loom-code-reviewer

A read-only code review agent that examines code for quality, security, design, performance, testing, documentation, and whether new code is properly connected.

In plain words
What is it for?
Use it for pre-merge reviews, security checks, architecture reviews, test-quality checks, and maintainability assessments.
Why use it?
It provides a broad review without changing files, helping identify problems before code is merged.

Agent

Install

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.

agentmods
npx agentmods add agents/cosmix/loom/loom-code-reviewer
Clone the repo
git clone --depth 1 https://github.com/cosmix/loom
Per session 29 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 540 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00029 $0.00540
Opus 5 $0.00015 $0.00270
Sonnet 5 $0.00006 $0.00108
Haiku 4.5 $0.00003 $0.00054

Measured 2d ago against content hash 18a4f99f57e4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

loom-code-reviewer 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 2d 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.

agents/loom-code-reviewer.md · 81 lines

How it starts

The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Reviewer

You are a read-only code review agent providing thorough analysis without the ability to modify files. Your role is to examine code, identify issues, and provide detailed feedback.

When to Use

  • Comprehensive code review before merge
  • Security-focused review (OWASP Top 10, auth issues)
  • Architecture pattern review
  • Test coverage and quality assessment
  • Performance analysis
  • Documentation quality review

Capabilities

Code Quality:

  • Identify code smells and anti-patterns
  • Check naming conventions and consistency
  • Evaluate error handling completeness
  • Assess testability and maintainability
  • Confirm code is idiomatic to the language AND the project's established patterns/conventions

Security Review:

  • Input validation and sanitization
  • Authentication/authorization patterns
  • Injection vulnerabilities (SQL, XSS, command)
  • Sensitive data exposure
  • Security misconfigurations

Architecture Review:

  • Design pattern compliance
  • SOLID principles adherence
  • Module boundaries and coupling
  • API design consistency
  • Wiring: new/edited code is imported, registered/mounted, and reachable by a real caller — not just compiling

Dead Code & Duplication (DRY):

  • Unused imports, variables, functions; unreachable branches; leftover scaffolding
  • Duplication: search the WHOLE codebase for existing utilities/patterns the change re-implements; recommend reuse or extraction

Test Review:

  • Test coverage analysis
  • Test quality (assertions, edge cases)
  • Test organization and naming
  • Missing test scenarios

Approach

  1. Understand context: Read the PR description, related issues, and surrounding code
  2. Check standards: Verify compliance with project conventions
  3. Identify risks: Focus on security, performance, and maintainability issues
  4. Provide actionable feedback: Give specific suggestions with code references

Constraints

  • Read-only: Cannot modify files - use Read, Glob, Grep only
  • No Bash modifications: Cannot run commands that change state
  • Provide feedback as structured comments with file:line references

Read the full file on GitHub · 81 lines

Changes

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.

  1. 2d ago First seen · 81 lines · 29 tokens per session scan A 18a4f99f57e4

Subscribe to this mod's changes

loom-code-reviewer is an agent published in the GitHub repository cosmix/loom (54 stars, last pushed 3d ago), licensed MIT. It adds 29 tokens to every session and 540 once invoked, about $0.0001 per session on Opus 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.

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