bug-magnet-data

bug-magnet-data is a skill for Claude Code from ashaykubal/essential-agents-skills. It costs 38 tokens per session (2,714 once invoked), scanned A, a copy of bug-magnet-data, MIT.

A curated collection of unusual and boundary-focused test data for checking how software handles difficult inputs. Boundary testing checks values at or near limits, such as empty, maximum, or just-over-the-limit values.

In plain words
What is it for?
Use it to find missing edge-case coverage, add boundary inputs to verification scripts, or test whether a fix works under difficult conditions.
Why use it?
It provides carefully chosen cases that can expose bugs more directly than generating many random inputs.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Good fit Use it to find missing edge-case coverage, add boundary inputs to verification scripts, or test whether a fix works under difficult conditions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ashaykubal/essential-agents-skills/bug-magnet-data
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 ashaykubal/essential-agents-skills --skill bug-magnet-data
Clone the repo
git clone --depth 1 https://github.com/ashaykubal/essential-agents-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 bug-magnet-data

README.md
[![agentmods](https://agentmods.dev/badge/skills/ashaykubal/essential-agents-skills/bug-magnet-data/github.svg)](https://agentmods.dev/skills/ashaykubal/essential-agents-skills/bug-magnet-data)
Your own site
<a href="https://agentmods.dev/skills/ashaykubal/essential-agents-skills/bug-magnet-data"><img src="https://agentmods.dev/badge/skills/ashaykubal/essential-agents-skills/bug-magnet-data/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 bug-magnet-data

Your own site · 80×15
<a href="https://agentmods.dev/skills/ashaykubal/essential-agents-skills/bug-magnet-data"><img src="https://agentmods.dev/badge/skills/ashaykubal/essential-agents-skills/bug-magnet-data.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,714 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 98% copy Near-identical to another mod 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 $0.00038 $0.02714
Opus 5 $0.00019 $0.01357
Sonnet 5 $0.00008 $0.00543
Haiku 4.5 $0.00004 $0.00271

Measured 11d ago against content hash 31baf3e79600, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

bug-magnet-data 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.

Origin

This is a copy

98% identical to bug-magnet-data — 573 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/bug-magnet-data/SKILL.md · 285 lines

How it starts

The opening of the file, as written. The whole thing — 285 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bug Magnet Data

Curated edge case test data for boundary testing, verification scripts, and test generation. 50+ years of testing wisdom distilled into small, high-signal collections organized by data type.

Core Principle: Curation beats generation. 50 well-chosen edge cases find more bugs than 10,000 random inputs.


When to Use This Skill

Load this skill when the consumer request matches ANY of these patterns:

Consumer Trigger Usage
test-audit Step 7 (edge case gap detection) Identify missing boundary test coverage
bulwark-verify Generating verification scripts Inject edge cases into test scenarios
bulwark-fix-validator Validating a fix Test fix against boundary conditions

DO NOT use for:

  • Encrypted/compressed data (edge cases won't penetrate wrapping)
  • Pure unit tests with fully mocked dependencies (edge cases need real execution)
  • Performance/load testing (use dedicated load testing tools)

Pre-Flight Gate (BLOCKING)

STOP. Before providing ANY edge case data, you MUST follow the three-phase workflow.

This skill provides curated data through a deterministic workflow. You must execute all phases.

What You MUST Do

  1. Phase 1: Component Detection - Identify component type and load context file
  2. Phase 2: Data Loading - Load T0 + T1 data files (REQUIRED), T2 if specified by context
  3. Phase 3: Edge Case Application - Apply edge cases and report what was loaded

What You MUST NOT Do

  • Do NOT generate edge cases from your own knowledge - use the curated data files
  • Do NOT skip loading context files - they determine which categories apply
  • Do NOT skip the safety filter - patterns marked safe_for_automation: false must be excluded
  • Do NOT return partial data - all applicable tiers must be loaded

Why This Matters

The curated data exists because:

  • Curation beats generation - 50 well-chosen edge cases find more bugs than 10,000 random inputs
  • Reproducibility - Same component type = same edge cases every time
  • Safety - Destructive patterns are explicitly marked and filtered

Read the full file on GitHub · 285 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 · 285 lines · 38 tokens per session scan A 31baf3e79600

Subscribe to this mod's changes

bug-magnet-data is a skill published in the GitHub repository ashaykubal/essential-agents-skills (2 stars, last pushed 1mo ago), licensed MIT. It adds 38 tokens to every session and 2,714 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to bug-magnet-data, differing in 573 lines, and is treated as a copy.

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