/refactor-extract

Substance lives in markdowns/protocols/refactor-extraction.md.

Steps:

1. Discriminate kickoff vs iteration per auto-trigger-discriminator.md. If iteration / polish / investigation, exit silently. Explicit /refactor-extract invocation bypasses; mechanical signals (duplication / file-size) and authoring-time near-match are kickoff by definition.
2. Detect. Cite the mechanical signal (duplication cluster file:line ↔ file:line from jscpd or similar, file-size LOC warn or fail). No mechanical signal, no advance — the duplication policy is the gate.
3. Decide. Produce a structured rationale (the 4+ duplicates that justify extraction, the proposed helper signature, the ≥70% applicability check, the FCPSS coverage). Run cross-vendor plan-review against the rationale markdown via scripts/cross-vendor-review.sh. Iterate to a clean pass (Tier 1: no decline path).
4. Execute. Write the helper / land the split + test pin first. Migrate callers one at a time with the suite green between each. Verify the signal cleared (re-run the duplication checker, re-count file size). No half-migration.
5. Prevent regression. The test pin is the durable guard; the duplication checker + file-size hook keep watching the surface; the duplication policy in root AGENTS.md Definition of Done is the steady-state authoring rule.

Execution diff goes through standard cross-vendor code review at PR time per cross-vendor-review.md. Supervision pattern per supervision.md.