Agent Skills is a collection and marketplace of reusable instruction sets that teach AI agents specific workflows, tasks, or domain knowledge, with supporting files such as scripts, templates, and examples. It is for people who want to install, browse, create, or contribute portable skills for compatible agents. The catalogue entries are individual skills from this collection.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add block/agent-skills --skill code-reviewgit clone --depth 1 https://github.com/block/agent-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/block/agent-skills/code-review)<a href="https://agentmods.dev/skills/block/agent-skills/code-review"><img src="https://agentmods.dev/badge/skills/block/agent-skills/code-review/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/block/agent-skills/code-review"><img src="https://agentmods.dev/badge/skills/block/agent-skills/code-review.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00011 | $0.00243 |
| Opus 5.5 | $0.00004 | $0.00097 |
| Sonnet 5.5 | $0.00002 | $0.00049 |
| Haiku 4.5 | $0.00001 | $0.00024 |
Grade A, and why
code-review scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Code Review Checklist
When reviewing code, check each of these areas:
Functionality
- Code does what the PR description claims
- Edge cases are handled
- Error handling is appropriate
Code Quality
- Follows project style guide
- No hardcoded values that should be configurable
- Functions are focused and well-named
Testing
- New functionality has tests
- Tests are meaningful, not just for coverage
- Existing tests still pass
Security
- No credentials or secrets in code
- User input is validated
- SQL queries are parameterized
Performance
- No obvious performance issues
- Database queries are optimized
- No unnecessary loops or iterations
Documentation
- Public APIs are documented
- Complex logic has comments explaining "why"
- README updated if needed
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 51 lines · 11 tokens per session scan A 0ea793c39def
code-review is a skill published in the GitHub repository block/agent-skills (25 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 11 tokens to every session and 243 once invoked, about $0.0000 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
plugin-quality
A review guide for checking Zhin.js plugins before release. It covers plugin structure, feature declarations, resource cleanup, message sending, and security.
code-review
Code review for issues, style consistency, best practices—use for full code evaluation; not for debugging specific errors or fixing individual style violations.
code-review
Review code for quality, maintainability, and correctness.
quality-gate
Orchestrates the QUALITY pipeline stage for egregore work items, running code review, unbloat, and test updates. Use when running quality checks before a PR.
plugin-review
Review plugin quality with tiered checks and dependency scoping. Use for PR and pre-release audits.
code-review
Structured code review prompt with language and focus area.