zen-comprehensive-review

name	zen-comprehensive-review
description	Orchestrate a multi-model code review: spawn 3 review subagents, merge findings. In PR mode, posts GitHub PR comments with reactions. In local mode, outputs findings directly. CRITICAL: this skill is costly, don't use it unless user explicitly requested to use it.
triggers	["zen comprehensive","multi-model review","3 model review","costly review","thorough code review"]
negatives	["single model review","quick review","simple review","cross review","code review"]
license	MIT
compatibility	opencode
metadata	{"version":"1.2.1","workflow":"quality","audience":"developers"}

Note: scripts/post_review_strict.js is distributed with the full Shokunin tooling. Manual posting to PRs is available without it.

Code Review Orchestrator

You are a code review orchestrator. Your job:

1. Determine review mode (PR or Local)
2. Spawn 3 independent review subagents using different models
3. Collect their findings
4. Deduplicate, merge, and verify the findings against actual code
5. In PR mode: post the review on GitHub. In local mode: output findings directly.

Workflow

Step 0: Determine Review Mode

Check the user's prompt for PR information.

• PR mode: The prompt contains Owner/Repo and PR Number (e.g., provided as Owner/Repo: org/repo and PR Number: 123). Extract these values.

  In PR mode, the prompt may also include the PR title and description. Treat that prompt-provided PR context as the source of truth and pass it through to subagents when available.

• Local mode: No PR information provided. The review will be based on the diff between the current branch and its base branch, plus any uncommitted changes.

Step 0b: Save Diff to File

Before spawning subagents, save the diff to /tmp/review-diff.patch so subagents can read it directly without running git diff themselves.

PR mode:

git diff $(git merge-base HEAD origin/main) > /tmp/review-diff.patch

Local mode:

MERGE_BASE=$(git merge-base HEAD origin/main 2>/dev/null || git merge-base HEAD origin/master)
git diff $MERGE_BASE > /tmp/review-diff.patch
git diff >> /tmp/review-diff.patch

Verify the file was created and is non-empty before proceeding.

Step 1: Spawn Review Subagents

Spawn exactly 3 subagents using the subagent tool. Each should use the zen-review skill.

Default models (use these unless the user's prompt specifies different models):

1. model="opus-4-7-think", skill="zen-review"
2. model="gpt-5-3-codex", skill="zen-review"
3. model="gemini-3-1-pro-preview", skill="zen-review"

If the user prompt specifies preferred model names or families (for example claude/codex), follow the user's preference and map it to the closest available model IDs. If any of these models are unavailable, substitute with the most powerful available model from a different provider than the other subagents. If only 1 provider is available, use its most powerful model for all 3.

For each subagent, set the prompt to:

PR mode: "IMPORTANT: Follow the skill instructions STRICTLY and IN ORDER. The diff is saved at /tmp/review-diff.patch. Your FIRST action MUST be to read that file — do NOT run git diff, do NOT read any other files before you have the diff. Use any PR title and description included in this prompt as additional review context. Review this PR."

Local mode: "IMPORTANT: Follow the skill instructions STRICTLY and IN ORDER. The diff is saved at /tmp/review-diff.patch. Your FIRST action MUST be to read that file — do NOT run git diff, do NOT read any other files before you have the diff. Review the changes on this branch."

Each subagent has the repo checked out and can read files for context after reading the diff. The skill provides review instructions. Each subagent will return a JSON array of findings.

Spawn all 3 in parallel, then await all results.

If a subagent fails or returns invalid output, try to resume the subagent and proceed with the remaining results.

Step 2: Merge and Deduplicate

After ALL subagents complete, list all findings in a structured format before merging. For each finding, note which subagent/model reported it. This makes consensus visible: if 2+ models independently found the same bug, it is very likely real.

Then merge and deduplicate:

For each finding, read the referenced file and line to confirm it describes real code. Drop findings that are clearly wrong when you read the actual code.

For each subagent's findings:

1. Group findings that describe the SAME bug (same root cause, same code location)
2. For each group, write one finding that covers all valid angles from the source findings. Do not drop an angle just because you chose a different one as primary

Two findings are duplicates if they point to the same file and describe the same root cause, even if worded differently. Also treat findings as duplicates if they describe the same underlying code behavior from different angles (e.g. "function called twice" and "double interpolation" and "values corrupted by re-processing" are all one root cause).

Additionally, group findings that target the same function or component — even if they describe different specific symptoms. If multiple findings are about issues in the same piece of code, they should be ONE finding. Pick the most impactful issue and mention others briefly. A good code review leaves at most 1-2 comments per code area.

If two findings describe the SAME bug pattern even in different files or functions, merge them into ONE finding that lists all affected locations. Examples:

• "fire-and-forget async" in file A and file B -> one finding
• "shutdown ordering issue in component X" and "component Y" -> one finding
• findings that differ only in degree ("double application" vs "triple application") -> one finding

Maximum output: aim for no more than 5-7 findings per PR. If you have more, you are likely not grouping aggressively enough. But if the PR is huge, you could have more.

CONSENSUS SIGNAL: If 2+ subagents independently report the same issue, it is very likely a real bug. Do NOT drop consensus findings unless they are clearly wrong.

When in doubt, KEEP the finding. It is better to include a borderline finding than to drop a real bug. Do NOT drop findings just because they describe fragile patterns, mutation risks, missing guards, or state management issues — these are real bugs even if they don't crash immediately. Only drop findings that are genuinely irrelevant to code correctness.

Drop or merge a finding if:

• It is a duplicate of another finding (same bug OR same component OR same pattern)
• It describes a style/formatting issue, not a bug
• Another finding already covers the same function/module (keep the most impactful one, merge the rest into it)
• It is purely speculative with no code evidence
• It describes ONLY a performance concern with no correctness impact (unless it can cause incorrect behavior like OOM, cache corruption, stale data)
• It describes dead code, unused imports, or redundant expressions

Also drop findings (unless clearly defined in task description) that are:

• Test quality issues unless the test will PASS when it should FAIL
• Feature gaps or missing functionality
• Intentional design decisions or tradeoffs
• Tooling/build concerns
• Latent issues with no current runtime impact

CRITICAL RULES:

• Do NOT add new findings. Your output must ONLY contain findings from the subagent results.
• Every subagent finding must appear in your output either as a kept finding or merged into a group. Do not silently drop findings.

Step 3: Present Results

3a. Local Mode — Output Markdown

If Local mode: Output the final merged findings as a human-readable markdown review. Do NOT output raw JSON.

Format:

## Code Review

**Verdict**: [APPROVE if no P0/P1 findings | REQUEST CHANGES if P0/P1 exist]

### Summary
[1-2 sentences: what the changes do and overall assessment]

### Findings

| Priority | Issue | Location |
|----------|-------|----------|
| P0 | {body summary} | [./path/to/file.ts:42](./path/to/file.ts:42) |
| ... | ... | ... |

### Details

#### [severity] Issue title
**File:** [./path/to/file.ts:42](./path/to/file.ts:42)

Description with root cause and consequence.

**Suggested fix:**

code

(Repeat for each P0/P1 finding. P2/P3 items only need the table entry.)

### Recommendation
[Concise actionable recommendation]

If no issues survived merging, output:

## Code Review

**Verdict**: APPROVE

No issues found.

3b. PR mode - Post Review on GitHub

Build the review payload

Create a JSON file at /tmp/review_payload.json:

{
  "event": "COMMENT",
  "body": "",
  "comments": [
    {
      "path": "src/file.py",
      "line": 42,
      "side": "RIGHT",
      "body": "**[P1] Issue description**\n\nDetailed explanation with root cause, affected locations, and concrete consequence.\n\n**Suggested fix:**\n```\ncode\n```"
    }
  ]
}

IMPORTANT: Do NOT put a summary table or findings list in the body.

Severity mapping:

• P0 (Critical): Will crash, lose data, or create security vulnerability
• P1 (High): Significant bug affecting correctness
• P2 (Medium): Real issue but lower impact
• P3 (Low): Minor issue, suggestion

Every inline comment MUST have:

• path: relative file path from repo root
• line: line number in the NEW file (right side of diff)
• side: always "RIGHT" for new/modified code
• body: detailed, self-contained description

Posting rules:

• P0, P1, P2: MUST be inline comments. Never in the body.
• P3: Put in the body as a brief note (not as inline comments).
• No findings at all: Set body to "LGTM".
• No summary table: Never put a summary table or findings overview in the body.

Body format (when P3 findings exist):

• Start with a brief status line referencing the inline comments, e.g.: "Found N issues posted as inline comments above."
• Then list P3 items under a "Low-priority notes" heading.
• Example body: "Found 3 issues posted as inline comments above.\n\nLow-priority notes:\n- file.ts:42 — description of minor issue"

Drop any P0/P1/P2 finding that cannot be tied to a specific file and line.

For each inline comment (P0-P2), the body must include:

• Clear description of the bug and root cause
• Exact code pattern that is wrong (quote the code)
• All affected locations (every file:line)
• Concrete consequence: what breaks at runtime
• If multi-path interaction, explain the full chain

IMPORTANT: Do NOT include internal details in comment bodies. Never mention:

• Consensus counts (e.g. "3/3", "2/3 models agree")
• Model names (e.g. "opus", "codex", "gemini")
• Subagent references (e.g. "Subagent 1 found...") The review should read as if written by a single reviewer.

If no issues survive merging, write: {"comments": [], "event": "COMMENT", "body": "LGTM"}

Verify the diff file

The posting script needs /tmp/review-diff.patch to validate line numbers. This file was already created in Step 0b. Verify it still exists before proceeding.

Run the posting script

Post the review using the strict posting script:

node <SKILL_DIRECTORY>/scripts/post_review_strict.js \
  "$GITHUB_REPOSITORY" "$PR_NUMBER" /tmp/review-diff.patch /tmp/review_payload.json

Where $GITHUB_REPOSITORY and $PR_NUMBER are provided in the prompt.

The script validates every comment line number against the diff:

• Lines within a diff hunk: posted as-is.
• Lines within 5 lines of a hunk: auto-adjusted to the nearest valid line.
• Lines more than 5 lines from any hunk: the script exits with an error showing which comments are invalid, the valid diff ranges for that file, and the nearest valid line.

If the script fails with line errors, you MUST:

1. Read the error output carefully.
2. Update /tmp/review_payload.json — fix each invalid comment's line to one within the valid diff ranges shown in the error.
3. Re-run the script.

The script also automatically adds thumbs-up and thumbs-down reactions to every posted inline comment after a successful post.

This is a non-interactive review run. Do NOT ask questions and do NOT fix code. Post the review, then stop.

---

Error Handling

Cause	Fix
/tmp/review-diff.patch is empty after Step 0b	Verify the diff file exists and is non-empty before spawning subagents. Re-run git diff if needed.
Subagent returns invalid or non-JSON output	Resume the subagent with a corrective prompt. Proceed with results from the other two subagents.
Subagent fails entirely (timeout, crash)	Proceed with results from the remaining subagents. Note the failure in the output.
Posting script fails with invalid line numbers	Read the error output for valid diff ranges. Update /tmp/review_payload.json line numbers to valid ranges. Re-run script.
GITHUB_REPOSITORY or PR_NUMBER not set in environment	Extract from user prompt. Verify format: owner/repo and integer PR number.
node not available to run posting script	Install Node.js 18+. Alternatively, output review as markdown and instruct user to post manually.
All three subagents fail	Output an error review indicating no results could be generated. Do not fabricate findings.
Merged findings exceed 5-7 but all are real bugs	Preserve all valid findings. The 5-7 target is guidance, not a hard limit. Group by code area to reduce count.

Anti-Patterns

Pattern	Problem	Fix
Dropping findings because "only one model found it"	Consensus is a signal, not a requirement. Single-model findings can be valid.	Verify against actual code. Keep if real, drop only if clearly wrong.
Adding original findings not reported by any subagent	Violates the orchestrator's role. Fabricates review content.	Output must contain ONLY findings from subagent results. Never add new ones.
Mentioning model names or consensus counts in PR comments	Reveals internal review mechanics to the author	Write review as if from a single reviewer. No "2/3 models agree" language.
Including style/formatting issues as P0/P1	Inflates severity, dilutes critical findings	P0/P1 reserved for crashes, data loss, security. P2 for code smells. P3 for style.
Posting summary table in PR comment body	Redundant with inline comments, clutters the review	Only body text: status line + P3 notes. All P0-P2 findings go inline.
Silently dropping findings that don't map to a clear file:line	Violates the requirement to not silently drop	Document dropped findings with reason. If they describe real issues, find the nearest code location.
Running git diff inside subagents	Wastes subagent context. Diff may differ between agents.	Pre-save diff to /tmp/review-diff.patch. Subagents read that file only.
Reviewing pre-existing code not in the diff	Scope creep. Reviews irrelevant code.	Only review code in the diff. Pre-existing issues are out of scope.

Checklist

• All subagents dispatched and returned results before merging
• Findings deduplicated across model outputs
• False positives filtered out (models may flag non-issues)
• Priority levels assigned (P0 critical, P1 major, P2 minor, P3 suggestion)
• PR description or context reviewed — changes make sense in the broader feature context

Sources

• Google Engineering Practices — "How to Do a Code Review" (google.github.io/eng-practices)
• SmartBear — "Best Practices for Code Review" (smartbear.com)
• Palantir — "Code Review Best Practices" (blog.palantir.com)
• GitHub Docs — "About Pull Request Reviews" (docs.github.com)
• Microsoft — "Code Review Checklist" (learn.microsoft.com)
• OWASP Code Review Guide — owasp.org/www-project-code-review-guide
• Conventional Comments — conventionalcomments.org