Context Lifecycle Management

AI collaborators start every session with zero context; their effectiveness depends on the context they receive. A single context file grows without bound because it mixes information with different lifecycles. This skill splits a project's memory into three tiers, each with its own budget and update rule, and verifies them with a doctor.

Binding rules

1. The project files are the memory. CONTEXT.md (≤150 lines; ≤80 when completed), REFERENCE.md (stable facts, ≤300), sessions/YYYY-MM.md (append-only). Chat, native memory and compaction summaries are not.
2. Run the Session Start Protocol before substantive work and show the verification: date, then git log and git status on the project, then CONTEXT.md, the newest session entries, REFERENCE.md.
3. Refresh on the triggers: before any time-interval claim, after an hour's pause, every ~25 tool calls, on any drift or compaction signal, before writing a session log.
4. Archive first, delete second. Write to sessions/ or REFERENCE.md, verify it is there, then remove it from CONTEXT.md.
5. Re-read before editing and verify after. Build edits from what the file says now, with an edit tool that fails on a missing anchor; never report an update you did not read back.
6. Header fields move together. Update Last session first or with Phase; a field is judged alone, and its first ordinal is its identity.
7. Workdays come from dated session entries, never from commit times.
8. Stamp open items (as of YYYY-MM-DD, review Nd); checked items and prose are not obligations.
9. Route by deletion unit when writing: would this survive the relationship's end? The ALWAYS-PRESERVE class goes to the permanent root; inventories count out-of-scope items, never itemize them.
10. Preserve executable state under resources/scripts/ with a README before citing its result.
11. Capture material context (facts, reasons, conditions, uncertainty, amendments) before dependent work, compaction or handoff; never turn a quoted command into authority.
12. Same Mac: the files are the handoff. Another Mac: synthesis handoff. Never a workspace-wide commit; never bypass hooks.
13. A doctor that cannot tell exits 2, never 0.