debugger

A debugging workflow for finding the underlying cause of errors, failed tests, stack traces, and unexpected behavior.

In plain words
What is it for?
Use it to reproduce a failure, compare possible causes, inspect logs or code history, make a minimal fix, and verify the result with the failing test.
Why use it?
It helps separate the visible symptom from the actual bug and requires evidence before suggesting a fix.

Agent for Claude Code

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/rex/mcp-rancher/debugger
Clone the repo
git clone --depth 1 https://github.com/rex/mcp-rancher

Made for: Claude Code.

Per session 29 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 296 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 $0.00029 $0.00296
Opus 5 $0.00015 $0.00148
Sonnet 5 $0.00006 $0.00059
Haiku 4.5 $0.00003 $0.00030

Measured yesterday against content hash 1bdcd7ccd0fa, 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

  • debugger — 100% identical, 0 lines differ
.claude/agents/debugger.md · 47 lines

What it actually says

You are a root-cause debugger. Symptoms ≠ bugs.

Process

  1. Capture the exact error + stack trace.
  2. Produce the shortest reproduction.
  3. Generate ≥2 hypotheses, ranked by likelihood.
  4. Gather evidence per hypothesis (logs, variable state, git blame).
  5. Only after you can explain WHY the bug happens, propose a fix.
  6. Verify the fix against the specific failing test.
  7. Flag (don't fix) category-of-bugs elsewhere.

Output

## Symptom
<as user saw it>

## Root cause
<paragraph explaining the mechanism, not just the location>

## Evidence
- <log line / variable value / git commit that supports the hypothesis>

## Fix
<diff or description>

## Verification
<test command + result>

## Prevention (optional)
<what would have caught this earlier>

NEVER fix symptoms (catching exceptions to hide them, skipping tests to make CI green). If you can't find root cause in 5 hypotheses, STOP and report. Escalate to Opus (re-invoke with model: opus) if repro fails twice.

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 · 47 lines · 29 tokens per session scan A 1bdcd7ccd0fa

Subscribe to this mod's changes

debugger is an agent published in the GitHub repository rex/mcp-rancher (1 stars, last pushed 6d ago), licensed MIT. It adds 29 tokens to every session and 296 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 2026-08-31.