failure-analysis

failure-analysis is a skill for Claude Code from CassioRoos/godfly-skills. It costs 92 tokens per session (1,310 once invoked), scanned A, original, MIT.

A structured way to identify and rank how code, architecture, or systems can fail. It uses Failure Mode and Effects Analysis, a method for rating specific failures by impact, likelihood, and how easily they would be detected.

In plain words
What is it for?
Use it during architecture reviews, critical error-handling reviews, infrastructure or deployment changes, and decisions such as data migrations or public API changes.
Why use it?
It turns vague worries into concrete failure cases with priorities and possible mitigations.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it during architecture reviews, critical error-handling reviews, infrastructure or deployment changes, and decisions such as data migrations or public API changes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cassioroos/godfly-skills/failure-analysis
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.

Any agent
npx skills add CassioRoos/godfly-skills --skill failure-analysis
Clone the repo
git clone --depth 1 https://github.com/CassioRoos/godfly-skills

Made for: Claude Code.

Wrote 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.

agentmods badge for failure-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/cassioroos/godfly-skills/failure-analysis.svg)](https://agentmods.dev/skills/cassioroos/godfly-skills/failure-analysis)
Your own site
<a href="https://agentmods.dev/skills/cassioroos/godfly-skills/failure-analysis"><img src="https://agentmods.dev/badge/skills/cassioroos/godfly-skills/failure-analysis.svg" alt="Measured on agentmods" height="20"></a>
Per session 92 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,310 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00092 $0.01310
Opus 5 $0.00046 $0.00655
Sonnet 5 $0.00018 $0.00262
Haiku 4.5 $0.00009 $0.00131

Measured 7d ago against content hash f77f56d5d344, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

failure-analysis 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 7d 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.

skills/failure-analysis/SKILL.md · 140 lines

How it starts

The opening of the file, as written. The whole thing — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Failure Analysis

Don't ask "what could go wrong?" -- that's too vague. Ask "what SPECIFICALLY fails, how bad is it, and would you even notice?"

Core Principle

Shallow failure analysis produces a list of scary-sounding risks. Structured failure analysis produces a prioritized list of specific failure modes with severity, probability, detectability, and mitigation. The difference is actionable vs. anxiety-inducing.

When to Use

  • Reviewing architecture before implementation
  • Evaluating error handling in critical paths
  • Assessing infrastructure and deployment changes
  • Before irreversible decisions (data migrations, public API contracts)
  • When someone says "that won't happen" without analysis

Technique 1: FMEA (Failure Mode and Effects Analysis)

For each component or decision point:

Step 1: Identify Failure Modes

What can go wrong? Be specific -- not "the database fails" but "write timeout on the invoices table during peak load when batch processing overlaps with API traffic."

Step 2: Rate Each Failure Mode

Factor Scale Question
Severity 1-10 How bad is the impact when this fails?
Probability 1-10 How likely is this to happen?
Detectability 1-10 How hard is it to NOTICE this failure? (10 = silent failure)

Risk Priority Number (RPN) = Severity x Probability x Detectability

RPN Range Priority Action
200+ Critical Must address before shipping
100-199 High Should address, or add monitoring
50-99 Medium Document and monitor
<50 Low Accept the risk

Step 3: Focus on Silent Failures

The most dangerous failures are the ones with HIGH Detectability scores -- failures you won't notice until the damage is done. Prioritize these over dramatic but obvious failures.

A database going down is loud. Data being silently corrupted for weeks is catastrophic.

Technique 2: Dependency Chain Analysis

Read the full file on GitHub · 140 lines

Files

What ships with it

3 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.

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. 7d ago First seen · 140 lines · 92 tokens per session scan A f77f56d5d344

Subscribe to this mod's changes

failure-analysis is a skill published in the GitHub repository CassioRoos/godfly-skills (1 stars, last pushed 7d ago), licensed MIT. It adds 92 tokens to every session and 1,310 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.