mathilda: Agent for Claude Code

.claude/agents/bug-hunter.md

bug-hunter is an agent for Claude Code from stblake/mathilda. It costs 60 tokens per session (692 once invoked), scanned A, original, GPL-3.0.

An agent that examines recent code changes across multiple files to look for bugs, logic mistakes, and regressions.

In plain words
What is it for?
Use it to trace how changed code runs and investigate possible failures before deployment.
Why use it?
It helps find defects introduced by a specific set of changes before they reach users.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

This is stblake/mathilda's own configuration. It tells Claude Code how to work on mathilda itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mathilda configures →

Reuse

Borrowing it

Nothing to install: this file belongs to stblake/mathilda. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/stblake/mathilda/main/.claude/agents/bug-hunter.md
Clone the repo
git clone --depth 1 https://github.com/stblake/mathilda

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 bug-hunter

README.md
[![agentmods](https://agentmods.dev/badge/agents/stblake/mathilda/bug-hunter/github.svg)](https://agentmods.dev/agents/stblake/mathilda/bug-hunter)
Your own site
<a href="https://agentmods.dev/agents/stblake/mathilda/bug-hunter"><img src="https://agentmods.dev/badge/agents/stblake/mathilda/bug-hunter/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 bug-hunter

Your own site · 80×15
<a href="https://agentmods.dev/agents/stblake/mathilda/bug-hunter"><img src="https://agentmods.dev/badge/agents/stblake/mathilda/bug-hunter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 60 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 692 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 unknown 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 $0.00060 $0.00692
Opus 5.5 $0.00024 $0.00277
Sonnet 5.5 $0.00012 $0.00138
Haiku 4.5 $0.00006 $0.00069

Measured 2mo ago against content hash 9a9fb88eae78, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

bug-hunter 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 2mo 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.

.claude/agents/bug-hunter.md · 77 lines

The source is not reproduced here

Licensed GPL-3.0

The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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. 2mo ago First seen · 77 lines · 60 tokens per session scan A 9a9fb88eae78

Subscribe to this mod's changes

bug-hunter is an agent published in the GitHub repository stblake/mathilda (20 stars, last pushed yesterday), licensed GPL-3.0. It adds 60 tokens to every session and 692 once invoked, about $0.0002 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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