cc-compact

Run git rev-parse HEAD to get the current commit SHA (the full 40-char hash — NOT --short, whose abbreviation length auto-scales with repo size and is unstable across growth). Lowercase and trim it; if it does not match /^[0-9a-f]{7,40}$/, or the command exits non-zero (non-git workspace, no commits, git absent, or permission-denied), use "0000000". Wrap the call with shell timeout only when command -v timeout (or gtimeout) succeeds; otherwise run it unwrapped. This same value is sys.c and the sessions / snapshots git-hash key.

Determine sys.s: take the active specification file path from this phase's context, split on / and \, keep the last segment, strip a trailing .md extension, truncate to 200 characters. If no active spec file exists, use "none".

Collect from the current conversation context:

• Phase (sys.ph): spec | plan | impl | rev, the phase that just completed
• Decisions (mem.d): finalized decisions this phase, max 10 elements, each ≤300 chars (JSON-serialized length)
• Pending (ops.n): next immediate step(s), max 3 elements, each ≤200 chars
• Files Touched (ops.f): each entry <relpath>:C|M|D (uppercase only); replace any backslash in the path with /; if the path contains a literal :, percent-encode it as %3A before appending the suffix; max 20 elements, each ≤300 chars
• Constraints (mem.x): hard constraints next phase must respect, max 5 elements, each ≤200 chars

For all four array fields: filter out empty/whitespace-only strings, deduplicate by exact case-sensitive string equality (first occurrence wins), then truncate each surviving element to its per-element cap (Unicode-safe: Array.from(str).slice(0, cap).join('')), then if the array still exceeds its cap, drop from the head (oldest first) until it fits. Empty arrays are valid and must still be serialized (never omitted).

Serialize by piping a flat JSON object {ph, c, s, n, f, d, x} (no pr) on stdin to node .claude/scripts/snap-build.mjs; its stdout is the canonical single-line v1 SNAP JSON. snap-build performs all array normalization (filter/dedup/per-element cap/head-drop) and the 4096-char size trim internally — do not pre-serialize. If snap-build exits non-zero (malformed field object), report the error and stop; do not write the handoff file, do not run the DB tail, do not print the compact prompt.

Write the single JSON line, followed by exactly one trailing newline, to .claude/memory/session-snapshot.json.

If .claude/memory/session-snapshot.md exists, delete it as part of this write.

Idempotently append .claude/memory/session-snapshot.json to the project's .gitignore: read the file; if any line, after stripping leading/trailing whitespace, exactly equals .claude/memory/session-snapshot.json, skip the append. Otherwise, check whether the last byte of .gitignore is a newline; if not, prepend a newline before the appended entry. If .gitignore cannot be read or written (permission or lock error), log a non-fatal warning to stderr and continue; do not block the snapshot write.

If writing the snapshot fails (e.g., missing .claude/memory/ directory), report the error and stop. Do NOT output the compact prompt.

Once the snapshot is written successfully, output exactly:

Snapshot written. Run /compact now to clear history.

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Fail-open DB tail (best-effort, synchronous)

After the handoff file is written and the compact prompt is ready — and only if the authoritative write succeeded — run this synchronous, fail-open tail. Any failure here is non-fatal: never revert the handoff file, never suppress the compact prompt.

1. Ensure .conductor/ exists (mkdir -p .conductor, best-effort). If that fails, skip the tail entirely.
2. Resolve the session id: id="$(node .claude/scripts/session-id.mjs 2>>.conductor/last-write.log)".
3. Upsert the session row (Node-flag probe applies — same as the cc-implement Step 6 hook: no-flag-first, else --experimental-sqlite --no-warnings, else skip):