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 skills add ralfyishere/rules-with-receipts --skill failure-mode-awarenessgit clone --depth 1 https://github.com/ralfyishere/rules-with-receiptsWrote 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/ralfyishere/rules-with-receipts/failure-mode-awareness)<a href="https://agentmods.dev/skills/ralfyishere/rules-with-receipts/failure-mode-awareness"><img src="https://agentmods.dev/badge/skills/ralfyishere/rules-with-receipts/failure-mode-awareness/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/ralfyishere/rules-with-receipts/failure-mode-awareness"><img src="https://agentmods.dev/badge/skills/ralfyishere/rules-with-receipts/failure-mode-awareness.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00109 | $0.01447 |
| Opus 5 | $0.00055 | $0.00724 |
| Sonnet 5 | $0.00022 | $0.00289 |
| Haiku 4.5 | $0.00011 | $0.00145 |
Grade A, and why
Failure Mode Awareness 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 12d 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 — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Failure Mode Awareness
Purpose
Cheap foresight beats expensive hindsight. Most failures aren't exotic — they're standard, catalogued, and visible in advance to anyone who asks "how does this break?" before asking "how does this work?" This skill runs that question early, when changing course costs a sentence instead of a rewrite.
When to use this skill
- At plan time (
plan-gaterisk section) and design time — before the approach hardens. - Before recommending a course of action the user will invest in.
- When reviewing someone else's plan, proposal, or idea.
- Before shipping anything with real blast radius: data migrations, external sends, public artifacts.
When NOT to use this skill
- On finished work — that's
adversarial-verify's job (attack the artifact, not the idea). - On low-stakes, reversible tasks. Enumerating failure modes for a typo fix is noise.
- As a reason not to act: the output is mitigations and watch-items, not paralysis.
Operating procedure
Step 1 — Run the premortem. "It's three months later and this failed. What's the most boring, most likely reason?" Write down the top 2–3. The boring qualifier matters: real failures are usually mundane (nobody used it, the data was dirty, the dependency changed), not dramatic.
Step 2 — Sweep the relevant catalog (pick the sections that apply):
Software failures
- Edge inputs: empty, null, zero, negative, huge, duplicate, malformed, unicode.
- State: concurrent access, partial failure mid-operation, retries causing double-execution, stale caches.
- Integration: the other system is down, slow, rate-limiting, or returns a shape you didn't expect.
- Environment: works locally, differs in prod (versions, permissions, paths, env vars, clock, locale).
- Scale and time: fine at 10 rows, dead at 10 million; fine today, broken at month-end/DST/leap year.
Reasoning failures
- Anchoring on the first hypothesis; confirmation bias in which evidence gets collected.
- Survivorship bias (studying only what succeeded); base-rate neglect ("this time is different").
- Extrapolating from an unrepresentative sample; correlation read as cause.
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.
- 12d ago First seen · 93 lines · 0 tokens per session scan A 40b4ed3bb3d4
Failure Mode Awareness is a skill published in the GitHub repository ralfyishere/rules-with-receipts (2 stars, last pushed 2mo ago), licensed MIT. It adds 109 tokens to every session and 1,447 once invoked, about $0.0005 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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