pr-to-spec

pr-to-spec

Overview

Turn observed code changes into a versioned JSON spec and compare them with a declared intent. Lead with the outcome and supporting signals, risks, contracts, and policy evidence; never treat a nonzero gate exit as an ordinary CLI failure.

Prerequisites

Run inside the Git repository being analyzed with Node.js 20+ and pr-to-spec on PATH.
Fetch the intended base ref before branch comparison if the local ref may be stale.
For remote PR analysis, provide GITHUB_TOKEN through the environment. Prefer a fine-grained token with pull-request read access; do not pass tokens on the command line or print them.
Treat .pr-to-spec/intent.yaml, contracts.yaml, and policy.yaml as project governance state. Review changes before committing them.

Instructions

Step 1: Declare intent before editing

Quote globs so the shell does not expand them:

pr-to-spec intent set \
  --goal "Add rate limiting to the API" \
  --scope "src/middleware/**" \
  --forbid "src/db/**" \
  --max-risk medium \
  --json
pr-to-spec intent show --json

Add --type or --size-budget when they express a real acceptance boundary. Do not broaden intent after a drift result merely to make the gate pass.

Step 2: Select one local comparison

Use one comparison mode and request JSON for deterministic agent parsing:

pr-to-spec scan --branch main --json
pr-to-spec scan --staged --json
pr-to-spec scan --diff 3 --json

--staged takes precedence, then --diff; otherwise the CLI compares the current branch with --branch or main. A scan can exit 2 when high-risk changes are found even though it produced a valid spec.

For a GitHub pull request, use the root command:

pr-to-spec --repo OWNER/REPO --pr 42 --json

Set the token in the calling environment without echoing it.

Step 3: Check completed work

Run the same comparison boundary used for the scan:

pr-to-spec check --branch main --json

Expected result: a versioned envelope whose exit code distinguishes clean, high-risk, drift, policy failure, and runtime error states.

If no intent exists, check falls back to scan behavior and returns 0 or 2. With intent, it evaluates drift, verification contracts, and any policy gate. Read the JSON status, signals, gate_result, and contracts fields before deciding whether work may continue.

Step 4: Respond to the gate

0: clean for the evaluated boundary.
2: valid result with high-risk changes; review risk flags.
3: drift or a blocking contract violation; fix the change or deliberately revise intent with an explicit explanation.
4: policy gate failed; satisfy its blocking checks.
1: invocation, Git, configuration, or runtime error; repair and rerun.

Never collapse codes 2–4 into a generic failure because each requires a different response.

Output

JSON output uses the versioned agent-protocol envelope:

{
  "version": 1,
  "command": "check",
  "status": "drift_detected",
  "exit_code": 3,
  "signals": [],
  "spec": {},
  "intent": {}
}

Report the comparison boundary, exit code and meaning, changed-file summary, highest risk, each drift signal, contract and gate results, and the next safe action. Preserve the JSON with review evidence when it gates a release.

Error Handling

Missing base ref: fetch or choose an existing ref; verify with git branch -a.
No changes: confirm the selected branch, staged set, or commit count.
No intent: declare one for drift checking, or state that check used scan-only behavior.
Exit 2, 3, or 4: parse the emitted envelope before remediation.
Remote authentication failure: validate repository access and token scope without logging the token.
Malformed governance YAML: repair the named .pr-to-spec file and rerun.

Examples

pr-to-spec intent set --goal "Refactor cache keys" \
  --scope "src/cache/**" --forbid "src/auth/**" --max-risk low --json
pr-to-spec check --branch main --json

pr-to-spec scan --staged --field intent.change_type --stdout

Expected result: only the inferred change type for the staged diff.

About this skill