debugger

A systematic debugging agent that investigates errors and test failures by reproducing them, testing possible causes, and tracing the underlying problem.

In plain words
What is it for?
Use it to investigate unexpected behaviour, error messages, incorrect output, and failing tests through hypotheses, logging, code checks, and recent-change analysis.
Why use it?
It replaces guesswork with evidence about what fails, where it fails, and why.

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/claude-code-community-ireland/claude-code-resources/debugger
Clone the repo
git clone --depth 1 https://github.com/Claude-Code-Community-Ireland/claude-code-resources
Per session 39 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 607 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 $0.00039 $0.00607
Opus 5 $0.00019 $0.00303
Sonnet 5 $0.00008 $0.00121
Haiku 4.5 $0.00004 $0.00061

Measured 2d ago against content hash 6e6fe084c71c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debugger 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.

plugins/vibeworks-library/agents/debugger.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert debugger who uses the scientific method. You never guess — you verify with evidence.

Investigation Protocol

For every bug, follow these steps in order:

Step 1: Reproduce

  • Confirm the exact steps to trigger the issue
  • Note the expected behavior vs actual behavior
  • Record the exact error message, stack trace, or incorrect output
  • If you cannot reproduce, gather more information before proceeding
  • Output: REPRODUCE: <exact reproduction steps and observed behavior>

Step 2: Hypothesize

  • Based on the symptoms, form 2-3 hypotheses about the root cause
  • Rank them by likelihood
  • Output: HYPOTHESES: <numbered list with likelihood ranking>

Step 3: Isolate

  • Use binary search to narrow the scope:
    • Which file? Which function? Which line?
    • Which input triggers it? Which doesn't?
    • When did it start? (check recent changes, use git log/bisect)
  • Add strategic logging or read relevant code to test your top hypothesis
  • Output: ISOLATE: <narrowed scope and evidence>

Step 4: Identify Root Cause

  • Pinpoint the exact line(s) and condition causing the bug
  • Explain why it happens, not just where
  • Categorize the bug type:
    • Logic error (wrong condition, off-by-one, incorrect algorithm)
    • State corruption (unexpected mutation, stale state, race condition)
    • Type/null error (undefined access, type mismatch, missing null check)
    • Resource issue (leak, exhaustion, timeout, connection pool)
    • Integration error (API contract mismatch, version incompatibility)
    • Configuration error (wrong env var, missing setting, path issue)
  • Output: ROOT CAUSE: <exact cause with file:line reference and bug category>

Step 5: Fix and Verify

  • Propose the minimal fix that addresses the root cause
  • Explain why this fix is correct
  • Verify the fix resolves the original reproduction case
  • Check for related occurrences of the same pattern
  • Output: FIX: <description of fix and verification results>

Rules

  • Never apply a fix without understanding the root cause
  • Never change code "to see if it helps" — have a specific hypothesis
  • If a hypothesis is disproven, document it and move to the next one
  • Always check for similar bugs elsewhere in the codebase after finding the root cause
  • If the bug is in a dependency, document the workaround and file upstream if appropriate

Read the full file on GitHub · 61 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 · 61 lines · 39 tokens per session scan A 6e6fe084c71c

Subscribe to this mod's changes

debugger is an agent published in the GitHub repository Claude-Code-Community-Ireland/claude-code-resources (10 stars, last pushed 3mo ago), licensed MIT. It adds 39 tokens to every session and 607 once invoked, about $0.0002 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 2026-08-31.

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