### Mode: grounding

<!-- opt-in-capability: none — an on-demand assembler that leaves no persistent state the advisor could observe -->

The **grounded-review facts assembler** (AD-038) — an ungrounded `agy` review GUESSES, and while the grounding contract is mechanized (`agy-review code --facts @f`), populating the facts file was a manual chore. This mode emits the **mechanical** facts sources of a payload (constraints / autonomy / plan / ledger digest); the orchestrator still owns any judgment-bearing additions — delivered via `--extra`, never a shell append onto the emitted file (corpus #88/#95). **Catalogued honestly as a WRITER** — `--out <path>` writes one file — with the invariant: `--out` accepts **only system-temp destinations outside the repo ($TMPDIR / /tmp — rewritable scratch) or a FRESH gitignored in-repo path (create-only, exclusive write)** and REFUSES everything else: a tracked path, an in-repo not-ignored path (a new untracked file would itself move the review fingerprint the facts are about to ground), an EXISTING in-repo file even when gitignored (the `.env` clobber class — this writer is bridge-tier auto-allowable), any other outside-repo destination, and symlink/non-regular leaves; **stdout is the default**. It never commits and never runs a subscription CLI.

Run `node ${CLAUDE_SKILL_DIR}/tools/grounding.mjs [--constraints] [--autonomy] [--plan <path>] [--extra <text|@file>]... [--reserve-bytes <n>] [--out <path>]`:

1. **`--constraints`** — slice the root `AGENTS.md` **Hard Constraints** section, verbatim and whole (exactly ONE matching heading; zero or several is a loud STOP, never a guess — the marker-slot discipline).
2. **`--autonomy`** (AD-044 Plan 3) — append the COMPUTED effective autonomy policy: the shared resolver (`resolveAutonomy`) over the **git-top** `docs/ai/autonomy.json` renders every red-line + per-activity level with a stated source line. An ABSENT file is exit 0 — the computed defaults ARE the effective policy (unlike `velocity-profile --autonomy`, which writes settings and refuses an undeclared policy); a malformed/unreadable policy fails CLOSED (exit 1). Informational for the reviewing backend — enforcement stays the OS sandbox + the orchestrator. Rides between the constraints and the plan sections.
3. **`--plan <path>`** — extract the plan's three canon sections, verbatim + whole: `## Goal and boundary`, `## Module ledger`, `## Verification` (the engine `planning.md` literal headings; each REQUIRED — a missing or DUPLICATE heading is always a STOP).
4. **`--extra <text|@file>`** (corpus #88/#95 — the fourth firing of the same pre-dispatch append step) — append orchestrator-supplied facts byte-VERBATIM after the mechanical sections (repeatable, argv order; the `agy-review --facts` convention: literal text, or `@path` read whole through a race-free descriptor). An `@file` must resolve inside the PROVEN git work tree (rev-parse success — no cwd fallback; the git dir itself is refused) or the system temp surface — anything else refuses loudly (the exfil class: this tool is bridge-tier auto-allowable), as does a missing, EMPTY, or non-regular file (a FIFO cannot block the read). The merge happens INSIDE the tool, so the promptless lane is the invocation itself.
5. **Byte budget** — the output honors the same `AGY_MAX_PROMPT_BYTES` contract the agy wrapper enforces (override may only tighten; the OS argv ceiling is rejected), MINUS **`--reserve-bytes <n>`** — the artifact share the caller expects `agy-review` to add around these facts. Overflow is trimmed tail-first with a loud in-band marker + stderr report — never a silent cut.
6. Feed the result to the wrapper: `agy-review code --facts @<out>`. The `procedures` advisor renders this invocation as a concrete pre-step whenever the resolved review dispatch includes agy — populated with the in-flight plan path when exactly one plan is in flight.

**Invariants:** writer (writes at most the ONE `--out` scratch file — system-temp, or a fresh gitignored in-repo path, exclusive-create) · never commits · never runs a subscription CLI · verbatim slices + verbatim extras (assembly is mechanical; facts judgment stays with the orchestrator — `--extra` carries it, the tool never edits it).