log-gotcha

A rule for recording newly discovered technical problems or surprising behavior in a repository wiki before handing work to a reviewer.

In plain words
What is it for?
Use it after finding a non-obvious runtime, framework, workflow, or repository issue that future contributors should know about.
Why use it?
It prevents later agents from repeating the same mistake. The rule focuses entries on real gotchas, such as flaky tests, hidden library behavior, or cross-file dependencies.

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/doidor/agentrig/log-gotcha
Any agent
npx skills add doidor/agentrig --skill log-gotcha
Clone the repo
git clone --depth 1 https://github.com/doidor/agentrig

Made for: Claude Code, Codex.

Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 857 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 $0.00040 $0.00857
Opus 5 $0.00020 $0.00428
Sonnet 5 $0.00008 $0.00171
Haiku 4.5 $0.00004 $0.00086

Measured 2d ago against content hash de432c5255d8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

log-gotcha 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.

.agents/skills/log-gotcha/SKILL.md · 69 lines

How it starts

The opening of the file, as written. The whole thing — 69 lines — stays where its author put it; the contents beside it link to each section on GitHub.

log-gotcha (principle 8)

Every mistake is a prompt bug. The wiki is how the harness learns: every entry there is one agent-turn the next agent skips because they already know what you discovered. Logging is part of the task, not a separate "good-to-have" step.

When to log

You should log a gotcha if any of these apply to what you just did:

  • A test, framework, or runtime did something surprising (e.g. divide(1, 0) returns Infinity not throws; node --test some-dir resolves the dir as a module; console.log after process.exit silently truncates piped output).
  • A library default bit you (silent overwrite, surprising coercion, hidden API contract).
  • An AGENTS.md rule wasn't loud enough — you almost violated it, or did, until you caught yourself.
  • A non-obvious cross-file dependency that someone touching one file would miss.
  • A flaky test, an environment-specific assumption, a build-cache surprise.

Do not log taste opinions, style preferences, or things that are already in CONTRIBUTING.md.

How to log

  1. Check the wiki first. Run ls .agents/wiki/ and grep -ri "<keyword>" .agents/wiki/ for the most natural keywords. If an existing entry covers it, SHARPEN that entry instead of adding a near-duplicate (the wiki README has a strict admission test on duplication).
  2. Pick a topic file. Either an existing one (e.g. troubleshooting.md) or create .agents/wiki/<topic>.md if the area is new (e.g. node-test-runner.md, html-templates.md). Topic names are kebab-case nouns.
  3. Write a stub entry using the template below. Keep it terse — 5 lines max.
  4. Commit it as part of your fix's diff. Wiki entries are not "after-the-fact paperwork" — they go in the SAME commit/PR as the fix that revealed them, so reviewers can see them.

Entry template

### <short noun-phrase title>
- **Symptom:** what went wrong / how it showed up
- **Cause:** the real root cause (not the symptom)
- **Fix:** the change you made (or wider remediation)
- **Prevention:** one-line rule that would have spared you this discovery
- **Discovered:** <date> in <scenario or task id>

Read the full file on GitHub · 69 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 · 69 lines · 40 tokens per session scan A de432c5255d8

Subscribe to this mod's changes

log-gotcha is a skill published in the GitHub repository doidor/agentrig (5 stars, last pushed 1mo ago), licensed MIT. It adds 40 tokens to every session and 857 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 2026-08-31.

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