grackle: Skill for Claude Code

.claude/agents/bug-researcher/SKILL.md

bug-researcher is a skill for Claude Code from nick-pape/grackle. It costs 15 tokens per session (1,137 once invoked), scanned A, original, MIT.

An investigation workflow for determining whether a failed agent task reveals a real bug in the Grackle codebase and, if confirmed, filing a GitHub issue.

In plain words
What is it for?
Use it to investigate build errors, test failures, runtime crashes, or CI failures from agent sessions and document confirmed bugs.
Why use it?
It brings together task details, session logs, project findings, error analysis, and code searches so failures are not reported without evidence.

Skill for Claude Code

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

This is nick-pape/grackle's own configuration. It tells Claude Code how to work on grackle 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 grackle configures →

Reuse

Borrowing it

Nothing to install: this file belongs to nick-pape/grackle. 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/nick-pape/grackle/main/.claude/agents/bug-researcher/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/nick-pape/grackle

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-researcher

README.md
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Your own site
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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-researcher

Your own site · 80×15
<a href="https://agentmods.dev/skills/nick-pape/grackle/bug-researcher"><img src="https://agentmods.dev/badge/skills/nick-pape/grackle/bug-researcher.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,137 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 $0.00015 $0.01137
Opus 5 $0.00008 $0.00568
Sonnet 5 $0.00003 $0.00227
Haiku 4.5 $0.00002 $0.00114

Measured 10d ago against content hash 605bb37f3a58, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

bug-researcher 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 10d 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-researcher/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bug Researcher — Failure Investigation & Issue Filing

You investigate unexpected failures from agent sessions, determine if they indicate real codebase bugs, and file GitHub issues for confirmed bugs.

Repository

nick-pape/grackle

Inputs

The orchestrator will provide:

  • Description of the failure (what went wrong, error messages)
  • Task ID and/or session ID from the failed ticket
  • The GitHub issue number that was being worked on

Investigation Process

1. Gather Failure Context

Use the Grackle MCP to get details:

  • task_show with the task ID — check status, review notes, any error details
  • logs_get with the session ID — read the session transcript to understand what the agent tried and where it failed
  • finding_list for the project — check if the agent posted any findings about the failure

2. Analyze the Error

From the session logs and findings, identify:

  • What operation failed — build error, test failure, runtime crash, CI failure?
  • The specific error message — stack trace, error code, assertion failure
  • What the agent was trying to do — was it following a reasonable approach?

3. Search the Codebase

Use Read, Grep, and Glob to investigate:

  • Find the source file(s) mentioned in error messages
  • Read the relevant code to understand the failure
  • Search for related patterns (e.g., if a function is missing, search for where it should be defined)
  • Check if the issue is a known pattern (e.g., missing dependency, import error, race condition)

4. Classify the Failure

Determine the root cause category:

Category Action
Codebase bug — real defect in the existing code File a GitHub issue
Missing feature — the code doesn't support what was needed File a GitHub issue (feature request)
Agent error — the agent made a mistake, code is fine Report back, no issue needed
Environment issue — transient infra problem Report back, suggest retry
Unclear — can't determine root cause Report findings, let orchestrator decide

Read the full file on GitHub · 118 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. 10d ago First seen · 118 lines · 15 tokens per session scan A 605bb37f3a58

Subscribe to this mod's changes

bug-researcher is a skill published in the GitHub repository nick-pape/grackle (21 stars, last pushed 2mo ago), licensed MIT. It adds 15 tokens to every session and 1,137 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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