Signal Review

⚡ signal-review — Templated Code Review

One line per issue. Severity required. Summary at the end. No prose.

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Invocation Triggers

Activate when user says any of:

• /signal-review
• "review this", "review my code", "review this file"
• "check this PR", "code review", "look at this diff"
• "what's wrong with this", "any issues with this code"

Target can be: a file, a diff, a PR URL, a code block, or the current working directory.

Slash command behavior

If the user's message is only /signal-review, treat that as review now.

• Do not stop after acknowledging the skill.
• Do not ask for confirmation unless the user explicitly asked for draft / dry behavior.
• Immediately inspect the provided target (or current working context) and output the review

in the format below in the same turn.

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Output Format

One line per issue:

{file}:{line}|{issue}|{severity:1-5}|{fix}

Full example:

auth.js:47|nullref on empty arr|4|add guard clause before map
api.js:103|missing await on async call|5|add await
utils.js:12|unused import lodash|1|remove import
∑ 3 issues [1×sev5, 1×sev4, 1×sev1]  critical→api.js:103

Rules:

• Severity is required on every line. No exceptions.
• Issue description: max ~60 chars, imperative noun phrase ("nullref on empty arr", not "there is a null reference error")
• Fix: max ~50 chars, imperative ("add guard clause before map", not "you should add a guard clause")
• Order by severity descending (sev5 first)
• One summary line at the end, always

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Summary Line Format

∑ {N} issues [{breakdown}]  critical→{highest-sev-location}

Examples:

∑ 5 issues [2×sev5, 1×sev3, 2×sev1]  critical→auth.js:47
∑ 1 issue [1×sev2]
∑ 0 issues ✓

If zero issues: output only ∑ 0 issues ✓. No explanation, no praise.

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Severity Scale

Full definitions in [references/severity.md](../../references/severity.md). Quick reference:

| Level | Meaning | |---|---| | 5 | Breaks in production, security vulnerability, data loss | | 4 | Likely runtime error, will crash under normal use | | 3 | Wrong behavior under specific conditions, logic error | | 2 | Code smell, maintainability issue, confusing pattern | | 1 | Style, minor cleanup, nitpick |

Severity assignment rule: Assign based on impact when triggered, not probability of triggering. A SQL injection that only fires on a specific input is still sev5.

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What to Review

In order of priority:

1. Security — injection, auth bypass, exposed secrets, insecure defaults
2. Correctness — logic errors, missing error handling, race conditions, off-by-one
3. Runtime safety — null dereferences, unhandled promises, type mismatches
4. Performance — N+1 queries, unnecessary re-renders, missing indexes, sync-in-loop
5. Maintainability — dead code, magic numbers, unclear naming, deep nesting
6. Style — only if it affects readability, never as a primary finding

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Scope Inference

If the user doesn't specify what to review:

• File open in editor → review that file
• Recent diff → review the diff (git diff HEAD)
• PR URL provided → fetch with gh pr diff {url} and review
• Code block in message → review exactly what was shared

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Flags

| Flag | Behavior | |---|---| | --quick | Sev3+ only. Skip style and nitpicks. | | --security | Security-focused pass only. | | --sev {N} | Only report issues at severity N or above. | | --fix | After listing issues, output the corrected code block. |

--fix output: List all issues first, then output the corrected file or function in a single code block. Do not mix issue lines with code.

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Multi-File Reviews

When reviewing multiple files, group by file:

auth.js:
  auth.js:47|nullref on empty arr|4|add guard clause before map
  auth.js:89|hardcoded secret|5|move to env var

api.js:
  api.js:103|missing await|5|add await

∑ 3 issues [2×sev5, 1×sev4]  critical→api.js:103

The summary line covers all files combined.

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BOOT Integration

If BOOT:review is active (see [references/boot-presets.md](../../references/boot-presets.md)):

• Output format is already set to TMPL:rev
• Severity is already required by severity_required
• No preamble, no summary prose — just the lines and the ∑ line
• If the active template cannot be satisfied, emit SIGNAL_DRIFT: instead of falling back to prose

If SIGNAL is not active, still use this format. The template is the default for this skill regardless of SIGNAL mode.

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Eat Your Own Cooking

This skill's own output must comply with SIGNAL compression rules if SIGNAL is active:

• No "Here are the issues I found:" preamble
• No "Overall, the code looks pretty good except..." summary
• First line is an issue line or ∑ 0 issues ✓
• Last line is always the ∑ summary

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: mattbaconz
• Source: mattbaconz/signal
• License: MIT

Install and usage instructions live in the source repository linked above.