2026-03-01T08-48-42_auto_memory/memories.db-wal, memory/2026-03-01-session-

memory/2026-03-01-session-continuity-protocol-feature-planning.md

@@ -0,0 +1,42 @@
+# 2026-03-01 Session Notes
+
+## Session Continuity Protocol Feature Planning
+
+Nicholai designed a comprehensive feature to help Signet agents survive context window limits by capturing session state checkpoints before compaction. The system uses two data channels: passive accumulation (automatic observation of queries and /remember calls) and agent-initiated digests (via MCP tool, Phase 2).
+
+### Architecture Overview
+
+The implementation spans three phases:
+- **Phase 1**: schema, sessionKey plumbing, passive checkpoints, recovery injection, API endpoints
+- **Phase 2**: MCP session_digest tool and agent instruction updates  
+- **Phase 3**: pre-compaction enrichment, pruning tuning, scorer integration
+
+Checkpoints are stored in a new `session_checkpoints` table with normalized project paths (via realpath) for reliable matching across symlinks. The table uses UUIDs instead of sequences to avoid race conditions on concurrent writes.
+
+### Key Decisions
+
+- **Separate table from memories**: checkpoints have different lifecycle (hours vs weeks), query patterns, and retention. Mixing would pollute the scoring/decay pipeline.
+- **Dropped sequence column**: avoids race conditions; ordering by `created_at DESC` instead.
+- **Added project_normalized**: resolves symlink aliases for reliable cross-session matching.
+- **Buffered checkpoint writes**: 2-3 second debounce to avoid blocking hot paths on user-prompt-submit.
+- **Pre-reserved budget for recovery**: 2000-char section injected at session-start before memory injection to guarantee space.
+
+### Implementation Scope
+
+Nine implementation steps identified:
+1. SessionKey plumbing in CLI hooks to extract and forward `session_id` from Claude Code
+2. Migration 016 for session_checkpoints table and indexes
+3. New continuity-state module for per-session accumulation tracking
+4. New session-checkpoints module for checkpoint CRUD operations
+5. Buffered flush queue (setTimeout-based)
+6. Hook integration (session-start, user-prompt-submit, remember, session-end, pre-compaction)
+7. CLI parsing updates
+8. Redaction of agent-initiated digests before storage
+9. Configuration schema under PipelineV2Config
+
+### Open Threads
+
+- Phase 2 and 3 implementation deferred
+- MCP session_digest tool design pending
+- Pruning policy and retention day thresholds TBD
+- Scorer integration with checkpoint relevance ranking pending