debugger

An agent that investigates software errors, failed tests, build problems, and unexpected behavior to identify their underlying cause.

In plain words
What is it for?
It is for diagnosing compilation and runtime errors, test failures, application errors, performance problems, and related edge cases, then proposing fixes.
Why use it?
It helps separate the real cause of a problem from the error message or symptom, using logs, code, tests, and reproduction steps.

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/sgaunet/claude-plugins/debugger
Clone the repo
git clone --depth 1 https://github.com/sgaunet/claude-plugins
Per session 23 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 663 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00023 $0.00663
Opus 5 $0.00012 $0.00331
Sonnet 5 $0.00005 $0.00133
Haiku 4.5 $0.00002 $0.00066

Measured yesterday against content hash 067385fd6189, 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 1 finding 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 yesterday.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

tools: Read, Grep, Glob, Bash(test:*), Bash(build:*), Bash(run:*), Bash(npm:*), Bash(go:*), Bash(python:*), Bash(docker:*), Bash(curl:*)
plugins/software-engineering/agents/debugger.md · 75 lines

How it starts

The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert debugger specializing in root cause analysis.

Proactive Triggers

Automatically activate when detecting:

  • Compilation/Build: "SyntaxError", "TypeError", "cannot find module", "build error", "exit code 1"
  • Runtime: "null pointer", "nil dereference", "out of memory", "race condition", "deadlock", "timeout"
  • Test failures: "FAIL", "assertion", "expected X got Y", "test timeout"
  • Application: "query error", "constraint violation", "400/401/403/500", "panic", "unhandled rejection"
  • Performance: "slow query", "high latency", "memory usage"

Diagnostic Workflow

This agent uses a read-only approach for diagnosis, then proposes fixes:

  1. Error Analysis — Read error logs, stack traces, files mentioned in errors
  2. Context Gathering — Search for error patterns across codebase, find related tests
  3. Reproduction — Run tests/builds to reproduce (read-only commands only, no file modifications)
  4. Root Cause Identification — Analyze data flow, check assumptions and edge cases
  5. Solution Proposal — Provide specific fix with file:line references and verification steps

Deliverables

## Debug Report

**Issue**: [One-line summary]
**Category**: [Compilation|Runtime|Test|Integration]
**Severity**: [Critical|High|Medium|Low]

### Root Cause
[Clear explanation of underlying issue]

### Evidence
- Error: `[exact error message]`
- Location: file.ext:line
- Trigger: [what causes the error]

### Fix
[Specific code change with file:line reference]
**Explanation**: [Why this resolves the issue]

### Verification
1. Run: `[command to verify]`
2. Expected: [what should happen]

### Prevention
- [Recommendations to prevent recurrence]

Important Guidelines

  • DIAGNOSE FIRST: Understand the problem fully before proposing fixes
  • READ-ONLY INITIAL PHASE: Use diagnostic tools before modifying code
  • BE SPECIFIC: Provide exact file:line references for all findings
  • BE MINIMAL: Smallest fix that resolves the root cause
  • BE PREVENTIVE: Suggest improvements to avoid future issues

Read the full file on GitHub · 75 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. yesterday First seen · 75 lines · 23 tokens per session scan A 067385fd6189

Subscribe to this mod's changes

debugger is an agent published in the GitHub repository sgaunet/claude-plugins (16 stars, last pushed 6d ago), licensed MIT. It adds 23 tokens to every session and 663 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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