Code Review Gate skill

Code Review

Check for code defects, test quality, and change impact, and confirm that the issues found are closed.

Resources and Execution Location

• references/, scripts/, and assets/ are relative to the directory containing the SKILL.md read for this run.
• Run shell commands from the reviewed project root; docs/work/, code paths, and project rules all belong to the reviewed project.
• CODE_REVIEW_SKILL_DIR below is the absolute path of the skill installation directory. Set it on every shell invocation, or replace it directly with the actual absolute path; do not assume variables persist across different shell invocations.
• Scripts require basic commands such as Bash 3.2+, Git, awk, grep, and sed. Invoke them via bash; no executable bit is needed.
• Report parsing requires Python 3.9+ and PyYAML; python is invoked by default, and CODE_REVIEW_PYTHON can specify the interpreter's absolute path. For installation, see the release repository README; the in-repo entry point is scripts/install.py.

Scope

• Review functional, bug-fix, refactoring, or configuration changes that affect code behavior.
• Pure documentation, formatting, or typo changes that do not affect code behavior may be skipped.
• Static review is still possible when tests fail or have not been run; the report must state the test status and must not claim that merge conditions are met.

Inputs

Input	Required	Description
git repository + diffable changes	Yes	Specify whether to review uncommitted changes or a committed base/head range
Acceptance criteria	No	When provided, check them off one by one under "Optional Wrap-up"
Coverage data / command	No	When provided, used for the optional measurement in test-coverage; without it, static quality checks on the relevant test code still run
Rule pack	No	Defaults to the skill's built-in references/rules/; can be overridden with CODE_REVIEW_RULES_DIR
Review identifier	No	{slug}, defaults to <date>-<topic>

The artifact root {output_root} defaults to docs/work; override it with project .code-review/config.json output_dir or CODE_REVIEW_OUTPUT_DIR. This run's artifacts are written to {output_root}/active/{slug}/.

Review Process

Check items are not hardcoded in this file; they are driven by the references/probes.yaml registry. Probe implementation details are in references/probes/<probe-name>.md; this file covers main workflow orchestration and shared probe execution boundaries.

Execution boundary: static review by default. For coverage checks, prefer reusing an existing report; when measurement is needed, coverage commands may be run within what this round's task allows. Other checks remain read-only evidence. Do not modify the reviewed source code during review. Test and CI output are review evidence; all tests green does not mean the behavior is correct.

1. Determine the review scope:

   At the start, the main executor runs the environment check once. Read tool paths, versions, and missing items from its JSON and hand off usable commands to probes as needed:

   "${CODE_REVIEW_PYTHON:-python}" -X utf8 "$CODE_REVIEW_SKILL_DIR/scripts/check-environment.py"
   

   Resolve failed required checks first; add --bash /path/to/bash to select Bash explicitly. If rg is missing, use the returned fallback and read untracked files separately. Results go to stdout and need no artifact file; tool availability applies to the environment running the command.

   Choose a mode; when unspecified, review uncommitted changes by default. The base/head below are recorded as concrete commit IDs.

   • Uncommitted changes (worktree): base is the current HEAD. Use git diff <base> -- to collect staged and unstaged changes; use git ls-files --others --exclude-standard -z to collect untracked files, and review their full contents as newly added code.
   • Committed range (commits): use the user-specified base/head, and collect the diff with git diff <base> <head> --. When head is omitted, use the current HEAD and review only that commit range.

   Read the corresponding source:

   • In worktree mode, read the working tree files.
   • In commits mode, use git show <head>:<path> to read the target version, and read base when an older version is needed. File scans use only on-disk files consistent with the target version.

   Record and hand off: save the mode, base, target (working tree or head), changed-file list, and diff, for use by all probes. Use NUL separators when processing the file list programmatically, and pass each path as a quoted argument.

   After collecting scope, initialize a new run before dispatching:

   bash "$CODE_REVIEW_SKILL_DIR/scripts/collect-metrics" init {slug} --mode worktree
   # or: init {slug} --mode commits --base {base} --head {head}
   

   The returned JSON gives review_dir, output_dir, line_target, branch_target, and snapshot_id. With --mode, init also writes review-snapshot.json, which pins the reviewed source (worktree file hashes or the fixed base/head commits). New runs must pass --mode; omitting it keeps the legacy behavior. Existing active directories, archived runs, or event history with the same slug are rejected. Use a unique slug for a new review; explicitly continuing the same run reuses its directory without init. Never dispatch two runs writing the same directory. Pass the actual directory and effective targets to all probes, overriding the registry's coverage defaults. Init creates the report template. After a fix or a stale-review result, run snapshot {slug} to update the snapshot, re-run the affected probes, re-render the report, and check the gate again. Source inspection is read-only; the workflow writes reports, probe JSON, review-snapshot.json, events, and archive metrics.

2. Read the registry and determine the probe list: Read references/probes.yaml and decide by requires:

   • Specified but missing / unreadable → error
   • Optional input not provided → skipped, stating what is missing
   • Available → execute

3. Run probes in parallel:

   Dispatch: the main executor dispatches an independent agent per probe according to the registry, providing the review scope, diff, project root, skill path, that probe's inputs and params, the path to references/probes/common.md, and the "Execution boundary" above. Require each agent to read common.md before its probe-specific document. Also pass any provided requirements, acceptance criteria, and change context as text or file paths, and ask each probe to read relevant material. Note missing inputs without inventing them. If dependency source or contract material is already available, pass its path, version, and origin for on-demand reuse; do not pre-download all dependencies.

   The agent reads the instructions pointed to by the registry entry's file and references/output-schema.md, and executes according to the parameters. Run in batches when concurrent slots are insufficient; if independent agents are unavailable, run serially and record the limitation.

   Shared probe constraints: defined once in references/probes/common.md. Include its path in every dispatch; do not repeat or paraphrase the rules per probe.

   Handoff: every probe must have JSON for this run. Record skip or error reasons according to the output contract; on execution errors, preserve findings already made and let the other probes continue. If an agent fails to start or returns no valid result, the main executor records error and the reason without reusing old results.

   test-coverage hands off the report path, target version, numerator/denominator, and percentage for valid coverage via its return message, and the main executor reports them; --line accepts only diff line coverage:

   bash "$CODE_REVIEW_SKILL_DIR/scripts/collect-metrics" coverage {slug} --line {diff-line-coverage}
   

   Add --branch {branch-coverage} when a branch value exists, or report only that item. Omit unmeasured or inapplicable metrics without filling in 0; do not call it when neither value is valid. A single-item report updates only that item, and the script does not verify the statistical basis.

   Aggregation: after all agents finish, the main executor runs the synchronization command. The script reads required from the registry and computes counts at each level from the probe JSON; do not rewrite raw results or hand-fill counts. Do not deduplicate across probes yet; count by original finding ID, which may include duplicate records of the same root cause:

   bash "$CODE_REVIEW_SKILL_DIR/scripts/collect-metrics" sync {slug} --probes
   

   This step invalidates the previous batch's reconciliation state, and reconciliation is not recorded yet.

4. Reconciliation completeness check: Derive the final counts automatically from the probe JSON:

   bash "$CODE_REVIEW_SKILL_DIR/scripts/collect-metrics" sync {slug}
   

   required only controls whether that probe's failed/error execution status directly blocks; it does not change the finding closure requirement. High findings from any probe enter reconciliation and still block merge until closed; medium/low are recorded in the report and excluded from the reconciliation total:

   RECONCILE_TOTAL   = total number of high findings
   RECONCILE_DONE    = number of those whose status is reconciled or false-positive
   RECONCILE_PENDING = TOTAL - DONE
   

   Run it even when there are no high findings, explicitly recording the zero result; do not substitute old counts or hand-filled numbers. Fix format errors first; if records are missing, IDs are duplicated, or statuses conflict, synchronization fails, no counts are written, and the old result must not be used to pass. When there are unresolved issues (RECONCILE_PENDING > 0), still deliver the report this round and list the blocking items; do not proceed toward merge. After follow-up fix tasks complete, re-review the affected parts; see execution.max_retry in references/probes.yaml for the re-dispatch limit.

5. Compile the report:

   Fill in the review scope, explanation, fix suggestions, and limitations per the template; do not embed raw JSON in the body; when acceptance criteria are provided, complete the item-by-item check-off first.

   The script displays unverified_items as "Pending confirmation" in Findings without including them in severity counts; original records retain their IDs, evidence, and counts; when showing the number of distinct issues, group them by the same root cause and consequence and list the corresponding IDs, without raising severity due to duplication or substituting the displayed count for probe or reconciliation counts.

   Run this command to generate the report's facts section from the JSON, validate the display, and obtain the final answer summary; it stops immediately if any step fails:

   bash "$CODE_REVIEW_SKILL_DIR/scripts/collect-metrics" finalize {slug}
   

   The scripts update only the code-review:probes / gate marker regions under Findings and Review Conclusion, preserving other body text and raw JSON. Rendering validates before an atomic update and can be repeated; it stops when markers are missing or duplicated. Validation covers IDs, locations, evidence, severity, status, and counts.

   summary validates the report first and outputs the machine summary only when it is consistent. The high/medium/low counts, finding IDs, and blocking conclusion in the final answer must follow the summary; do not add unrecorded issues or omit recorded high findings. Deliver the report, blocking items, and unverified content to the user; you may add explanations and suggestions, but must not rewrite the automatic regions or overturn known blocking facts.

   "No recorded blocking items" does not mean acceptance, coverage, tests, or CI have passed. Both gate-pass {slug} code-review and archive with review records validate the report first, then synchronize counts, and do not automatically fix a rewritten display.

   verify-report checks only that the report regions match the probe JSON; it does not check source freshness. gate-pass {slug} code-review first re-computes review-snapshot.json. If the reviewed source changed, it returns stale-review (exit 3) without writing a gate event.

Any of the following conditions blocks merge. This round's report lists the blocking items; the table below gives the follow-up handling requirements:

Blocking condition	Follow-up action
A required probe is failed / error (PROBE_REQUIRED_FAILED > 0)	Handle the issues found or the execution error, then re-run the corresponding probe
The reviewed source no longer matches review-snapshot.json (stale-review)	Update the snapshot and re-review per step 1
A high finding has not completed reconciliation (RECONCILE_PENDING > 0)	Handle per step 4, and re-dispatch the affected probes after fixing
Reconciliation was never reported (RECONCILE_REPORTED=0)	Complete step 4; run the final synchronization even when there are no high findings
Coverage data was provided and is below baseline (below project line_target; default 85%)	List the coverage gaps, add tests, and re-review
Acceptance criteria were provided and not all pass, or the criteria themselves are ambiguous	List the failing items; clarify ambiguity first, and do not self-check them as passing
A high finding remains in wontfix	Complete handling per the output contract; "won't fix" cannot offset a pending item

See section 4 of references/output-schema.md for how execution status and input errors are determined.

Script validation verifies consistency between report records and counts; it cannot prove the checks were sufficient.

Output Contract

• Main report: {output_root}/active/{slug}/code-review.md, generated per the sections and filling requirements in assets/code-review.md.
• Machine records: {output_root}/active/{slug}/probes/<probe-name>.json, format per references/output-schema.md; the human report's facts section is derived from them.
• Review snapshot: {output_root}/active/{slug}/review-snapshot.json, written by init --mode; gate-pass code-review uses it to reject stale evidence.

Historical records must be explicitly migrated to standalone JSON; do not infer from free text or auto-fill zeros, and do not read old embedded blocks at the same time.

Optional Wrap-up

The following items are done conditionally, not as mandatory steps each round:

• Acceptance: when acceptance criteria are provided, check them off one by one before the final conclusion; otherwise skip and say so.
• lessons: when a lessons/ directory exists and something that actually happened this round is worth reusing, record it with the specific problem, cause, and handling:
  • Pitfalls hit during implementation → lessons/pitfalls.md
  • Cases where AI output was corrected → lessons/bad-cases.md
  • New architectural decisions → lessons/arch-decisions.md
• Archive: when archiving is needed, move {output_root}/active/{slug}/ to {output_root}/archive/{YYYY}/.