~/.claude/projects/          ┌─ recap ─────────────────────────────────┐
  ┌──────────────────┐         │ task-segmented map: per-task files +     │  ⭐ provably faithful
  │ session_1.jsonl  │────┬───▶│ diffstat, commands, verbatim outcome     │     4 invariants · 1007/1007
  │ session_2.jsonl  │    │    │ + `--audit` (stdlib-only, ~5 ms/session) │     (lossy navigation map)
  │     ...          │    │    └──────────────────────────────────────────┘
  │ session_N.jsonl  │    │
  └──────────────────┘    │    ┌─ substrate ───────────┐   ┌─ compaction ─────┐
                          └───▶│ 5 auto signals + opt.  │──▶│ top-K markdown    │  honest-null:
                               │ label → importance.npz │   │ + budget meta     │  no fidelity edge
                               │ × topic-decay / REM    │   │ (MCP / CLI)       │  over recency/bm25
                               └────────────────────────┘   └──────────────────┘

# 30-second install
pipx install 'weighted-compact[mcp]'

# recap — the provably-faithful consumer; stdlib-only, runs on a bare install
weighted-compact recap --all            # task-segmented map of every session + invariant audit

# compaction substrate (honest-null on fidelity; kept for the substrate-vs-summary result)
weighted-compact bootstrap --full       # extract pairs + build the full signal substrate
weighted-compact mcp-serve              # local stdio MCP for Claude Desktop / IDE clients

→ Docker / Windows install · Operating guide · Bench vs claude-mem · Stability promise · Extension recipe · Pick your door

By the numbers

Every figure here is re-checkable on your own corpus, and each carries its own asterisk in plain sight — the project's stance is that an honest number beats a flattering one.

• 1007 / 1007 sessions pass all four recap faithfulness invariants — coverage · conservation · provenance · determinism (weighted-compact recap --all). This proves the map does not lie about the session — not that it is the optimal summary.
• ~5 ms / session — 584 MB of transcripts mapped in 5.2 s, standard library only (no numpy, no model, no judge in the recap path).
• 0 outbound network calls · 0 MB idle RAM — the first is enforced by the outbound-zero CI workflow, the second because nothing runs between invocations.
• Querying the substrate beats a one-pass LLM summary by ~3.5× on reconstruction fidelity (11.3 % vs 3.2 %, N=62, gemma3 judge). That is the one axis with a measured edge; the importance mixture does not beat cheap baselines at this N, and the comparison table says so.
• recap shrinks a session ~180× — as a lossy navigation map, not a reconstructable archive. For lossless archival, zstd -19 (~3×) wins and this repo points you to it rather than shipping a weaker custom fold.

How it compares

A 30-second product map vs the dominant adjacent tool:

The honest trade: the structural rows above (local, zero-outbound, inspectable, 0 idle RAM, manifesto control) are real and verifiable. The quality row is not a win — on reconstruction-fidelity the six-signal mixture has not been shown to beat cheap baselines like recency or bm25, and neither does hand-curation (see docs/baselines.md). What is a real, exclusive property is manifesto control: your keep/skip labels are honored as a hard selection constraint — a keep-labeled pair is guaranteed to survive compaction (up to budget), a skip-labeled pair is dropped first. Measured on a 16-pair labeled session: 100 % keep-label survival at k ≤ 0.7 (vs recency baseline 62 %). That is a deterministic control guarantee, not a compression-quality claim (proven by construction in tests/test_manifesto.py; default-on in the compact_session MCP tool, meta.manifesto reports what it honored). claude-mem is hook-installed in seconds and feels magic; weighted-compact is a transparent substrate you own, steer with a manifesto, and query with intent. Pick on transparency / locality / control, not on compression quality — see docs/bench-vs-claude-mem.md.

The substrate is the artifact

~/.claude/projects/ already contains the record of every correction you pushed back on, every flag you restated, every constraint the model lost track of. weighted-compact reads those files once, parses them into per-pair objects (correction text, premise text, span tiers, session anchors), and decorates each pair with six signals: density features, span coverage (four tiers: keep / maybe / skip / think), and one optional human label.

The decorated substrate lives at $XDG_DATA_HOME/weighted-compact/ — gitignored, never uploaded. It is the artifact. Compaction is the first reader; other consumers read the same files.

Five of the six signals run without any human input. The sixth — label — is an optional power-tier, not a requirement: the published ablation puts its 95 % paired CI [−0.004, +0.109] crossing zero on the lower bound, with 67 % of paired runs showing zero difference. The substrate stands on the five automatic signals (density + four span tiers); the labeler at :18890/ is opt-in for users who want to add an explicit human judgement track.

A nightly REM pass (weighted-compact rem-pass, default 04:00 via the bundled systemd-user timer) lays a wall-clock half-life multiplier on top: yesterday × 0.91, week ago × 0.50, month ago × 0.05. Independent of the six-signal mixture — content signals stay stable, time refreshes every day. See docs/rem-decay.md.

Consumers reading this substrate today