Session Summary Compaction
Episodic memory as generated summaries: session transcripts compress into what-happened digests at session end or context-limit compaction, so continuity survives the context window.
When to use
Long-running projects where sessions exceed the context window and the next session needs to know what the last one did and decided.
Specification
| Memory type | episodic |
|---|---|
| Storage | generated summaries of session transcripts, stored per session or rolled into a running digest |
| Retrieval | loaded at session start or on explicit recall |
| Update method | hook-written at session end or context-limit compaction |
| Decay / staleness handling | Older summaries compress further or drop; recency-weighted retention is the standard policy. |
| Risk level / maturity | medium / established |
Privacy and safety
Summaries inherit anything sensitive said in session; redaction must happen at write time, not read time.
Failure modes
- Lossy summarization drops the one detail that mattered
- Summaries state intentions as outcomes
- Digest drift after many compression generations
Assessment
Necessary infrastructure rather than a choice: every long-running agent compacts eventually. The failure to design for is intentions-recorded-as-outcomes, which poisons every later session with false history.
Evaluation method: Context-reconstruction time after a cold start; task continuation accuracy across a forced compaction.