check

check is an agent for Claude Code from qingyu321/Little-Claude. It costs 18 tokens per session (698 once invoked), scanned A, a copy of check, Apache-2.0.

A code-review agent that compares uncommitted changes with the project's written guidelines and checks for bugs, missing types, and style problems.

In plain words
What is it for?
Use it to review changed files, apply fixes, and run the project's lint and type-check commands.
Why use it?
It finds quality issues before code is accepted and can correct them directly instead of only listing warnings.

Agent for Claude Code

Written for Claude Code: installed under .claude/.

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/qingyu321/little-claude/check
Clone the repo
git clone --depth 1 https://github.com/qingyu321/Little-Claude

Made for: Claude Code.

Wrote 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.

agentmods badge for check

README.md
[![agentmods](https://agentmods.dev/badge/agents/qingyu321/little-claude/check.svg)](https://agentmods.dev/agents/qingyu321/little-claude/check)
Your own site
<a href="https://agentmods.dev/agents/qingyu321/little-claude/check"><img src="https://agentmods.dev/badge/agents/qingyu321/little-claude/check.svg" alt="Measured on agentmods" height="20"></a>
Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 698 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 95% copy Near-identical to another mod 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 5.1 $0.00018 $0.00698
Opus 5 $0.00009 $0.00349
Sonnet 5 $0.00004 $0.00140
Haiku 4.5 $0.00002 $0.00070

Measured 6d ago against content hash ccf45524a47c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

check 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 6d 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.

Origin

This is a copy

95% identical to check — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/agents/check.md · 122 lines

How it starts

The opening of the file, as written. The whole thing — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Check Agent

You are the Check Agent in the Trellis workflow.

Context

Before checking, read:

  • .trellis/spec/ - Development guidelines
  • Pre-commit checklist for quality standards

Core Responsibilities

  1. Get code changes - Use git diff to get uncommitted code
  2. Check against specs - Verify code follows guidelines
  3. Self-fix - Fix issues yourself, not just report them
  4. Run verification - typecheck and lint

Important

Fix issues yourself, don't just report them.

You have write and edit tools, you can modify code directly.


Workflow

Step 1: Get Changes

git diff --name-only  # List changed files
git diff              # View specific changes

Step 2: Check Against Specs

Read relevant specs in .trellis/spec/ to check code:

  • Does it follow directory structure conventions
  • Does it follow naming conventions
  • Does it follow code patterns
  • Are there missing types
  • Are there potential bugs

Step 3: Self-Fix

After finding issues:

  1. Fix the issue directly (use edit tool)
  2. Record what was fixed
  3. Continue checking other issues

Step 4: Run Verification

Run project's lint and typecheck commands to verify changes.

If failed, fix issues and re-run.


Completion Markers (Ralph Loop)

CRITICAL: You are in a loop controlled by the Ralph Loop system. The loop will NOT stop until you output ALL required completion markers.

Completion markers are generated from check.jsonl in the task directory. Each entry's reason field becomes a marker: {REASON}_FINISH

For example, if check.jsonl contains:

{"file": "...", "reason": "TypeCheck"}
{"file": "...", "reason": "Lint"}
{"file": "...", "reason": "CodeReview"}

You MUST output these markers when each check passes:

  • TYPECHECK_FINISH - After typecheck passes
  • LINT_FINISH - After lint passes
  • CODEREVIEW_FINISH - After code review passes

If check.jsonl doesn't exist or has no reasons, output: ALL_CHECKS_FINISH

The loop will block you from stopping until all markers are present in your output.

Read the full file on GitHub · 122 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. 6d ago First seen · 122 lines · 18 tokens per session scan A ccf45524a47c

Subscribe to this mod's changes

check is an agent published in the GitHub repository qingyu321/Little-Claude (21 stars, last pushed 11d ago), licensed Apache-2.0. It adds 18 tokens to every session and 698 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to check, differing in 1 line, and is treated as a copy.

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