Presence-only guard over shared/method-spec.md, mirroring the ingest-spec
guard: file presence, structure markers (##1–##12, Step 1–8, MUST),
framework-neutrality (same forbidden-toolkit list), and §12 coverage of
all 31 consumed contract fields — scoped to the §12 block in backticked
form so a pure table-row removal detaches (precision lesson from the
ingest guard's detach spot-check). Red-proofs (a: missing file, b:
injected toolkit name, c: removed §12 field) run parametrized against a
mutated copy in tmp_path, never against shared/.
Full gate green: 347 passed, ruff + format + mypy clean; no src changes.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>