checker

checker is an agent for Claude Code from cordwainersmith/Claudoscope. It costs 63 tokens per session (337 once invoked), scanned A, original, MIT.

An independent checker for completed coding work. It reruns tests, tries the affected feature, and probes unusual cases before returning either CONFIRMED or REFUTED.

In plain words
What is it for?
Use it to review a stated outcome together with its code changes or file paths. It is useful for checking behavior, edge cases, authentication, secrets, and input validation without editing the project.
Why use it?
It reduces the risk of accepting a change just because the original implementer said it worked. A failed check includes the specific situation where the claimed result breaks.

Agent for Claude Code

Written for Claude Code: effort in frontmatter. Also seen: model in frontmatter; names the NotebookEdit tool.

Good fit Use it to review a stated outcome together with its code changes or file paths. It is useful for checking behavior, edge cases, authentication, secrets, and input validation without editing the project.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/cordwainersmith/claudoscope/checker
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.

Clone the repo
git clone --depth 1 https://github.com/cordwainersmith/Claudoscope

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 checker

README.md
[![agentmods](https://agentmods.dev/badge/agents/cordwainersmith/claudoscope/checker/github.svg)](https://agentmods.dev/agents/cordwainersmith/claudoscope/checker)
Your own site
<a href="https://agentmods.dev/agents/cordwainersmith/claudoscope/checker"><img src="https://agentmods.dev/badge/agents/cordwainersmith/claudoscope/checker/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.

agentmods 80×15 button for checker

Your own site · 80×15
<a href="https://agentmods.dev/agents/cordwainersmith/claudoscope/checker"><img src="https://agentmods.dev/badge/agents/cordwainersmith/claudoscope/checker.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 63 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 337 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00063 $0.00337
Opus 5.5 $0.00025 $0.00135
Sonnet 5.5 $0.00013 $0.00067
Haiku 4.5 $0.00006 $0.00034

Measured 1mo ago against content hash 3706f4fbd193, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

checker 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.

Claudoscope/Resources/RoutingStack/agents/checker.md · 18 lines

What it actually says

You verify with fresh eyes and an adversarial goal. You receive a claim, something like "X was implemented and works", plus the relevant diff or file paths. Your job is to try to refute it: rerun the tests yourself rather than trusting the implementer's run, exercise the affected flow, probe the edge cases the diff doesn't obviously handle.

Return exactly one verdict, CONFIRMED or REFUTED. A refutation needs the exact failure scenario: the input or state that triggers it, what actually happens versus what should happen, and where in the code it breaks.

Never edit or fix anything, not even a one-line typo; your tools don't allow it, and that's deliberate. Independence is your entire value here. Whoever asked for the check owns the fix and the follow-up.

When the work under review touches authentication, secrets, or input validation, be exhaustive rather than economical: look for abuse cases and boundary bypasses, not only the functional path the implementer tested.

Run long commands in the foreground with an explicit timeout, ten minutes at most. Never detach a process. If a command cannot finish inside ten minutes, report the exact command and its context instead of starting it, and stop.

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. 1mo ago First seen · 18 lines · 63 tokens per session scan A 3706f4fbd193

Subscribe to this mod's changes

checker is an agent published in the GitHub repository cordwainersmith/Claudoscope (260 stars, last pushed 5d ago), licensed MIT. It adds 63 tokens to every session and 337 once invoked, about $0.0003 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.

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