# Code reviewer > Use when one specific diff must be read for defects, with no wider audit. Review a specified code change for actionable defects. Use for uncommitted changes, base-branch diffs, commits, PRs or MRs; review alone is read-only, and requested fixes follow the review. Not a repository-wide security or complexity audit. ## Facts - Type: Agent skill - Discipline: Engineering - Author: Matt Silverlock (https://github.com/elithrar) - Upstream: https://github.com/elithrar/dotfiles/blob/main/.agents/skills/code-reviewer/SKILL.md - Source file: https://raw.githubusercontent.com/elithrar/dotfiles/main/.agents/skills/code-reviewer/SKILL.md (4410 bytes, sha256:47d38bfe1082443e779667f85162b7ddb5085402b2e2511ef4d7cc72cf228f5c) - Licence: MIT - Upstream copy last changed: 2026-09-17 - Status: listed, not yet ruled on by the curator ## Use it I want to use the Code reviewer skill by Matt Silverlock. This is what it does, in the author's own words: Review a specified code change for actionable defects. Use for uncommitted changes, base-branch diffs, commits, PRs or MRs; review alone is read-only, and requested fixes follow the review. Not a repository-wide security or complexity audit. Download the whole folder at https://github.com/elithrar/dotfiles/tree/main/.agents/skills/code-reviewer, SKILL.md and every file beside it, into your skills directory: ~/.claude/skills/code-reviewer/ for Claude Code, ~/.agents/skills/code-reviewer/ for Codex, ~/.cursor/skills/code-reviewer/ for Cursor. Get it from the author's repo, not from startupskills.dev. Then tell me the path you installed it to and how to invoke it. Nothing here is vendored: install from the author's repo, not from this site. A verbatim copy of the author's file follows for reading, under the licence reproduced after it; the current file is in the author's repo. ## Links - Page: https://startupskills.dev/elithrar/code-reviewer - Author: https://startupskills.dev/elithrar - Index: https://startupskills.dev/llms.txt ## The file itself --- name: code-reviewer description: Review a specified code change for actionable defects. Use for uncommitted changes, base-branch diffs, commits, PRs or MRs; review alone is read-only, and requested fixes follow the review. Not a repository-wide security or complexity audit. --- # Code Reviewer Keep review-only requests read-only. When the user also requests fixes, a PR, or posted findings, complete the review and then perform the authorized follow-up. The skill does not authorize additional external actions. Use the target named by the user. If no target is given, review uncommitted changes. If the working tree is clean, report that no uncommitted target exists rather than silently reviewing the last commit. Review behavior introduced or materially affected by the change. Mention a pre-existing problem only when the change worsens it or depends on an invalid assumption about it. ## Workflow 1. Read the applicable `AGENTS.md` and repository review instructions. 2. Resolve the exact review target and inspect the complete diff. 3. For a base-branch review, resolve the requested base and compute its merge base with the review head. Prefer the remote-tracking ref of that base when it is ahead of its local ref; the feature branch's own upstream is not the base. 4. Read enough surrounding implementation, tests, callers, and configuration to understand each changed path. 5. Identify the intended behavior, preserved invariants, externally reachable paths, and highest-risk changes. 6. Verify each candidate finding from code, relevant history, or the smallest diagnostic check that can confirm or disprove it. 7. Continue through the complete diff after finding an issue. 8. Reread the cited code and report only findings that survive final validation. ## Validation Prefer repository instructions and configured project commands. Run a targeted check only when it can confirm or disprove a candidate finding or material regression. Do not install dependencies, invoke generic package runners that may download tools, or run broad suites solely because a manifest exists. Attribute a failure to the reviewed change before presenting it as a finding. Otherwise report it as a verification limitation. ## Review Focus Look for meaningful, change-introduced defects involving: - Correctness and state transitions. - Authorization, validation, secrets, or data exposure. - Concurrency, persistence, retries, or partial failure. - Public contracts and compatibility. - Performance on reachable paths and realistic input sizes. - Maintainability only when the change creates concrete bug risk or costly coupling. Spend the most depth on high-impact or externally reachable paths. Do not report style preferences, speculative future concerns, intentional behavior changes, pre-existing problems, or mechanical issues already enforced reliably by configured tooling. ## Finding Standard Report a finding only when all of these are true: - It affects correctness, security, performance, or maintainability meaningfully. - It is discrete and actionable. - It was introduced by the reviewed change. - The affected input, state, sequence, or call path can be demonstrated. - The author would probably fix it if they knew about it. Cite the smallest changed line range that causes the issue. The cited range must overlap the reviewed diff. Explain the concrete scenario in the finding paragraph. Drop speculative concerns and findings that cannot be tied to the reviewed change. ## Review Passes Use multiple focused passes when useful, but do not delegate unless the user or host workflow explicitly requests independent reviewers. Revalidate every compiled finding against the code. Disagreement is a reason to inspect further, not to choose the higher severity. ## Output Present findings first, ordered by priority. Use one entry per issue: ```text [P1] Imperative finding title — path/to/file.ts:42 ``` Follow with one short paragraph describing the affected scenario and why the behavior is wrong. Add a fix direction only when it is not obvious. - `P0`: Universal release blocker or critical failure. - `P1`: Urgent defect that should be fixed next. - `P2`: Ordinary defect that should be fixed. - `P3`: Low-impact issue still worth fixing. If no finding qualifies, say `No findings.` Then add a brief overall assessment and any material test gaps or residual risks. ## Licence of the file above The file above is https://raw.githubusercontent.com/elithrar/dotfiles/main/.agents/skills/code-reviewer/SKILL.md, by Matt Silverlock, reproduced without changes. - Source: https://github.com/elithrar/dotfiles/blob/main/.agents/skills/code-reviewer/SKILL.md - Copyright: Copyright (c) 2014 Matt Silverlock - Licence: MIT, https://raw.githubusercontent.com/elithrar/dotfiles/main/LICENSE The repo's licence file, verbatim from https://raw.githubusercontent.com/elithrar/dotfiles/main/LICENSE: The MIT License (MIT) Copyright (c) 2014 Matt Silverlock Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.