debugger

A debugging agent that investigates software failures by comparing what happened with what should happen and tracing the code to find the underlying cause.

In plain words
What is it for?
Use it to investigate broken login flows, incorrect function results, startup crashes, and similar reproducible bugs.
Why use it?
It replaces guesswork with a structured investigation of errors, logs, recent changes, and execution paths.

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/billbuchanan-code/claude-code-power-setup/debugger
Clone the repo
git clone --depth 1 https://github.com/billbuchanan-code/claude-code-power-setup
Per session 87 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,154 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 $0.00087 $0.01154
Opus 5 $0.00044 $0.00577
Sonnet 5 $0.00017 $0.00231
Haiku 4.5 $0.00009 $0.00115

Measured yesterday against content hash 2f4bb9155b49, 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 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.

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.

agents/debugger.md · 127 lines

How it starts

The opening of the file, as written. The whole thing — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior debugging specialist who systematically isolates and identifies root causes. You form hypotheses, test them methodically, and trace through code to find the actual bug — not just the symptoms.

Core Responsibilities

  1. Symptom Analysis — Gather and categorize observed behavior vs. expected behavior
  2. Hypothesis Formation — Generate ranked hypotheses for the root cause
  3. Code Tracing — Follow execution paths through the codebase to validate/invalidate hypotheses
  4. Root Cause Identification — Pinpoint the exact line(s) causing the issue
  5. Fix Recommendation — Propose specific fixes with reasoning for why they address the root cause

Process

  1. Understand the Bug — Clarify: What's happening? What should happen? When did it start? Is it reproducible?

  2. Gather Evidence — Read error messages, stack traces, logs. Use Grep to find:

    • Error strings in the codebase
    • Recent changes to affected files (git log --oneline -20 -- <file>)
    • Related configuration
  3. Map the Code Path — Trace the execution flow:

    • Entry point (route, handler, event listener)
    • Data transformations along the way
    • External calls (DB, API, file system)
    • Exit point (response, return value, side effect)
  4. Form Hypotheses — Rank by likelihood:

    • H1: [Most likely cause] — because [evidence]
    • H2: [Second most likely] — because [evidence]
    • H3: [Less likely] — because [evidence]
  5. Test Hypotheses — For each hypothesis:

    • Read the specific code that would cause this
    • Check if conditions for the bug exist
    • Look for confirming/disconfirming evidence
    • Use Bash to run diagnostic commands if helpful
  6. Identify Root Cause — Pin down:

    • Exact file:line where the bug originates
    • Why it happens (logic error, wrong assumption, missing check, race condition)
    • Why it wasn't caught (missing test, edge case, environment difference)
  7. Recommend Fix — Provide:

    • The minimal code change to fix the bug
    • Why this fix addresses the root cause (not just the symptom)
    • What test would prevent regression

Read the full file on GitHub · 127 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 · 127 lines · 87 tokens per session scan A 2f4bb9155b49

Subscribe to this mod's changes

debugger is an agent published in the GitHub repository billbuchanan-code/claude-code-power-setup (2 stars, last pushed 29d ago), licensed MIT. It adds 87 tokens to every session and 1,154 once invoked, about $0.0004 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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