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.
npx agentmods add skills/go1c/lumioagent/systematic-debuggingnpx skills add Go1c/LumioAgent --skill systematic-debugginggit clone --depth 1 https://github.com/Go1c/LumioAgentWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00021 | $0.01200 |
| Opus 5 | $0.00010 | $0.00600 |
| Sonnet 5 | $0.00004 | $0.00240 |
| Haiku 4.5 | $0.00002 | $0.00120 |
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.
How it starts
The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Systematic Debugging
Overview
Random fixes waste time and create new bugs. Quick patches mask underlying issues.
Core principle: ALWAYS find root cause before attempting fixes. Symptom fixes are failure.
Violating the letter of this process is violating the spirit of debugging.
The Iron Law
NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST
If you haven't completed Phase 1, you cannot propose fixes.
When to Use
Any technical issue: test failures, bugs, unexpected behavior, performance problems, build failures, integration issues.
ESPECIALLY when skipping is tempting: under time pressure, "just one quick fix" seems obvious, previous fixes didn't work, or the issue seems simple. Systematic debugging is faster than guess-and-check thrashing — and simple bugs have root causes too.
The Four Phases
Complete each phase before the next.
Phase 1: Root Cause Investigation
- Read error messages carefully — full stack traces, line numbers, error codes. They often contain the exact solution.
- Reproduce consistently — exact steps, reliable trigger. Not reproducible → gather more data, don't guess.
- Check recent changes — git diff, recent commits, new dependencies, config, environment.
- Gather evidence at component boundaries (multi-component systems: CI → build → signing, API → service → DB): before proposing fixes, log what enters and exits each component, run once, and let the evidence show WHERE it breaks — then investigate that component.
- Trace data flow backward — where does the bad value originate? Keep tracing up the call stack to the source; fix at the source, not the symptom. Complete technique:
root-cause-tracing.mdin this directory.
Phase 2: Pattern Analysis
- Find similar working code in the same codebase
- Read reference implementations COMPLETELY — skimming guarantees partial understanding
- List every difference between working and broken, however small; don't assume "that can't matter"
- Understand the dependencies, config, and assumptions involved
What ships with it
5 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.
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.
- 2d ago First seen · 102 lines · 21 tokens per session scan A 96814bb5c114
systematic-debugging is a skill published in the GitHub repository Go1c/LumioAgent (20 stars, last pushed 1mo ago), licensed MIT. It adds 21 tokens to every session and 1,200 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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