loop-gate

Mechanical enforcement of static safety policy — the code behind docs/safety.md's Path Denylist and Auto-Merge Policy, and LOOP.md's "No auto-merge on main except trivial dependency patches" / "Denylist... without human review" rules. Nothing evaluated a proposed change against that prose before; loop-gate does.

Deliberately has no knowledge of run history. Stagnation, repeated failures, and token/daily budgets already belong to loop-context's circuit breaker — loop-gate only looks at what is being proposed (which paths, what action type), not how the run has behaved so far. Chain the two:

loop-context --check --ledger run.json ...            || exit 2   # run-history based
loop-gate check --action auto-merge --paths a.ts,b.ts  || exit 2   # policy based
do-the-merge

Install & Run

npx @cobusgreyling/loop-gate check --action auto-merge --paths docs/guide.md

From this repo:

cd tools/loop-gate
npm install
npm test

Usage

loop-gate check --action <commit|merge|auto-merge> --paths <f1,f2,...> [--gate-file gate.yaml] [--json]

| Flag | Default | Meaning | |------|---------|---------| | --action <commit\|merge\|auto-merge> | required | What the loop is about to do | | --paths <f1,f2,...> | required | Comma-separated changed file paths | | --gate-file <path> | gate.yaml (cwd) | Policy file to evaluate against | | --json | off | Machine-readable decision output |

Exit codes: 0 allowed · 2 escalate · 1 error (bad flags, missing/invalid config).

Policy file

gate.yaml is the machine-readable twin of docs/safety.md — see templates/gate.yaml.template to scaffold your own, or this repo's own dogfood gate.yaml:

version: 1
denylist:
  - ".env"
  - "**/secrets/**"
  - "auth/**"
maxFiles: 10
autoMergeAllowlist:
  - "docs/**"
  - "**/*.md"

Checked in order (first match wins, same "most specific trigger first" convention loop-context's circuit breaker uses):

1. denylist — any changed path matching a glob here escalates, regardless of --action.
2. maxFiles — more changed paths than this escalates (matches docs/safety.md's "Changes touching >N files" human gate).
3. autoMergeAllowlist — only checked when --action auto-merge; every changed path must match one of these globs, or it escalates.

Glob matching is via minimatch (the same semantics .gitignore-style globs use — ** matches across path segments).

What this does not do

• Does not read a run ledger, and never will — that keeps it decoupled from loop-context at the source level, the same way loop-worktree and loop-context stay independent while still being paired by convention in a control script.
• Does not produce its own escalation summary format — fold its JSON decision into whatever your control script already assembles from loop-context --inject when escalating to a human.
• Does not enforce anything by itself — like loop-worktree's locks, this is advisory: a control script that skips calling loop-gate is not physically blocked. The mechanism is only as good as the scripts that call it.

See docs/safety.md for the policy this codifies, and docs/primitives.md for where safety gates fit in the Five Building Blocks + Memory model.