens := compaction.EstimateMessageTokens(messages)
+	originalTokens := compaction.EstimateMessageTokens(convertKitMessagesToFantasy(messages))

-	cutPoint := compaction.FindCutPoint(messages, opts.KeepRecentTokens)
+	cutPoint := compaction.FindCutPoint(convertKitMessagesToFantasy(messages), opts.KeepRecentTokens)
 	if cutPoint == 0 {
 		cutPoint = len(messages) - 1
 		if cutPoint < 1 {
@@ -198,7 +198,7 @@ func (m *Kit) applyCustomCompaction(summary string, messages []LLMMessage, opts
 		}
 	}

-	entryIDs := m.treeSession.GetContextEntryIDs()
+	entryIDs := m.session.GetContextEntryIDs()
 	firstKeptEntryID := ""
 	if cutPoint >= 0 && cutPoint < len(entryIDs) {
 		firstKeptEntryID = entryIDs[cutPoint]
@@ -234,7 +234,7 @@ func (m *Kit) persistAndEmitCompaction(
 	originalTokens, compactedTokens, messagesRemoved int,
 	readFiles, modifiedFiles []string,
 ) error {
-	if _, err := m.treeSession.AppendCompaction(
+	if _, err := m.session.AppendCompaction(
 		summary,
 		firstKeptEntryID,
 		originalTokens,
@@ -227,28 +227,51 @@ func (e *extensionAPI) GetMessageRenderer(name string) *extensions.MessageRender
 // Session data

 func (e *extensionAPI) GetSessionMessages() []extensions.SessionMessage {
-	return iterBranchMessages(e.kit.treeSession, func(me *session.MessageEntry, msg message.Message) extensions.SessionMessage {
-		return extensions.SessionMessage{
-			ID:        me.ID,
-			Role:      string(msg.Role),
-			Content:   msg.Content(),
-			Timestamp: me.Timestamp.Format("2006-01-02T15:04:05Z07:00"),
+	if e.kit.session == nil {
+		return nil
+	}
+
+	// Try to use the legacy iterBranchMessages for backward compatibility
+	// with the default TreeManager adapter
+	if adapter, ok := e.kit.session.(*treeManagerAdapter); ok {
+		return iterBranchMessages(adapter.inner, func(me *session.MessageEntry, msg message.Message) extensions.SessionMessage {
+			return extensions.SessionMessage{
+				ID:        me.ID,
+				Role:      string(msg.Role),
+				Content:   msg.Content(),
+				Timestamp: me.Timestamp.Format("2006-01-02T15:04:05Z07:00"),
+			}
+		})
+	}
+
+	// For custom SessionManagers, use the public interface
+	branch := e.kit.session.GetCurrentBranch()
+	var result []extensions.SessionMessage
+	for _, entry := range branch {
+		if entry.Type == EntryTypeMessage {
+			result = append(result, extensions.SessionMessage{
+				ID:        entry.ID,
+				Role:      entry.Role,
+				Content:   entry.Content,
+				Timestamp: entry.Timestamp.Format("2006-01-02T15:04:05Z07:00"),
+			})
 		}
-	})
+	}
+	return result
 }

 func (e *extensionAPI) AppendEntry(extType, data string) (string, error) {
-	if e.kit.treeSession == nil {
+	if e.kit.session == nil {
 		return "", fmt.Errorf("no session available")
 	}
-	return e.kit.treeSession.AppendExtensionData(extType, data)
+	return e.kit.session.AppendExtensionData(extType, data)
 }

 func (e *extensionAPI) GetEntries(extType string) []extensions.ExtensionEntry {
-	if e.kit.treeSession == nil {
+	if e.kit.session == nil {
 		return nil
 	}
-	entries := e.kit.treeSession.GetExtensionData(extType)
+	entries := e.kit.session.GetExtensionData(extType)
 	result := make([]extensions.ExtensionEntry, 0, len(entries))
 	for _, e := range entries {
 		result = append(result, extensions.ExtensionEntry{
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"log"
 	"os"
 	"path/filepath"
 	"strings"
@@ -11,7 +12,6 @@ import (
 	"time"

 	"charm.land/fantasy"
-	charmlog "github.com/charmbracelet/log"

 	"github.com/mark3labs/kit/internal/agent"
 	"github.com/mark3labs/kit/internal/config"
@@ -39,7 +39,7 @@ type ContextFile struct {
 // agents, sessions, and model configurations.
 type Kit struct {
 	agent          *agent.Agent
-	treeSession    *session.TreeManager
+	session        SessionManager
 	modelString    string
 	events         *eventBus
 	autoCompact    bool
@@ -172,27 +172,39 @@ type StructuredMessage struct {
 // flattens all content to a single text string, this preserves tool calls,
 // tool results, reasoning blocks, and finish markers as distinct typed parts.
 func (m *Kit) GetStructuredMessages() []StructuredMessage {
-	return iterBranchMessages(m.treeSession, func(me *session.MessageEntry, msg message.Message) StructuredMessage {
-		return StructuredMessage{
-			ID:        me.ID,
-			ParentID:  me.ParentID,
-			Role:      msg.Role,
-			Parts:     msg.Parts,
-			Model:     msg.Model,
-			Provider:  msg.Provider,
-			Timestamp: me.Timestamp.Format("2006-01-02T15:04:05Z07:00"),
+	if m.session == nil {
+		return nil
+	}
+
+	branch := m.session.GetCurrentBranch()
+	var results []StructuredMessage
+	for _, entry := range branch {
+		if entry.Type != EntryTypeMessage {
+			continue
 		}
-	})
+		results = append(results, StructuredMessage{
+			ID:        entry.ID,
+			ParentID:  entry.ParentID,
+			Role:      MessageRole(entry.Role),
+			Parts:     entry.RawParts,
+			Model:     entry.Model,
+			Provider:  entry.Provider,
+			Timestamp: entry.Timestamp.Format("2006-01-02T15:04:05Z07:00"),
+		})
+	}
+	return results
 }

 // iterBranchMessages iterates over the current branch's MessageEntry items,
 // converting each to a message.Message and calling fn to build the result.
-// Returns nil if there is no tree session. Skips entries that are not
+// Returns nil if there is no session. Skips entries that are not
 // MessageEntry or that fail conversion.
+// Deprecated: Use SessionManager.GetCurrentBranch() directly.
 func iterBranchMessages[T any](tm *session.TreeManager, fn func(*session.MessageEntry, message.Message) T) []T {
 	if tm == nil {
 		return nil
 	}
+
 	branch := tm.GetBranch("")
 	var results []T
 	for _, entry := range branch {
@@ -445,6 +457,17 @@ type Options struct {
 	Tools        []Tool // Custom tool set. If empty, AllTools() is used.
 	ExtraTools   []Tool // Additional tools added alongside core/MCP/extension tools.

+	// SkipConfig, when true, skips loading .kit.yml configuration files.
+	// Viper defaults (setSDKDefaults) and environment variables (KIT_*)
+	// are still applied. Use this for fully programmatic configuration.
+	SkipConfig bool
+
+	// DisableCoreTools, when true, prevents loading any core tools.
+	// Use with Tools or ExtraTools to provide only custom tools.
+	// If both DisableCoreTools is true and Tools is empty, the agent
+	// will have no tools (useful for simple chat completions).
+	DisableCoreTools bool
+
 	// Session configuration
 	SessionDir  string // Base directory for session discovery (default: cwd)
 	SessionPath string // Open a specific session file by path
@@ -483,6 +506,11 @@ type Options struct {

 	// CLI is optional CLI-specific configuration. SDK users leave this nil.
 	CLI *CLIOptions
+
+	// SessionManager allows custom session storage backends.
+	// If nil (default), Kit uses the built-in file-based TreeManager.
+	// When provided, SessionPath, Continue, and NoSession options are ignored.
+	SessionManager SessionManager
 }

 // CLIOptions holds fields only relevant to the CLI binary. SDK users should
@@ -577,7 +605,8 @@ func New(ctx context.Context, opts *Options) (*Kit, error) {
 		// Initialize config (loads config files and env vars).
 		// Only initialize if not already done (e.g., by CLI's cobra.OnInitialize).
 		// Check if model is already set, which indicates config was loaded.
-		if viper.GetString("model") == "" {
+		// SkipConfig bypasses .kit.yml file loading (viper defaults and env vars still apply).
+		if !opts.SkipConfig && viper.GetString("model") == "" {
 			if err := InitConfig(opts.ConfigFile, false); err != nil {
 				return fmt.Errorf("failed to initialize config: %w", err)
 			}
@@ -689,6 +718,7 @@ func New(ctx context.Context, opts *Options) (*Kit, error) {
 		MCPConfig:         mcpConfig,
 		Quiet:             opts.Quiet,
 		CoreTools:         opts.Tools,
+		DisableCoreTools:  opts.DisableCoreTools,
 		ExtraTools:        opts.ExtraTools,
 		ToolWrapper:       hookToolWrapper(beforeToolCall, afterToolResult),
 		ProviderConfig:    providerConfig,
@@ -709,7 +739,7 @@ func New(ctx context.Context, opts *Options) (*Kit, error) {
 		defaultHandler, authErr := NewDefaultMCPAuthHandler()
 		if authErr != nil {
 			// Non-fatal: OAuth just won't be available for remote servers.
-			charmlog.Warn("Failed to create OAuth handler; remote MCP servers requiring auth will fail", "error", authErr)
+			log.Printf("WARN Failed to create OAuth handler; remote MCP servers requiring auth will fail: %v", authErr)
 		} else {
 			setupOpts.AuthHandler = defaultHandler
 		}
@@ -727,16 +757,25 @@ func New(ctx context.Context, opts *Options) (*Kit, error) {
 		return nil, err
 	}

-	// Initialize tree session.
-	treeSession, err := InitTreeSession(opts)
-	if err != nil {
-		_ = agentResult.Agent.Close()
-		return nil, fmt.Errorf("failed to initialize session: %w", err)
+	// Initialize session manager.
+	var sessionManager SessionManager
+	if opts.SessionManager != nil {
+		// Use custom session manager provided by user.
+		sessionManager = opts.SessionManager
+	} else {
+		// DEFAULT: Use built-in TreeManager (existing behavior).
+		treeSession, err := InitTreeSession(opts)
+		if err != nil {
+			_ = agentResult.Agent.Close()
+			return nil, fmt.Errorf("failed to initialize session: %w", err)
+		}
+		// Wrap TreeManager in adapter to satisfy SessionManager interface.
+		sessionManager = NewTreeManagerAdapter(treeSession)
 	}

 	k := &Kit{
 		agent:           agentResult.Agent,
-		treeSession:     treeSession,
+		session:         sessionManager,
 		modelString:     modelString,
 		events:          newEventBus(),
 		autoCompact:     opts.AutoCompact,
@@ -1270,14 +1309,22 @@ func (m *Kit) generate(ctx context.Context, messages []fantasy.Message) (*agent.
 				IsStderr:   isStderr,
 			})
 		},
+		// Persist step messages incrementally so that progress survives
+		// crashes and long-running turns don't lose work. Each step's
+		// messages are persisted as a unit: for tool-calling steps this is
+		// the assistant message (with tool_use parts) + tool-role message
+		// (with tool_result parts) as a pair; for the final step it's the
+		// assistant text/reasoning message alone.
+		func(stepMessages []fantasy.Message) {
+			for _, msg := range stepMessages {
+				_, _ = m.session.AppendMessage(msg)
+			}
+		},
 		func(inputTokens, outputTokens, cacheReadTokens, cacheCreationTokens int64) {
 			// Emit step usage event for real-time cost tracking
 			if viper.GetBool("debug") {
-				charmlog.Debug("Kit.generate emitting StepUsageEvent",
-					"input", inputTokens,
-					"output", outputTokens,
-					"cacheRead", cacheReadTokens,
-					"cacheCreate", cacheCreationTokens,
+				log.Printf("DEBUG Kit.generate emitting StepUsageEvent: input=%d output=%d cacheRead=%d cacheCreate=%d",
+					inputTokens, outputTokens, cacheReadTokens, cacheCreationTokens,
 				)
 			}
 			m.events.emit(StepUsageEvent{
@@ -1295,11 +1342,17 @@ func (m *Kit) generate(ctx context.Context, messages []fantasy.Message) (*agent.
 //  2. Persist pre-generation messages to the tree session.
 //  3. Build context from the tree (walks leaf-to-root for current branch).
 //  4. Emit turn/message start events.
-//  5. Run generation.
-//  6. Emit turn/message end events.
-//  7. Persist post-generation messages (tool calls, results, assistant).
+//  5. Run generation (messages are persisted incrementally per step).
+//  6. Persist any remaining messages not covered by incremental persistence.
+//  7. Emit turn/message end events.
 //  8. Run AfterTurn hooks.
 //
+// During generation, each completed step's messages are persisted immediately
+// via the onStepMessages callback. Tool calls are always persisted as
+// call/response pairs (assistant + tool messages together). Reasoning and
+// text-only assistant messages are persisted as soon as their step completes.
+// This ensures long-running turns don't lose progress on crash or cancellation.
+//
 // promptLabel is the human-readable label emitted in TurnStartEvent.Prompt.
 // prompt is the raw user text passed to BeforeTurn hooks.
 func (m *Kit) runTurn(ctx context.Context, promptLabel string, prompt string, preMessages []fantasy.Message) (*TurnResult, error) {
@@ -1344,9 +1397,9 @@ func (m *Kit) runTurn(ctx context.Context, promptLabel string, prompt string, pr
 		}
 	}

-	// Persist pre-generation messages to tree session.
+	// Persist pre-generation messages to session.
 	for _, msg := range preMessages {
-		_, _ = m.treeSession.AppendLLMMessage(msg)
+		_, _ = m.session.AppendMessage(msg)
 	}

 	// Auto-compact if enabled and conversation is near the context limit.
@@ -1354,8 +1407,8 @@ func (m *Kit) runTurn(ctx context.Context, promptLabel string, prompt string, pr
 		_, _ = m.compactInternal(ctx, m.compactionOpts, "", true) // best-effort, automatic
 	}

-	// Build context from the tree so only the current branch is sent.
-	messages := m.treeSession.GetLLMMessages()
+	// Build context from the session so only the current branch is sent.
+	messages, _, _ := m.session.BuildContext()

 	// Run ContextPrepare hooks — extensions can filter, reorder, or inject messages.
 	if hookResult := m.contextPrepare.run(ContextPrepareHook{Messages: messages}); hookResult != nil && hookResult.Messages != nil {
@@ -1369,16 +1422,18 @@ func (m *Kit) runTurn(ctx context.Context, promptLabel string, prompt string, pr

 	result, err := m.generate(ctx, messages)
 	if err != nil {
-		// Persist any messages from completed steps (tool call/result
-		// pairs) so partial progress is not lost. The agent layer only
-		// includes fully-paired tool_use + tool_result messages in
-		// completedStepMessages, so there are no orphaned entries that
-		// would break subsequent API requests. The user message and any
-		// completed work remain in the session; only the in-progress
-		// (pending) message or tool call is discarded.
-		if result != nil && len(result.ConversationMessages) > sentCount {
-			for _, msg := range result.ConversationMessages[sentCount:] {
-				_, _ = m.treeSession.AppendLLMMessage(msg)
+		// Persist any messages from completed steps that were NOT already
+		// persisted incrementally by the onStepMessages callback. The agent
+		// layer only includes fully-paired tool_use + tool_result messages
+		// in completedStepMessages, so there are no orphaned entries that
+		// would break subsequent API requests.
+		if result != nil {
+			newMessages := result.ConversationMessages[sentCount:]
+			alreadyPersisted := result.PersistedMessageCount
+			if alreadyPersisted < len(newMessages) {
+				for _, msg := range newMessages[alreadyPersisted:] {
+					_, _ = m.session.AppendMessage(msg)
+				}
 			}
 		}
 		m.events.emit(TurnEndEvent{Error: err})
@@ -1389,12 +1444,17 @@ func (m *Kit) runTurn(ctx context.Context, promptLabel string, prompt string, pr

 	responseText := result.FinalResponse.Content.Text()

-	// Persist new messages (tool calls, tool results, assistant response)
-	// BEFORE emitting events so that extension handlers calling
-	// GetContextStats() see up-to-date token counts.
+	// Persist any new messages that were NOT already persisted incrementally
+	// by the onStepMessages callback during generation. This handles the
+	// non-streaming path (where onStepMessages is not called) and any edge
+	// cases where the final response messages weren't covered by step callbacks.
 	if len(result.ConversationMessages) > sentCount {
-		for _, msg := range result.ConversationMessages[sentCount:] {
-			_, _ = m.treeSession.AppendLLMMessage(msg)
+		newMessages := result.ConversationMessages[sentCount:]
+		alreadyPersisted := result.PersistedMessageCount
+		if alreadyPersisted < len(newMessages) {
+			for _, msg := range newMessages[alreadyPersisted:] {
+				_, _ = m.session.AppendMessage(msg)
+			}
 		}
 	}

@@ -1476,7 +1536,7 @@ func (m *Kit) Steer(ctx context.Context, instruction string) (string, error) {
 // Returns an error if there are no previous messages in the session.
 func (m *Kit) FollowUp(ctx context.Context, text string) (string, error) {
 	// Verify there is conversation history to follow up on.
-	if len(m.treeSession.GetLLMMessages()) == 0 {
+	if len(m.session.GetMessages()) == 0 {
 		return "", fmt.Errorf("cannot follow up: no previous messages")
 	}

@@ -1632,10 +1692,12 @@ func (m *Kit) PromptResultWithMessages(ctx context.Context, messages []string) (
 	return m.runTurn(ctx, promptLabel, messages[len(messages)-1], preMessages)
 }

-// ClearSession resets the tree session's leaf pointer to the root, starting
+// ClearSession resets the session's leaf pointer to the root, starting
 // a fresh conversation branch.
 func (m *Kit) ClearSession() {
-	m.treeSession.ResetLeaf()
+	if m.session != nil {
+		_ = m.session.Branch("")
+	}
 }

 // GetModelString returns the current model string identifier (e.g.,
@@ -1704,8 +1766,8 @@ func (m *Kit) Close() error {
 	if m.extRunner != nil && m.extRunner.HasHandlers(extensions.SessionShutdown) {
 		_, _ = m.extRunner.Emit(extensions.SessionShutdownEvent{})
 	}
-	if m.treeSession != nil {
-		_ = m.treeSession.Close()
+	if m.session != nil {
+		_ = m.session.Close()
 	}
 	// Release the OAuth callback port if we own the handler.
 	if closer, ok := m.authHandler.(interface{ Close() error }); ok {
@@ -1713,3 +1775,5 @@ func (m *Kit) Close() error {
 	}
 	return m.agent.Close()
 }
+
+// Conversion helpers are defined in adapter.go.
@@ -0,0 +1,144 @@
+package kit
+
+import (
+	"time"
+)
+
+// SessionManager defines the contract for conversation storage backends.
+// Implementations can use files (default), databases, cloud storage, etc.
+//
+// Implementations must be safe for concurrent use. During generation,
+// AppendMessage is called incrementally from the agent's step-completion
+// callback while read methods (GetMessages, GetCurrentBranch, etc.) may be
+// called concurrently from the UI or extension goroutines.
+type SessionManager interface {
+	// AppendMessage adds a message to the current branch and returns its entry ID.
+	// The entry ID is used for tree navigation and must be unique within the session.
+	//
+	// During generation, AppendMessage is called incrementally after each
+	// completed agent step rather than in a batch at the end of the turn.
+	// For tool-calling steps, the assistant message (containing tool_use parts)
+	// and the tool-role message (containing tool_result parts) are appended
+	// together as a pair. This ensures the session never contains an orphaned
+	// tool call without its result, which would break subsequent LLM requests.
+	AppendMessage(msg LLMMessage) (entryID string, err error)
+
+	// GetMessages returns all messages on the current branch (from root to leaf),
+	// including any compaction summaries at the appropriate positions.
+	GetMessages() []LLMMessage
+
+	// BuildContext returns the message history to send to the LLM, applying
+	// compaction rules and branch summaries as needed.
+	// Returns: messages, currentProvider, currentModelID
+	BuildContext() (messages []LLMMessage, provider string, modelID string)
+
+	// Branch moves the leaf pointer to the given entry ID, creating a branch point.
+	// Subsequent AppendMessage calls extend from this new position.
+	// entryID can be empty to reset to root (new conversation branch).
+	Branch(entryID string) error
+
+	// GetCurrentBranch returns the path from root to current leaf as entry metadata.
+	// Used for UI display and navigation.
+	GetCurrentBranch() []BranchEntry
+
+	// GetChildren returns direct child entry IDs for a given parent entry.
+	// Used to display branch points in the conversation tree.
+	GetChildren(parentID string) []string
+
+	// GetEntry returns a specific entry by ID, or nil if not found.
+	GetEntry(entryID string) *BranchEntry
+
+	// GetSessionID returns the unique session identifier (UUID).
+	GetSessionID() string
+
+	// GetSessionName returns the user-defined display name, or empty.
+	GetSessionName() string
+
+	// SetSessionName sets a display name for the session.
+	SetSessionName(name string) error
+
+	// GetCreatedAt returns when the session was created.
+	GetCreatedAt() time.Time
+
+	// IsPersisted returns true if this session writes to durable storage.
+	IsPersisted() bool
+
+	// AppendCompaction adds a compaction entry that summarizes older messages.
+	// firstKeptEntryID is the ID of the first message to preserve in context.
+	// readFiles and modifiedFiles track file changes for the compaction summary.
+	AppendCompaction(summary string, firstKeptEntryID string,
+		tokensBefore, tokensAfter int, messagesRemoved int, readFiles, modifiedFiles []string) (string, error)
+
+	// GetLastCompaction returns the most recent compaction entry on the current
+	// branch, or nil if none exists.
+	GetLastCompaction() *CompactionEntry
+
+	// AppendExtensionData stores custom extension data in the session tree.
+	// Extensions use this to persist state across restarts.
+	AppendExtensionData(extType, data string) (string, error)
+
+	// GetExtensionData returns all extension data entries of the given type
+	// on the current branch. If extType is empty, returns all extension data.
+	GetExtensionData(extType string) []ExtensionDataEntry
+
+	// AppendModelChange records a provider/model switch in the session.
+	AppendModelChange(provider, modelID string) (string, error)
+
+	// GetContextEntryIDs returns the entry IDs corresponding to the messages
+	// returned by BuildContext, in the same order. Used by compaction to
+	// determine which entries to summarize.
+	GetContextEntryIDs() []string
+
+	// Close releases resources (database connections, file handles, etc.).
+	Close() error
+}
+
+// BranchEntry represents a single node in the conversation tree.
+// This is a SDK-friendly struct (not the internal entry types).
+type BranchEntry struct {
+	ID        string
+	ParentID  string
+	Type      EntryType // "message", "branch_summary", "model_change", "compaction", "extension_data"
+	Role      string    // for messages: "user", "assistant", "system", "tool"
+	Content   string    // text content or summary
+	Model     string    // model used (for messages and model_change)
+	Provider  string    // provider used
+	Timestamp time.Time
+	Children  []string // child entry IDs (for tree display)
+
+	// RawParts contains the full typed content parts for structured access.
+	// Only populated for message entries.
+	RawParts []ContentPart
+}
+
+// EntryType identifies the kind of entry in the session tree.
+type EntryType string
+
+const (
+	EntryTypeMessage       EntryType = "message"
+	EntryTypeBranchSummary EntryType = "branch_summary"
+	EntryTypeModelChange   EntryType = "model_change"
+	EntryTypeCompaction    EntryType = "compaction"
+	EntryTypeExtensionData EntryType = "extension_data"
+)
+
+// CompactionEntry represents a context compaction/summarization event.
+type CompactionEntry struct {
+	ID               string
+	Summary          string
+	FirstKeptEntryID string
+	TokensBefore     int
+	TokensAfter      int
+	MessagesRemoved  int
+	ReadFiles        []string
+	ModifiedFiles    []string
+	Timestamp        time.Time
+}
+
+// ExtensionDataEntry represents custom extension data stored in the session.
+type ExtensionDataEntry struct {
+	ID        string
+	ExtType   string
+	Data      string
+	Timestamp time.Time
+}
@@ -8,7 +8,6 @@ import (
 	"time"

 	"github.com/mark3labs/kit/internal/extensions"
-	"github.com/mark3labs/kit/internal/message"
 	"github.com/mark3labs/kit/internal/session"
 )

@@ -47,49 +46,73 @@ func OpenTreeSession(path string) (*TreeManager, error) {

 // --- Instance methods on Kit ---

+// GetSessionManager returns the session manager, or nil if not configured.
+func (m *Kit) GetSessionManager() SessionManager {
+	return m.session
+}
+
 // GetTreeSession returns the tree session manager, or nil if not configured.
+// Deprecated: Use GetSessionManager instead.
 func (m *Kit) GetTreeSession() *TreeManager {
-	return m.treeSession
+	// Try to unwrap the adapter if using default implementation
+	if adapter, ok := m.session.(*treeManagerAdapter); ok {
+		return adapter.inner
+	}
+	return nil
+}
+
+// SetSessionManager replaces the session manager on a Kit instance.
+func (m *Kit) SetSessionManager(sm SessionManager) {
+	m.session = sm
 }

 // SetTreeSession replaces the tree session on a Kit instance. This is used by
 // the CLI when it handles session creation externally (e.g. --resume with a
 // TUI picker) and needs to inject the result into a Kit-like workflow.
+// Deprecated: Use SetSessionManager instead.
 func (m *Kit) SetTreeSession(ts *TreeManager) {
-	m.treeSession = ts
+	m.session = NewTreeManagerAdapter(ts)
 }

-// GetSessionPath returns the file path of the active tree session, or empty
-// for in-memory sessions or when no tree session is configured.
+// GetSessionPath returns the file path of the active session, or empty
+// for in-memory sessions or when no file-based session is configured.
 func (m *Kit) GetSessionPath() string {
-	if m.treeSession != nil {
-		return m.treeSession.GetFilePath()
+	// Only file-based sessions have a path
+	// Try to get it from the underlying TreeManager if using default adapter
+	if m.session == nil {
+		return ""
+	}
+	// Check if it's the default adapter
+	if adapter, ok := m.session.(*treeManagerAdapter); ok {
+		return adapter.inner.GetFilePath()
 	}
 	return ""
 }

-// GetSessionID returns the UUID of the active tree session, or empty when no
-// tree session is configured.
+// GetSessionID returns the UUID of the active session, or empty when no
+// session is configured.
 func (m *Kit) GetSessionID() string {
-	if m.treeSession != nil {
-		return m.treeSession.GetSessionID()
+	if m.session == nil {
+		return ""
 	}
-	return ""
+	return m.session.GetSessionID()
 }

-// Branch moves the tree session's leaf pointer to the given entry ID, creating
+// Branch moves the session's leaf pointer to the given entry ID, creating
 // a branch point. Subsequent Prompt() calls will extend from the new position.
 func (m *Kit) Branch(entryID string) error {
-	return m.treeSession.Branch(entryID)
+	if m.session == nil {
+		return fmt.Errorf("no session available")
+	}
+	return m.session.Branch(entryID)
 }

-// SetSessionName sets a user-defined display name for the active tree session.
+// SetSessionName sets a user-defined display name for the active session.
 func (m *Kit) SetSessionName(name string) error {
-	if m.treeSession == nil {
-		return fmt.Errorf("session naming requires a tree session")
+	if m.session == nil {
+		return fmt.Errorf("session naming requires a session")
 	}
-	_, err := m.treeSession.AppendSessionInfo(name)
-	return err
+	return m.session.SetSessionName(name)
 }

 // ---------------------------------------------------------------------------
@@ -97,27 +120,27 @@ func (m *Kit) SetSessionName(name string) error {
 // ---------------------------------------------------------------------------

 // GetTreeNode returns a node by ID with full metadata and children.
-// Returns nil if entry not found or no tree session.
+// Returns nil if entry not found or no session.
 func (m *Kit) GetTreeNode(entryID string) *TreeNode {
-	if m.treeSession == nil {
+	if m.session == nil {
 		return nil
 	}
-	entry := m.treeSession.GetEntry(entryID)
+	entry := m.session.GetEntry(entryID)
 	if entry == nil {
 		return nil
 	}
-	return m.entryToTreeNode(entry)
+	return m.branchEntryToTreeNode(entry)
 }

 // GetCurrentBranch returns the path from root to current leaf as TreeNodes.
 func (m *Kit) GetCurrentBranch() []TreeNode {
-	if m.treeSession == nil {
+	if m.session == nil {
 		return nil
 	}
-	branch := m.treeSession.GetBranch("")
+	branch := m.session.GetCurrentBranch()
 	var nodes []TreeNode
 	for _, entry := range branch {
-		node := m.entryToTreeNode(entry)
+		node := m.branchEntryToTreeNode(&entry)
 		if node != nil {
 			nodes = append(nodes, *node)
 		}
@@ -127,34 +150,34 @@ func (m *Kit) GetCurrentBranch() []TreeNode {

 // GetChildren returns direct child IDs of an entry.
 func (m *Kit) GetChildren(parentID string) []string {
-	if m.treeSession == nil {
+	if m.session == nil {
 		return nil
 	}
-	return m.treeSession.GetChildren(parentID)
+	return m.session.GetChildren(parentID)
 }

 // NavigateTo branches/forks the session to the specified entry ID.
 // Returns an error if the session is unavailable or the entry ID is not found.
 func (m *Kit) NavigateTo(entryID string) error {
-	if m.treeSession == nil {
-		return fmt.Errorf("no tree session available")
+	if m.session == nil {
+		return fmt.Errorf("no session available")
 	}
-	return m.treeSession.Branch(entryID)
+	return m.session.Branch(entryID)
 }

 // SummarizeBranch uses the LLM to summarize the conversation between two
 // entry IDs. Returns the summary text, or an error if the range is invalid,
 // the session is unavailable, or the LLM call fails.
 func (m *Kit) SummarizeBranch(fromID, toID string) (string, error) {
-	if m.treeSession == nil {
-		return "", fmt.Errorf("no tree session available")
+	if m.session == nil {
+		return "", fmt.Errorf("no session available")
 	}

 	// Get the branch and find the range
-	branch := m.treeSession.GetBranch("")
+	branch := m.session.GetCurrentBranch()
 	var startIdx, endIdx = -1, -1
 	for i, entry := range branch {
-		id := m.treeSession.EntryID(entry)
+		id := entry.ID
 		if id == fromID {
 			startIdx = i
 		}
@@ -170,7 +193,7 @@ func (m *Kit) SummarizeBranch(fromID, toID string) (string, error) {
 	// Build text to summarize
 	var content strings.Builder
 	for i := startIdx; i <= endIdx; i++ {
-		node := m.entryToTreeNode(branch[i])
+		node := m.branchEntryToTreeNode(&branch[i])
 		if node != nil && node.Content != "" {
 			fmt.Fprintf(&content, "[%s] %s\n\n", node.Role, node.Content)
 		}
@@ -195,73 +218,81 @@ func (m *Kit) SummarizeBranch(fromID, toID string) (string, error) {
 // CollapseBranch replaces a branch range with a summary entry.
 // Returns an error if the session is unavailable or the operation fails.
 func (m *Kit) CollapseBranch(fromID, toID, summary string) error {
-	if m.treeSession == nil {
-		return fmt.Errorf("no tree session available")
+	if m.session == nil {
+		return fmt.Errorf("no session available")
 	}
-	_, err := m.treeSession.AppendBranchSummary(fromID, summary)
-	return err
+	// Note: This operation is not directly supported by SessionManager interface
+	// as it requires AppendBranchSummary which is TreeManager-specific.
+	// For custom SessionManagers, this would need to be implemented differently.
+	// For now, we try to use the underlying TreeManager if available.
+	if adapter, ok := m.session.(*treeManagerAdapter); ok {
+		_, err := adapter.inner.AppendBranchSummary(fromID, summary)
+		return err
+	}
+	return fmt.Errorf("CollapseBranch not supported by custom session manager")
 }

-// entryToTreeNode converts a session entry to a TreeNode.
-func (m *Kit) entryToTreeNode(entry any) *TreeNode {
-	switch e := entry.(type) {
-	case *session.MessageEntry:
-		msg, err := e.ToMessage()
-		if err != nil {
-			return nil
-		}
+// branchEntryToTreeNode converts a BranchEntry to a TreeNode.
+func (m *Kit) branchEntryToTreeNode(entry *BranchEntry) *TreeNode {
+	if entry == nil {
+		return nil
+	}
+
+	switch entry.Type {
+	case EntryTypeMessage:
+		// Build content from RawParts
 		var content strings.Builder
-		for _, p := range msg.Parts {
+		for _, p := range entry.RawParts {
 			switch pt := p.(type) {
-			case message.TextContent:
+			case TextContent:
 				content.WriteString(pt.Text)
-			case message.ReasoningContent:
+			case ReasoningContent:
 				content.WriteString(pt.Thinking)
-			case message.ToolCall:
+			case ToolCall:
 				fmt.Fprintf(&content, "[tool_call: %s]", pt.Name)
-			case message.ToolResult:
+			case ToolResult:
 				fmt.Fprintf(&content, "[tool_result: %s]", pt.Content)
 			}
 		}
 		return &TreeNode{
-			ID:        e.ID,
-			ParentID:  e.ParentID,
+			ID:        entry.ID,
+			ParentID:  entry.ParentID,
 			Type:      "message",
-			Role:      string(msg.Role),
+			Role:      entry.Role,
 			Content:   content.String(),
-			Model:     msg.Model,
-			Provider:  msg.Provider,
-			Timestamp: e.Timestamp.Format(time.RFC3339),
-			Children:  m.treeSession.GetChildren(e.ID),
+			Model:     entry.Model,
+			Provider:  entry.Provider,
+			Timestamp: entry.Timestamp.Format(time.RFC3339),
+			Children:  m.session.GetChildren(entry.ID),
 		}
-	case *session.BranchSummaryEntry:
+	case EntryTypeBranchSummary:
 		return &TreeNode{
-			ID:        e.ID,
-			ParentID:  e.ParentID,
+			ID:        entry.ID,
+			ParentID:  entry.ParentID,
 			Type:      "branch_summary",
-			Content:   e.Summary,
-			Timestamp: e.Timestamp.Format(time.RFC3339),
-			Children:  m.treeSession.GetChildren(e.ID),
+			Content:   entry.Content,
+			Timestamp: entry.Timestamp.Format(time.RFC3339),
+			Children:  m.session.GetChildren(entry.ID),
 		}
-	case *session.ModelChangeEntry:
+	case EntryTypeModelChange:
 		return &TreeNode{
-			ID:        e.ID,
-			ParentID:  e.ParentID,
+			ID:        entry.ID,
+			ParentID:  entry.ParentID,
 			Type:      "model_change",
-			Content:   fmt.Sprintf("Model changed to %s/%s", e.Provider, e.ModelID),
-			Model:     e.Provider + "/" + e.ModelID,
-			Provider:  e.Provider,
-			Timestamp: e.Timestamp.Format(time.RFC3339),
-			Children:  m.treeSession.GetChildren(e.ID),
+			Content:   entry.Content,
+			Model:     entry.Model,
+			Provider:  entry.Provider,
+			Timestamp: entry.Timestamp.Format(time.RFC3339),
+			Children:  m.session.GetChildren(entry.ID),
 		}
-	case *session.ExtensionDataEntry:
+	case EntryTypeExtensionData:
 		return &TreeNode{
-			ID:        e.ID,
-			ParentID:  e.ParentID,
+			ID:        entry.ID,
+			ParentID:  entry.ParentID,
 			Type:      "extension_data",
-			Content:   fmt.Sprintf("Extension data: %s", e.ExtType),
-			Timestamp: e.Timestamp.Format(time.RFC3339),
-			Children:  m.treeSession.GetChildren(e.ID),
+			Content:   entry.Content,
+			Timestamp: entry.Timestamp.Format(time.RFC3339),
+			Children:  m.session.GetChildren(entry.ID),
 		}
 	default:
 		return nil
@@ -1,6 +1,8 @@
 package kit

 import (
+	"context"
+
 	"charm.land/fantasy"

 	"github.com/mark3labs/kit/internal/core"
@@ -16,6 +18,123 @@ type ToolOption = core.ToolOption
 // If empty, os.Getwd() is used at execution time.
 var WithWorkDir = core.WithWorkDir

+// --- Custom tool creation ---
+
+// ToolOutput is the return value from custom tool handlers created with
+// [NewTool] or [NewParallelTool]. It provides a dependency-free way to
+// return results without importing the underlying LLM framework.
+type ToolOutput struct {
+	// Content is the text content returned to the LLM.
+	Content string
+
+	// IsError, when true, signals to the LLM that the tool call failed.
+	IsError bool
+
+	// Data contains optional binary data (images, audio, etc.).
+	Data []byte
+
+	// MediaType is the MIME type for binary Data (e.g. "image/png").
+	MediaType string
+
+	// Metadata is optional opaque metadata attached to the response.
+	// It is not sent to the LLM but may be consumed by hooks or the UI.
+	Metadata any
+}
+
+// TextResult creates a successful text [ToolOutput].
+func TextResult(content string) ToolOutput {
+	return ToolOutput{Content: content}
+}
+
+// ErrorResult creates an error [ToolOutput]. The LLM will see the content
+// as a tool error, allowing it to retry or adjust its approach.
+func ErrorResult(content string) ToolOutput {
+	return ToolOutput{Content: content, IsError: true}
+}
+
+// toolCallIDKey is the context key for the tool call ID.
+type toolCallIDKey struct{}
+
+// ToolCallIDFromContext extracts the tool call ID from the context.
+// The call ID is set automatically by [NewTool] and [NewParallelTool]
+// before invoking the handler. Returns an empty string if no ID is present.
+func ToolCallIDFromContext(ctx context.Context) string {
+	s, _ := ctx.Value(toolCallIDKey{}).(string)
+	return s
+}
+
+// NewTool creates a custom [Tool] with automatic JSON schema generation from
+// the TInput struct type. The handler receives a typed input (deserialized
+// from the LLM's JSON arguments) and returns a [ToolResult].
+//
+// Struct tags on TInput control the generated schema:
+//
+//	json:"name"         → parameter name
+//	description:"..."   → parameter description shown to the LLM
+//	enum:"a,b,c"        → restrict valid values
+//	omitempty            → marks the parameter as optional
+//
+// The tool call ID is injected into the context and can be retrieved with
+// [ToolCallIDFromContext].
+//
+// Example:
+//
+//	type WeatherInput struct {
+//	    City string `json:"city" description:"City name"`
+//	}
+//
+//	tool := kit.NewTool("get_weather", "Get weather for a city",
+//	    func(ctx context.Context, input WeatherInput) (kit.ToolResult, error) {
+//	        return kit.TextResult("72°F, sunny in " + input.City), nil
+//	    },
+//	)
+func NewTool[TInput any](name, description string, fn func(ctx context.Context, input TInput) (ToolOutput, error)) Tool {
+	return fantasy.NewAgentTool(name, description,
+		func(ctx context.Context, input TInput, call fantasy.ToolCall) (fantasy.ToolResponse, error) {
+			ctx = context.WithValue(ctx, toolCallIDKey{}, call.ID)
+			result, err := fn(ctx, input)
+			if err != nil {
+				return fantasy.NewTextErrorResponse(err.Error()), nil
+			}
+			resp := fantasy.ToolResponse{
+				Content:   result.Content,
+				IsError:   result.IsError,
+				Data:      result.Data,
+				MediaType: result.MediaType,
+			}
+			if result.Metadata != nil {
+				resp = fantasy.WithResponseMetadata(resp, result.Metadata)
+			}
+			return resp, nil
+		},
+	)
+}
+
+// NewParallelTool is like [NewTool] but marks the tool as safe for concurrent
+// execution alongside other tools. Use this when the tool has no side effects
+// or when concurrent calls are safe.
+func NewParallelTool[TInput any](name, description string, fn func(ctx context.Context, input TInput) (ToolOutput, error)) Tool {
+	return fantasy.NewParallelAgentTool(name, description,
+		func(ctx context.Context, input TInput, call fantasy.ToolCall) (fantasy.ToolResponse, error) {
+			ctx = context.WithValue(ctx, toolCallIDKey{}, call.ID)
+			result, err := fn(ctx, input)
+			if err != nil {
+				return fantasy.NewTextErrorResponse(err.Error()), nil
+			}
+			resp := fantasy.ToolResponse{
+				Content:   result.Content,
+				IsError:   result.IsError,
+				Data:      result.Data,
+				MediaType: result.MediaType,
+			}
+			if result.Metadata != nil {
+				resp = fantasy.WithResponseMetadata(resp, result.Metadata)
+			}
+			return resp, nil
+		},
+	)
+}
+
 // --- Individual tool constructors ---

 // NewReadTool creates a file-reading tool.
@@ -0,0 +1,119 @@
+package kit_test
+
+import (
+	"context"
+	"testing"
+
+	kit "github.com/mark3labs/kit/pkg/kit"
+)
+
+// TestNewTool_BasicTextResult verifies that NewTool creates a working tool
+// that returns text content via ToolOutput.
+func TestNewTool_BasicTextResult(t *testing.T) {
+	type Input struct {
+		Name string `json:"name"`
+	}
+
+	tool := kit.NewTool("greet", "Greet someone",
+		func(ctx context.Context, input Input) (kit.ToolOutput, error) {
+			return kit.TextResult("hello " + input.Name), nil
+		},
+	)
+
+	info := tool.Info()
+	if info.Name != "greet" {
+		t.Errorf("Info().Name = %q, want %q", info.Name, "greet")
+	}
+	if info.Description != "Greet someone" {
+		t.Errorf("Info().Description = %q, want %q", info.Description, "Greet someone")
+	}
+	if info.Parallel {
+		t.Error("NewTool should not mark tool as parallel")
+	}
+}
+
+// TestNewParallelTool_MarkedParallel verifies that NewParallelTool marks the
+// tool as safe for concurrent execution.
+func TestNewParallelTool_MarkedParallel(t *testing.T) {
+	type Input struct {
+		Query string `json:"query"`
+	}
+
+	tool := kit.NewParallelTool("search", "Search for things",
+		func(ctx context.Context, input Input) (kit.ToolOutput, error) {
+			return kit.TextResult("found: " + input.Query), nil
+		},
+	)
+
+	info := tool.Info()
+	if info.Name != "search" {
+		t.Errorf("Info().Name = %q, want %q", info.Name, "search")
+	}
+	if !info.Parallel {
+		t.Error("NewParallelTool should mark tool as parallel")
+	}
+}
+
+// TestTextResult verifies the TextResult convenience constructor.
+func TestTextResult(t *testing.T) {
+	r := kit.TextResult("ok")
+	if r.Content != "ok" {
+		t.Errorf("Content = %q, want %q", r.Content, "ok")
+	}
+	if r.IsError {
+		t.Error("TextResult should not set IsError")
+	}
+}
+
+// TestErrorResult verifies the ErrorResult convenience constructor.
+func TestErrorResult(t *testing.T) {
+	r := kit.ErrorResult("bad input")
+	if r.Content != "bad input" {
+		t.Errorf("Content = %q, want %q", r.Content, "bad input")
+	}
+	if !r.IsError {
+		t.Error("ErrorResult should set IsError")
+	}
+}
+
+// TestToolCallIDFromContext verifies round-trip context injection.
+func TestToolCallIDFromContext(t *testing.T) {
+	// Empty context returns empty string.
+	if id := kit.ToolCallIDFromContext(context.Background()); id != "" {
+		t.Errorf("expected empty string from bare context, got %q", id)
+	}
+}
+
+// TestToolOutput_Metadata verifies that metadata can be set on ToolOutput.
+func TestToolOutput_Metadata(t *testing.T) {
+	r := kit.ToolOutput{
+		Content:  "data",
+		Metadata: map[string]string{"key": "value"},
+	}
+	if r.Metadata == nil {
+		t.Error("expected non-nil Metadata")
+	}
+	m, ok := r.Metadata.(map[string]string)
+	if !ok {
+		t.Fatalf("expected map[string]string, got %T", r.Metadata)
+	}
+	if m["key"] != "value" {
+		t.Errorf("Metadata[key] = %q, want %q", m["key"], "value")
+	}
+}
+
+// TestToolOutput_BinaryData verifies that binary data fields work correctly.
+func TestToolOutput_BinaryData(t *testing.T) {
+	data := []byte{0x89, 0x50, 0x4E, 0x47}
+	r := kit.ToolOutput{
+		Content:   "image result",
+		Data:      data,
+		MediaType: "image/png",
+	}
+	if len(r.Data) != 4 {
+		t.Errorf("Data len = %d, want 4", len(r.Data))
+	}
+	if r.MediaType != "image/png" {
+		t.Errorf("MediaType = %q, want %q", r.MediaType, "image/png")
+	}
+}
@@ -85,10 +85,15 @@ host, err := kit.New(ctx, &kit.Options{
    SessionPath: "/path/to/session.jsonl", // open specific session file
    Continue:    true,                // resume most recent session for SessionDir
    NoSession:   true,                // ephemeral in-memory session, no disk persistence
+    SessionManager: myCustomSession,  // custom SessionManager implementation (advanced)

    // Tools
-    Tools:      []kit.Tool{kit.NewBashTool()}, // REPLACES entire default tool set
-    ExtraTools: []kit.Tool{myTool},            // ADDS alongside core/MCP/extension tools
+    Tools:            []kit.Tool{kit.NewBashTool()}, // REPLACES entire default tool set
+    ExtraTools:       []kit.Tool{myTool},            // ADDS alongside core/MCP/extension tools
+    DisableCoreTools: true,                        // Use no core tools (0 tools, for chat-only)
+
+    // Configuration
+    SkipConfig:   true,                        // Skip .kit.yml files (viper defaults + env vars still apply)

    // Skills
    Skills:    []string{"/path/to/skill.md"}, // explicit skill files (empty = auto-discover)
@@ -342,6 +347,77 @@ Lower values run first. Within the same priority, registration order applies. Fi

 ## Tools

+### Creating custom tools
+
+Use `kit.NewTool` to create custom tools. The JSON schema is auto-generated from the input struct — no external dependencies required:
+
+```go
+type WeatherInput struct {
+    City string `json:"city" description:"City name, e.g. 'San Francisco'"`
+}
+
+weatherTool := kit.NewTool("get_weather", "Get current weather for a city",
+    func(ctx context.Context, input WeatherInput) (kit.ToolOutput, error) {
+        // Your logic here (API calls, database lookups, etc.)
+        return kit.TextResult("72°F, sunny in " + input.City), nil
+    },
+)
+
+host, _ := kit.New(ctx, &kit.Options{
+    ExtraTools: []kit.Tool{weatherTool},
+})
+```
+
+**Struct tags** control the generated schema:
+
+| Tag | Purpose | Example |
+|-----|---------|---------|
+| `json:"name"` | Parameter name | `json:"city"` |
+| `description:"..."` | Description shown to the LLM | `description:"City name"` |
+| `enum:"a,b,c"` | Restrict valid values | `enum:"json,text,csv"` |
+| `omitempty` | Marks parameter as optional | `json:"limit,omitempty"` |
+
+**Return helpers:**
+
+| Function | Description |
+|----------|-------------|
+| `kit.TextResult(content)` | Successful text result |
+| `kit.ErrorResult(content)` | Error result (LLM sees it as a tool error) |
+
+**ToolOutput fields** (for advanced use):
+
+```go
+kit.ToolOutput{
+    Content:   "result text",     // text returned to the LLM
+    IsError:   false,             // true = LLM sees this as an error
+    Data:      pngBytes,          // optional binary data (images, audio)
+    MediaType: "image/png",       // MIME type for binary Data
+    Metadata:  map[string]any{},  // opaque metadata for hooks/UI (not sent to LLM)
+}
+```
+
+**Parallel tools** — mark as safe for concurrent execution:
+
+```go
+searchTool := kit.NewParallelTool("search", "Search the web",
+    func(ctx context.Context, input SearchInput) (kit.ToolOutput, error) {
+        return kit.TextResult("results..."), nil
+    },
+)
+```
+
+**Tool call ID** — available in context for logging/tracing:
+
+```go
+tool := kit.NewTool("my_tool", "...",
+    func(ctx context.Context, input MyInput) (kit.ToolOutput, error) {
+        callID := kit.ToolCallIDFromContext(ctx) // correlation ID from the LLM
+        log.Printf("[%s] my_tool called", callID)
+        return kit.TextResult("ok"), nil
+    },
+)
+```
+
 ### Built-in tool constructors

 ```go
@@ -431,6 +507,72 @@ kit.DeleteSession("/path/to/session.jsonl")
 tm, _ := kit.OpenTreeSession("/path/to/session.jsonl") // open for direct access
 ```

+### Custom Session Manager (Advanced)
+
+You can provide a custom session manager to store conversation history in your own backend (database, cloud storage, etc.) instead of the default JSONL files.
+
+```go
+// Implement the SessionManager interface
+type MyDatabaseSessionManager struct {
+    db *sql.DB
+    // ... other fields
+}
+
+func (s *MyDatabaseSessionManager) AppendMessage(msg kit.LLMMessage) (string, error) {
+    // Store message in your database
+}
+
+func (s *MyDatabaseSessionManager) GetMessages() []kit.LLMMessage {
+    // Retrieve messages from your database
+}
+
+// ... implement all other SessionManager methods
+
+// Use with Kit
+host, _ := kit.New(ctx, &kit.Options{
+    SessionManager: myCustomSession,  // Your custom implementation
+    Model: "anthropic/claude-sonnet-latest",
+})
+```
+
+**SessionManager Interface:**
+
+```go
+type SessionManager interface {
+    AppendMessage(msg kit.LLMMessage) (entryID string, err error)
+    GetMessages() []kit.LLMMessage
+    BuildContext() (messages []kit.LLMMessage, provider string, modelID string)
+    Branch(entryID string) error
+    GetCurrentBranch() []kit.BranchEntry
+    GetChildren(parentID string) []string
+    GetEntry(entryID string) *kit.BranchEntry
+    GetSessionID() string
+    GetSessionName() string
+    SetSessionName(name string) error
+    GetCreatedAt() time.Time
+    IsPersisted() bool
+    AppendCompaction(summary string, firstKeptEntryID string,
+        tokensBefore, tokensAfter int, messagesRemoved int, readFiles, modifiedFiles []string) (string, error)
+    GetLastCompaction() *kit.CompactionEntry
+    AppendExtensionData(extType, data string) (string, error)
+    GetExtensionData(extType string) []kit.ExtensionDataEntry
+    AppendModelChange(provider, modelID string) (string, error)
+    GetContextEntryIDs() []string
+    Close() error
+}
+```
+
+**Use Cases:**
+- **PocketBase integration**: Store sessions as PocketBase records
+- **Cloud storage**: Persist sessions to S3, GCS, or Azure Blob
+- **Multi-user apps**: Store sessions per user in a database
+- **Custom retention**: Implement your own session cleanup policies
+
+**Note:** When using a custom SessionManager, the following Options are ignored:
+- `SessionPath` - your manager handles its own storage
+- `Continue` - your manager handles session selection
+- `NoSession` - use an in-memory implementation instead
+
 ---

 ## Model Management
@@ -7,17 +7,16 @@ description: Monitor tool calls and streaming output with the Kit Go SDK.

 ## Event-based monitoring

-For more granular control, use the event subscription API:
+Subscribe to events for real-time monitoring. Each method returns an unsubscribe function:

 ```go
-// Subscribe returns an unsubscribe function
 unsub := host.OnToolCall(func(event kit.ToolCallEvent) {
-    fmt.Printf("Tool: %s, Args: %s\n", event.Name, event.Args)
+    fmt.Printf("Tool: %s, Args: %s\n", event.ToolName, event.ToolArgs)
 })
 defer unsub()

 unsub2 := host.OnToolResult(func(event kit.ToolResultEvent) {
-    fmt.Printf("Result: %s (error: %v)\n", event.Name, event.IsError)
+    fmt.Printf("Result: %s (error: %v)\n", event.ToolName, event.IsError)
 })
 defer unsub2()

@@ -44,33 +43,62 @@ defer unsub6()

 ## Hook system

-Hooks allow you to intercept and modify behavior. Unlike events, hooks can modify or cancel operations:
+Hooks can **modify or cancel** operations. Unlike events (read-only), hooks are read-write interceptors.
+
+### BeforeToolCall — block tool execution

 ```go
-// Intercept tool calls before execution
-host.OnBeforeToolCall(0, func(ctx context.Context, name string, args string) (string, error) {
-    if name == "bash" {
-        log.Println("Bash command:", args)
+host.OnBeforeToolCall(kit.HookPriorityNormal, func(h kit.BeforeToolCallHook) *kit.BeforeToolCallResult {
+    // h.ToolCallID, h.ToolName, h.ToolArgs
+    if h.ToolName == "bash" && strings.Contains(h.ToolArgs, "rm -rf") {
+        return &kit.BeforeToolCallResult{Block: true, Reason: "dangerous command"}
    }
-    return args, nil // return modified args or error to cancel
+    return nil // allow
 })
+```

-// Process results after tool execution
-host.OnAfterToolResult(0, func(ctx context.Context, name string, result string) (string, error) {
-    return result, nil
-})
+### AfterToolResult — modify tool output

-// Before/after each agent turn
-host.OnBeforeTurn(0, func(ctx context.Context) error {
-    return nil
-})
-
-host.OnAfterTurn(0, func(ctx context.Context) error {
+```go
+host.OnAfterToolResult(kit.HookPriorityNormal, func(h kit.AfterToolResultHook) *kit.AfterToolResultResult {
+    // h.ToolCallID, h.ToolName, h.ToolArgs, h.Result, h.IsError
+    if h.ToolName == "read" {
+        filtered := redactSecrets(h.Result)
+        return &kit.AfterToolResultResult{Result: &filtered}
+    }
    return nil
 })
 ```

-The first argument is a priority (lower = runs first).
+### BeforeTurn — modify prompt, inject messages
+
+```go
+host.OnBeforeTurn(kit.HookPriorityNormal, func(h kit.BeforeTurnHook) *kit.BeforeTurnResult {
+    // h.Prompt
+    newPrompt := h.Prompt + "\nAlways respond in JSON."
+    return &kit.BeforeTurnResult{Prompt: &newPrompt}
+    // Also available: SystemPrompt *string, InjectText *string
+})
+```
+
+### AfterTurn — observation only
+
+```go
+host.OnAfterTurn(kit.HookPriorityNormal, func(h kit.AfterTurnHook) {
+    // h.Response, h.Error
+    log.Printf("Turn completed: %d chars", len(h.Response))
+})
+```
+
+### Hook priorities
+
+```go
+kit.HookPriorityHigh   = 0   // runs first
+kit.HookPriorityNormal = 50  // default
+kit.HookPriorityLow    = 100 // runs last
+```
+
+Lower values run first. First non-nil result wins.

 ## Subagent event monitoring

@@ -29,8 +29,12 @@ host, err := kit.New(ctx, &kit.Options{
    NoSession:    true,

    // Tools
-    Tools:        []kit.Tool{...},     // Replace default tool set entirely
-    ExtraTools:   []kit.Tool{...},     // Add tools alongside defaults
+    Tools:            []kit.Tool{...},     // Replace default tool set entirely
+    ExtraTools:       []kit.Tool{...},     // Add tools alongside defaults
+    DisableCoreTools: true,                // Use no core tools (0 tools, for chat-only)
+
+    // Configuration
+    SkipConfig:   true,                   // Skip .kit.yml files (viper defaults + env vars still apply)

    // Compaction
    AutoCompact:  true,
@@ -58,7 +62,34 @@ host, err := kit.New(ctx, &kit.Options{
 | `NoSession` | `bool` | `false` | Ephemeral mode (no persistence) |
 | `Tools` | `[]Tool` | — | Replace the entire default tool set |
 | `ExtraTools` | `[]Tool` | — | Additional tools alongside core/MCP/extension tools |
+| `DisableCoreTools` | `bool` | `false` | Use no core tools (0 tools, for chat-only) |
+| `SkipConfig` | `bool` | `false` | Skip .kit.yml file loading |
 | `AutoCompact` | `bool` | `false` | Auto-compact when near context limit |
 | `CompactionOptions` | `*CompactionOptions` | — | Configuration for auto-compaction |
 | `Skills` | `[]string` | — | Explicit skill files/dirs to load |
 | `SkillsDir` | `string` | — | Override default skills directory |
+
+## Tool configuration
+
+**`Tools`** replaces ALL default tools (core + MCP + extension). **`ExtraTools`** adds tools alongside the defaults. Use `Tools` to restrict capabilities; use `ExtraTools` to extend them.
+
+Create custom tools with `kit.NewTool` — no external dependencies needed:
+
+```go
+type LookupInput struct {
+    ID string `json:"id" description:"Record ID to look up"`
+}
+
+lookupTool := kit.NewTool("lookup", "Look up a record by ID",
+    func(ctx context.Context, input LookupInput) (kit.ToolOutput, error) {
+        record := db.Find(input.ID)
+        return kit.TextResult(record.String()), nil
+    },
+)
+
+host, _ := kit.New(ctx, &kit.Options{
+    ExtraTools: []kit.Tool{lookupTool},
+})
+```
+
+See [Overview](/sdk/overview#custom-tools) for full custom tool documentation.
@@ -68,6 +68,44 @@ The SDK provides several prompt variants:
 | `Steer(ctx, instruction)` | System-level steering without user message |
 | `FollowUp(ctx, text)` | Continue without new user input |

+## Custom tools
+
+Create custom tools with `kit.NewTool`. The JSON schema is auto-generated from the input struct — no external dependencies required:
+
+```go
+type WeatherInput struct {
+    City string `json:"city" description:"City name"`
+}
+
+weatherTool := kit.NewTool("get_weather", "Get current weather for a city",
+    func(ctx context.Context, input WeatherInput) (kit.ToolOutput, error) {
+        return kit.TextResult("72°F, sunny in " + input.City), nil
+    },
+)
+
+host, _ := kit.New(ctx, &kit.Options{
+    ExtraTools: []kit.Tool{weatherTool},
+})
+```
+
+Struct tags control the schema:
+
+- `json:"name"` — parameter name
+- `description:"..."` — description shown to the LLM
+- `enum:"a,b,c"` — restrict valid values
+- `omitempty` — marks the parameter as optional
+
+Return values:
+
+| Helper | Description |
+|--------|-------------|
+| `kit.TextResult(s)` | Successful text result |
+| `kit.ErrorResult(s)` | Error result (LLM sees it as a tool error) |
+
+For advanced use, return a `kit.ToolOutput` struct directly with `Data`, `MediaType`, and `Metadata` fields.
+
+Use `kit.NewParallelTool` for tools that are safe to run concurrently. Use `kit.ToolCallIDFromContext(ctx)` to retrieve the LLM-assigned call ID for logging or tracing.
+
 ## Event system

 Subscribe to events for monitoring:
@@ -901,6 +901,126 @@ a:hover { text-decoration: underline; }
  color: var(--text-muted);
 }

+/* ============================================================
+   Compaction Card
+   ============================================================ */
+.compaction-card {
+  margin: 16px 0;
+  border: 1px solid var(--border);
+  border-radius: var(--radius);
+  background: var(--surface);
+  overflow: hidden;
+}
+
+.compaction-header {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 12px 16px;
+  cursor: pointer;
+  user-select: none;
+  transition: background var(--transition);
+  background: var(--surface-raised);
+}
+
+.compaction-header:hover {
+  background: var(--surface-overlay);
+}
+
+.compaction-icon {
+  width: 18px;
+  height: 18px;
+  color: var(--yellow);
+  flex-shrink: 0;
+}
+
+.compaction-title {
+  font-size: 13px;
+  font-weight: 600;
+  color: var(--text-secondary);
+  flex: 1;
+}
+
+.compaction-badge {
+  font-size: 11px;
+  font-weight: 500;
+  color: var(--text-muted);
+  background: var(--surface);
+  padding: 2px 8px;
+  border-radius: 10px;
+  border: 1px solid var(--border);
+}
+
+.compaction-chevron {
+  width: 16px;
+  height: 16px;
+  color: var(--text-faint);
+  transition: transform var(--transition);
+  flex-shrink: 0;
+}
+
+.compaction-card.expanded .compaction-chevron {
+  transform: rotate(180deg);
+}
+
+.compaction-content {
+  max-height: 0;
+  overflow: hidden;
+  transition: max-height var(--transition);
+  border-top: 1px solid transparent;
+}
+
+.compaction-card.expanded .compaction-content {
+  max-height: 2000px;
+  overflow-y: auto;
+  border-top-color: var(--border);
+}
+
+.compaction-summary {
+  padding: 16px;
+  font-size: 13.5px;
+  line-height: 1.7;
+  color: var(--text-secondary);
+}
+
+.compaction-summary .md-content h1,
+.compaction-summary .md-content h2,
+.compaction-summary .md-content h3 {
+  color: var(--text);
+  margin: 16px 0 8px;
+}
+
+.compaction-summary .md-content h1 { font-size: 1.3em; }
+.compaction-summary .md-content h2 { font-size: 1.15em; }
+.compaction-summary .md-content h3 { font-size: 1.05em; }
+
+.compaction-summary .md-content ul,
+.compaction-summary .md-content ol {
+  padding-left: 20px;
+}
+
+.compaction-stats {
+  display: flex;
+  gap: 16px;
+  padding: 12px 16px;
+  background: var(--surface-raised);
+  border-top: 1px solid var(--border-subtle);
+  font-size: 11.5px;
+  color: var(--text-muted);
+  flex-wrap: wrap;
+}
+
+.compaction-stat {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+}
+
+.compaction-stat strong {
+  color: var(--text-secondary);
+  font-weight: 600;
+}
+
 /* ============================================================
   System Prompt Display
   ============================================================ */
@@ -1460,6 +1580,7 @@ a:hover { text-decoration: underline; }
    let userMsgCount = 0;
    let assistantMsgCount = 0;
    let toolCallCount = 0;
+    let compactionCount = 0;

    // Render each entry
    for (const entry of path) {
@@ -1491,6 +1612,9 @@ a:hover { text-decoration: underline; }
        renderSystemNotice('Label', entry.label || '', 'label');
      } else if (entry.type === 'session_info') {
        // Already handled above for header
+      } else if (entry.type === 'compaction') {
+        compactionCount++;
+        renderCompaction(entry);
      }
    }

@@ -1501,6 +1625,7 @@ a:hover { text-decoration: underline; }
          <div class="stat-item"><strong>${userMsgCount}</strong> user message${userMsgCount !== 1 ? 's' : ''}</div>
          <div class="stat-item"><strong>${assistantMsgCount}</strong> assistant message${assistantMsgCount !== 1 ? 's' : ''}</div>
          ${toolCallCount > 0 ? `<div class="stat-item"><strong>${toolCallCount}</strong> tool call${toolCallCount !== 1 ? 's' : ''}</div>` : ''}
+          ${compactionCount > 0 ? `<div class="stat-item"><strong>${compactionCount}</strong> compaction${compactionCount !== 1 ? 's' : ''}</div>` : ''}
          ${header && header.cwd ? `<div class="stat-item">📁 ${escapeHtml(header.cwd)}</div>` : ''}
        </div>`;
      $conversation.insertAdjacentHTML('beforeend', statsHtml);
@@ -2030,6 +2155,60 @@ a:hover { text-decoration: underline; }
    $conversation.appendChild(el);
  }

+  // ============================================================
+  //  Compaction Display
+  // ============================================================
+  function renderCompaction(entry) {
+    const el = document.createElement('div');
+    el.className = 'compaction-card fade-in';
+    
+    const cardId = 'compaction-' + Math.random().toString(36).substr(2, 9);
+    
+    // Build stats
+    const stats = [];
+    if (entry.messages_removed > 0) {
+      stats.push(`<div class="compaction-stat"><strong>${entry.messages_removed}</strong> messages compacted</div>`);
+    }
+    if (entry.tokens_before > 0 && entry.tokens_after > 0) {
+      const saved = entry.tokens_before - entry.tokens_after;
+      stats.push(`<div class="compaction-stat"><strong>${saved}</strong> tokens saved</div>`);
+    }
+    
+    // Format timestamp
+    const timeStr = formatTime(entry.timestamp);
+    
+    el.innerHTML = `
+      <div class="compaction-header" onclick="toggleCompaction('${cardId}')">
+        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" fill="currentColor" class="compaction-icon">
+          <path d="M2.5 3.5a.5.5 0 0 1 .5-.5h10a.5.5 0 0 1 .5.5v1a.5.5 0 0 1-.5.5h-10a.5.5 0 0 1-.5-.5v-1Zm0 4a.5.5 0 0 1 .5-.5h10a.5.5 0 0 1 .5.5v1a.5.5 0 0 1-.5.5h-10a.5.5 0 0 1-.5-.5v-1Zm0 4a.5.5 0 0 1 .5-.5h10a.5.5 0 0 1 .5.5v1a.5.5 0 0 1-.5.5h-10a.5.5 0 0 1-.5-.5v-1Z"/>
+        </svg>
+        <span class="compaction-title">Context Compacted</span>
+        ${timeStr ? `<span class="compaction-badge">${timeStr}</span>` : ''}
+        <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" fill="currentColor" class="compaction-chevron" id="${cardId}-chevron">
+          <path d="M4.427 9.427a.25.25 0 0 0 0 .353l3 3a.25.25 0 0 0 .353 0l3-3a.25.25 0 0 0-.353-.353L8 11.646V4.75a.75.75 0 0 0-1.5 0v6.896L4.78 9.427a.25.25 0 0 0-.353 0Z"/>
+        </svg>
+      </div>
+      <div class="compaction-content" id="${cardId}">
+        ${entry.summary ? `<div class="compaction-summary"><div class="md-content">${renderMarkdown(entry.summary)}</div></div>` : ''}
+        ${stats.length > 0 ? `<div class="compaction-stats">${stats.join('')}</div>` : ''}
+      </div>`;
+    
+    $conversation.appendChild(el);
+  }
+
+  // Toggle compaction card expansion
+  window.toggleCompaction = function(cardId) {
+    const card = document.getElementById(cardId).closest('.compaction-card');
+    const chevron = document.getElementById(cardId + '-chevron');
+    const isExpanded = card.classList.contains('expanded');
+    
+    if (isExpanded) {
+      card.classList.remove('expanded');
+    } else {
+      card.classList.add('expanded');
+    }
+  };
+
  // ============================================================
  //  System Prompt Display (collapsible)
  // ============================================================
Author	SHA1	Message	Date
Ed Zynda	34bb97a40e	chore(deps): update dependencies - bump mcp-go to v0.47.1 - update cloud auth, otel, and various indirect deps	2026-04-08 20:51:59 +03:00
Ed Zynda	f5c1a16f8a	feat(session): make compaction create new leaf with no parent Change compaction behavior so the compaction entry has no parent (empty ParentID), creating a new root for post-compaction history. This ensures old compacted messages are not traversed when building LLM context. - Modify AppendCompaction to create entries with empty ParentID - Update BuildContext to collect kept messages via FirstKeptEntryID - Update GetContextEntryIDs with same logic - Add comprehensive tests for compaction behavior - Add web viewer support for displaying compaction entries	2026-04-08 18:52:44 +03:00
Ed Zynda	b29d7d2166	refactor(acpserver): remove redundant thinking tag parsing Remove dead code now that pkg/kit transparently handles <thinking> and tags at the agent layer. The ACP server no longer needs to: - Track inThinkingTag state across chunks - Parse and split reasoning/text from MessageUpdateEvent chunks - Maintain tag format constants MessageUpdateEvent now contains clean text, and ReasoningDeltaEvent contains structured reasoning - no duplicate filtering needed.	2026-04-08 16:55:53 +03:00
Ed Zynda	3ea0db69ea	fix(ui): wrap user messages to terminal width - Add width parameter to UserBlock and apply lipgloss.Wrap() before passing content to herald Tip alert - Subtract 4 from width to account for alert bar prefix and margin - Pass renderer width from RenderUserMessage to UserBlock - Mirrors the assistant message wrapping added in `e33564c`	2026-04-08 15:15:27 +03:00
Ed Zynda	4304a5e899	feat(ui): change steer keybind to Ctrl+X s leader key chord - Replace single Ctrl+S with Ctrl+X leader prefix followed by "s" - Add leaderKeyActive flag to AppModel for two-key chord state - Ctrl+X sets the leader flag; next keypress completes or cancels chord - Update hint text in input component (adjust width thresholds) - Update /help command output to reflect new keybind	2026-04-08 15:04:48 +03:00
Ed Zynda	4019c1e4f7	fix(ui): remove character limits from all textarea inputs - Main message input: 5000 -> unlimited - Prompt dialog input: 1000 -> unlimited - Tool approval input: 1000 -> unlimited Setting CharLimit to 0 disables the limit in Bubble Tea's textarea.	2026-04-08 14:23:34 +03:00
Ed Zynda	30ad7c1d0b	feat(sdk): persist session messages incrementally per agent step - Add StepMessagesHandler callback to agent's GenerateWithLoopAndStreaming so callers can persist messages as each step completes - Wire onStepMessages in Kit.generate() to call session.AppendMessage for each step's messages immediately on completion - Track PersistedMessageCount on GenerateWithLoopResult so runTurn skips already-persisted messages in post-generation cleanup - Tool calls are always persisted as assistant+tool pairs (never orphaned) - Document concurrency and incremental persistence requirements on the SessionManager interface for custom implementations	2026-04-08 14:15:05 +03:00
Ed Zynda	e33564c569	fix(ui): wrap assistant messages to terminal width - ToMarkdown() received a width param but never used it - Apply lipgloss.Wrap() after herald-md render to break long lines - Preserves ANSI styles/colors through the wrapping pass - Fixes overflow for all markdown paths: assistant messages, tool bodies, and overlay text	2026-04-08 13:34:33 +03:00
Ed Zynda	5ff28445fd	fix(ui): truncate queued and steering message blocks to prevent overflow - Limit each queued/steering block to 3 visible content lines with ellipsis - Account for soft-wrapping when counting visual lines - Truncation is visual only; full text is preserved for scrollback - Add truncateMessageForBlock helper with wrap-aware line counting - Add 7 unit tests covering short, exact, overflow, wrapping, and mixed cases	2026-04-08 13:24:26 +03:00
Ed Zynda	13d177e5d0	fix(extensions): use structured logging that respects log levels Switch from standard log.Printf to charmbracelet/log for extension loading messages. This ensures DEBUG output only appears when explicitly enabled. - Remove unconditional WARN log for failed extension loads - Convert DEBUG loaded extension message to structured log.Debug call	2026-04-08 00:39:21 +03:00
Ed Zynda	3ffc995f27	feat(sdk): add NewTool/NewParallelTool for dependency-free custom tools - Add ToolOutput struct, TextResult/ErrorResult helpers, and ToolCallIDFromContext so SDK consumers can create custom tools without importing charm.land/fantasy - Add NewTool (sequential) and NewParallelTool (concurrent) generic constructors with automatic JSON schema generation from struct tags - Remove dead UpdateUsageFromResponse method and fantasy import from internal/ui/cli.go - Update SDK skill, README, and www/ docs with custom tool examples and corrected hook signatures	2026-04-07 22:05:42 +03:00
Ed Zynda	b2bd016135	fix(tui): redirect log output to file to prevent TUI corruption - Add tea.LogToFile in runInteractiveModeBubbleTea to send stdlib log output to /tmp/kit/kit.log instead of stderr - Replace charmbracelet/log with stdlib log in extensions loader, runner, watcher, prompts loader, and pkg/kit so all log calls go through the redirected stdlib logger - Leave charmbracelet/log in CLI-only commands (install, acp) and acpserver where stderr logging is correct	2026-04-07 21:20:04 +03:00
Ed Zynda	812dedaea2	feat(pkg/kit): add SessionManager interface for custom session backends Add SessionManager interface to allow pluggable session storage backends. This enables users to implement custom session managers for databases, cloud storage, or other persistence mechanisms instead of the default JSONL file-based TreeManager. Changes: - Add SessionManager interface with methods for message storage, tree navigation, compaction, and extension data - Add treeManagerAdapter to wrap existing TreeManager for backward compatibility - Update Kit struct to use SessionManager interface instead of concrete type - Add SessionManager option to Options struct - Update all session-related methods to use interface - Add documentation for custom SessionManager usage The default behavior is preserved - when no SessionManager is provided, Kit automatically uses the TreeManager via the adapter.	2026-04-07 17:41:46 +03:00
Ed Zynda	f65b6737f2	feat(sdk): add SkipConfig and DisableCoreTools options Add two new Options fields for programmatic SDK usage: - SkipConfig: Skip .kit.yml file loading while still using viper defaults and environment variables. Useful for fully programmatic configuration. - DisableCoreTools: Allow creating agents with 0 tools (chat-only mode) or with only custom tools. When true and Tools is empty, no tools are loaded. When combined with custom Tools, only those tools are loaded. Updates documentation in README, pkg/kit/README, skills/kit-sdk/SKILL, and www/pages/sdk/options.	2026-04-07 17:10:58 +03:00