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/aethrox/doctrine/diagnosing-bugsnpx skills add aethrox/doctrine --skill diagnosing-bugsgit clone --depth 1 https://github.com/aethrox/doctrineWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/aethrox/doctrine/diagnosing-bugs)<a href="https://agentmods.dev/skills/aethrox/doctrine/diagnosing-bugs"><img src="https://agentmods.dev/badge/skills/aethrox/doctrine/diagnosing-bugs.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00083 | $0.01223 |
| Opus 5 | $0.00042 | $0.00611 |
| Sonnet 5 | $0.00017 | $0.00245 |
| Haiku 4.5 | $0.00008 | $0.00122 |
Grade A, and why
diagnosing-bugs 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 6d 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 — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Diagnosing Bugs
Debugging is not guessing with extra steps; it's a search problem, and a search problem has a systematic solution: understand the space you're searching, reproduce the failure on demand, shrink the search space by half at a time, and change exactly one thing per experiment so cause and effect stay unambiguous. Every rule below traces back to Agans' Debugging: The 9 Indispensable Rules; treat them as a sequence, not a menu to pick from.
Redact secrets before showing any command, log, or captured artifact: same discipline as secure-coding's Phase 3: replace credentials with <REDACTED>, quote only the lines carrying real signal from anything with auth headers or full payloads.
Rule 1: Understand the system
Before touching anything, know the normal path the failing code should take: read CONTEXT.md or equivalent domain docs if they exist, trace the flow from entry point to the point of failure, and know what "correct" looks like well enough to recognize it. A theory formed without this is a guess with the system's real shape substituted by an assumed one.
Rule 2: Make it fail, then look before you theorize
Reproduce on demand first. A bug that only happens "sometimes, somewhere in prod" isn't diagnosable yet; build the smallest repeatable trigger: a failing test, a script, a request replayed against a dev instance. For a flaky/non-deterministic failure, the goal isn't a clean 100% repro but a high enough reproduction rate to observe: loop it, add stress, narrow timing windows, until it fails often enough to study.
Then look, don't theorize. With a reproducible failure in hand, inspect the actual evidence (logs, state, a debugger breakpoint) before forming a hypothesis. A theory built by staring at code without first looking at what the system actually did is the single most common way to burn time chasing the wrong cause.
Rule 3: Divide and conquer
Shrink the suspect region by bisecting it, not by scanning it linearly:
What ships with it
1 file 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.
- 6d ago First seen · 58 lines · 83 tokens per session scan A afdcb7f70093
diagnosing-bugs is a skill published in the GitHub repository aethrox/doctrine (18 stars, last pushed 25d ago), licensed MIT. It adds 83 tokens to every session and 1,223 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 2026-08-30.
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