systematic-debugging

A four-phase method for debugging: reproduce the problem, find its cause, fix it, and verify the result.

In plain words
What is it for?
Use it for unexpected behavior, failing tests, production problems, and performance issues.
Why use it?
It replaces guesswork with a repeatable process and records the conditions and evidence behind a bug.

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/freepeak/ktme/systematic-debugging
Any agent
npx skills add FreePeak/ktme --skill systematic-debugging
Clone the repo
git clone --depth 1 https://github.com/FreePeak/ktme

Made for: Claude Code, Codex.

Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,751 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 $0.00023 $0.01751
Opus 5 $0.00012 $0.00875
Sonnet 5 $0.00005 $0.00350
Haiku 4.5 $0.00002 $0.00175

Measured 2d ago against content hash f36c77e03602, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

systematic-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 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.

.kilo/skills/systematic-debugging/SKILL.md · 320 lines

How it starts

The opening of the file, as written. The whole thing — 320 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Systematic Debugging

A structured approach to debugging that ensures consistent, reliable bug fixes with verification.

When to Use

Use this skill when:

  • Encountering unexpected behavior or errors
  • Investigating failing tests
  • Debugging production issues
  • Analyzing performance problems

The 4-Phase Framework

Phase 1: Reproduce the Issue

Goal: Create a minimal, reliable reproduction

Steps:

  1. Identify the exact conditions that trigger the issue
  2. Create a minimal test case or script
  3. Verify you can reproduce it consistently
  4. Document the reproduction steps

Evidence Format:

REPRODUCTION:
Environment: [OS, runtime version, dependencies]
Steps:
1. [step 1]
2. [step 2]
3. [step 3]
Expected: [what should happen]
Actual: [what actually happens]

Best Practices:

  • Isolate the problem - remove unrelated code
  • Use logging/debugging to narrow scope
  • Check if issue is deterministic or intermittent
  • Note any error messages, stack traces, or logs

Phase 2: Analyze Root Cause

Goal: Identify why the issue occurs

Steps:

  1. Trace execution flow from reproduction
  2. Examine relevant code with file:line references
  3. Identify the specific line/condition causing the issue
  4. Determine the underlying cause

Analysis Template:

ANALYSIS:
file:line - [description of problematic code]
ACTUAL: [what the code does]
EXPECTED: [what it should do]
ROOT CAUSE: [wrong input | wrong order | missing dep | config | logic | external]

EVIDENCE:
- [evidence point 1 with file:line]
- [evidence point 2 with file:line]
- [evidence point 3 with file:line]

Investigation Techniques:

  • Binary search (comment out code to isolate)
  • Check recent changes (git blame, git log)
  • Compare with working version
  • Review documentation/API specs
  • Check for race conditions/timing issues
  • Verify assumptions with assertions

Phase 3: Implement Fix

Goal: Apply minimal, targeted fix

Steps:

  1. Design the simplest possible fix
  2. Implement the fix with minimal changes
  3. Consider edge cases
  4. Add/update tests if applicable

Read the full file on GitHub · 320 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 · 320 lines · 23 tokens per session scan A f36c77e03602

Subscribe to this mod's changes

systematic-debugging is a skill published in the GitHub repository FreePeak/ktme (15 stars, last pushed 5mo ago), licensed MIT. It adds 23 tokens to every session and 1,751 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 2026-08-30.

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