debugging

A structured method for finding the root cause of errors, failed tests, unexpected behavior, and performance problems. It uses evidence such as logs, stack traces, and repeatable steps.

In plain words
What is it for?
Investigate exceptions and test failures, reproduce issues, isolate the responsible code, apply small fixes, and verify the result.
Why use it?
It replaces guesswork with a process for isolating the failure, testing possible explanations, and checking that the fix causes no new problems.

Skill for Claude CodeCodex

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 skills/siviter-xyz/dot-agent/debugging
Any agent
npx skills add siviter-xyz/dot-agent --skill debugging
Clone the repo
git clone --depth 1 https://github.com/siviter-xyz/dot-agent

Made for: Claude Code, Codex.

Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 443 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 $0.00032 $0.00443
Opus 5 $0.00016 $0.00221
Sonnet 5 $0.00006 $0.00089
Haiku 4.5 $0.00003 $0.00044

Measured 3d ago against content hash b15ec92df510, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debugging 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 3d 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.

skills/debugging/SKILL.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debugging

Systematic approach to root cause analysis and debugging.

When to Use

  • Encountering errors or exceptions
  • Test failures that need investigation
  • Unexpected behavior in code
  • Stack traces or error messages
  • Code behaving differently than expected
  • Performance issues or bugs

Core Principles

  • Evidence-based: Base diagnosis on error messages, logs, and reproducible steps
  • Systematic: Follow structured debugging process
  • Minimal fixes: Implement smallest change that resolves issue
  • Verify solutions: Confirm fix works and doesn't introduce regressions

Debugging Process

Follow systematic debugging process:

  1. Capture error information (message, stack trace, logs, environment)
  2. Identify reproduction steps (minimal steps, conditions, edge cases)
  3. Isolate failure location (function/module, recent changes, dependencies)
  4. Form and test hypotheses (evidence-based, systematic testing, debug logging)
  5. Implement minimal fix (smallest change, preserve behavior, follow patterns)
  6. Verify solution (issue resolved, no regressions, tests pass)

See references/root-cause-analysis.md for detailed methods.

Strategic Debug Logging

Add debug logging to entry/exit points, state transitions, conditional branches, external API calls, and data transformations. Remove after issue resolved unless it provides ongoing value.

Error Pattern Recognition

Common patterns: null/undefined errors, type errors, timing issues, state corruption, configuration issues. See references/error-patterns.md for detailed patterns and solutions.

Integration

After fixing:

  • Verify CI passes (types, tests, lint)
  • Stage atomic changes (fix + tests)
  • Suggest semantic commit message
  • Confirm with user before committing

References

For detailed guidance, see:

  • references/root-cause-analysis.md - Systematic analysis methods
  • references/error-patterns.md - Common error patterns and solutions
  • references/debugging-tools.md - Debugging tools and techniques

Read the full file on GitHub · 60 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 3d ago First seen · 60 lines · 32 tokens per session scan A b15ec92df510

Subscribe to this mod's changes

debugging is a skill published in the GitHub repository siviter-xyz/dot-agent (21 stars, last pushed 5mo ago), licensed MIT. It adds 32 tokens to every session and 443 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 2026-08-30.

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