silent-failure-hunter

silent-failure-hunter is a skill for Claude Code from euxx/claude-skills-for-copilot. It costs 44 tokens per session (624 once invoked), scanned A, original, MIT.

An audit of error-handling code that looks for failures hidden from users, unclear messages, overly broad catches, and unjustified fallbacks.

In plain words
What is it for?
Reviewing try/catch blocks, error callbacks, fallback logic, and failure-related branches after error handling has been changed.
Why use it?
It helps prevent errors from being swallowed or replaced with behavior that hides the real problem.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Good fit Reviewing try/catch blocks, error callbacks, fallback logic, and failure-related branches after error handling has been changed.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/euxx/claude-skills-for-copilot/silent-failure-hunter
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 euxx/claude-skills-for-copilot --skill silent-failure-hunter
Clone the repo
git clone --depth 1 https://github.com/euxx/claude-skills-for-copilot

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 silent-failure-hunter

README.md
[![agentmods](https://agentmods.dev/badge/skills/euxx/claude-skills-for-copilot/silent-failure-hunter/github.svg)](https://agentmods.dev/skills/euxx/claude-skills-for-copilot/silent-failure-hunter)
Your own site
<a href="https://agentmods.dev/skills/euxx/claude-skills-for-copilot/silent-failure-hunter"><img src="https://agentmods.dev/badge/skills/euxx/claude-skills-for-copilot/silent-failure-hunter/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.

agentmods 80×15 button for silent-failure-hunter

Your own site · 80×15
<a href="https://agentmods.dev/skills/euxx/claude-skills-for-copilot/silent-failure-hunter"><img src="https://agentmods.dev/badge/skills/euxx/claude-skills-for-copilot/silent-failure-hunter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 624 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 $0.00044 $0.00624
Opus 5 $0.00022 $0.00312
Sonnet 5 $0.00009 $0.00125
Haiku 4.5 $0.00004 $0.00062

Measured 11d ago against content hash fb57691f0340, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

silent-failure-hunter 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 11d 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/silent-failure-hunter/SKILL.md · 62 lines

How it starts

The opening of the file, as written. The whole thing — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Silent Failure Hunter

Audit error handling code for silent failures, inadequate user feedback, and unjustified fallback behavior. Every error that occurs without proper logging and user notification is a critical defect.

Core Principles (non-negotiable)

  1. Silent failures are unacceptable — any error without proper logging and user notification is a critical defect.
  2. Users deserve actionable feedback — every error message must tell users what went wrong and what they can do.
  3. Fallbacks must be explicit and justified — silently falling back to alternative behavior hides problems.
  4. Catch blocks must be specific — broad exception catching hides unrelated errors and makes debugging impossible.
  5. Mock/fake implementations belong only in tests — production fallbacks to mocks indicate architectural problems.

Review Process

1. Identify All Error Handling Code

Systematically locate:

  • All try/catch blocks
  • All error callbacks and error event handlers
  • All conditional branches that handle error states
  • All fallback logic and default values used on failure
  • Optional chaining (?.) used in error handlers or callbacks where errors should be explicitly handled (not general null-safe property access)

2. Scrutinize Each Error Handler

For every error handling location:

Logging quality: Is the error logged with appropriate severity and context? Would this log help debug the issue months from now?

User feedback: Does the user receive clear, actionable feedback? Is the error message specific enough to be useful?

Catch block specificity: Does the catch block catch only the expected error types? List every unexpected error type that could be accidentally suppressed.

Fallback behavior: Is the fallback explicitly justified? Does it mask the underlying problem? Would the user be confused by the fallback rather than seeing an error?

Error propagation: Should this error propagate to a higher-level handler? Is it being swallowed when it should bubble up?

Read the full file on GitHub · 62 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. 11d ago First seen · 62 lines · 44 tokens per session scan A fb57691f0340

Subscribe to this mod's changes

silent-failure-hunter is a skill published in the GitHub repository euxx/claude-skills-for-copilot (4 stars, last pushed 2mo ago), licensed MIT. It adds 44 tokens to every session and 624 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.