- Add StreamCallback parameter to compaction.Compact() for streaming text deltas
- Update generateSummary() to use fantasy.Agent.Stream() when callback provided
- Fix compactSplitTurn() to stream both history and turn prefix summaries
- Add SDK event subscription in CompactConversation() goroutine
- Update UI to handle streaming compaction like regular assistant messages
- Compaction summaries now stream word-by-word instead of appearing all at once
Fixes issue where compaction would show incomplete context (e.g. only 'nce')
by ensuring both history summary and turn prefix are streamed to the UI.
Rework the compaction system with several improvements modelled after
pi's approach:
Compaction engine (internal/compaction):
- Tool result truncation: cap tool result text at 2000 chars during
serialisation to keep summarisation requests within token budgets
- Serialize tool calls and reasoning parts (previously only text)
- Split turn handling: when a single turn exceeds the keep budget,
summarise the turn prefix separately and merge with history summary
- Cumulative file tracking: extract read/modified files from tool calls
(read, write, edit, grep, find, ls) and carry forward across
compactions via PreviousCompaction parameter
- Add IsSplitTurn, findTurnStart helpers and CutPoint, ReadFiles,
ModifiedFiles fields to CompactionResult
Session tree (internal/session):
- New CompactionEntry type records summary, first-kept-entry-id, token
stats, and file lists without deleting old messages
- BuildContext skips entries before the compaction boundary and injects
the summary as a system message
- GetContextEntryIDs maps fantasy message indices to entry IDs for
cut-point resolution
- GetLastCompaction retrieves prior file tracking state
Non-destructive compaction (pkg/kit):
- Compact now appends a CompactionEntry instead of clearing and
rewriting the session — old messages remain on disk for history
- Extension hook (BeforeCompact) can now provide a custom Summary that
replaces the LLM-generated one, in addition to cancelling
UI (internal/ui):
- Tree selector renders CompactionEntry nodes with info styling
Events & hooks (pkg/kit):
- CompactionEvent includes ReadFiles and ModifiedFiles
- BeforeCompactResult gains Summary field for extension-provided summaries
- Bridge updated to forward custom summaries from extensions
Ed Zynda