bex: Skill for Claude Code

.claude/skills/routine-crash-fuzzer/SKILL.md

routine-crash-fuzzer is a skill for Claude Code, Codex from bex-co/bex. It costs 87 tokens per session (1,537 once invoked), scanned A, original, Apache-2.0.

A crash-finding routine that first checks service logs for real panics, crash loops, and bursts of server errors, then fuzzes Go parsers with unexpected inputs. Fuzzing means automatically trying many inputs to expose failures.

In plain words
What is it for?
Use it to investigate application crashes, test parsers that handle untrusted input, fix discovered causes, and add tests that prevent the same failures from returning.
Why use it?
It focuses on crashes already seen in running services before testing hypothetical parser failures. It also requires root-cause fixes, regression tests, and verification before shipping.

Skill for Claude CodeCodex

Written for Claude Code and Codex: $ARGUMENTS substitution, but also agents/openai.yaml present. Also seen: mentions Codex.

This is bex-co/bex's own configuration. It tells Claude Code and Codex how to work on bex itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything bex configures →

Reuse

Borrowing it

Nothing to install: this file belongs to bex-co/bex. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/bex-co/bex/main/.claude/skills/routine-crash-fuzzer/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/bex-co/bex

Made for: Claude Code, Codex.

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 routine-crash-fuzzer

README.md
[![agentmods](https://agentmods.dev/badge/skills/bex-co/bex/routine-crash-fuzzer/github.svg)](https://agentmods.dev/skills/bex-co/bex/routine-crash-fuzzer)
Your own site
<a href="https://agentmods.dev/skills/bex-co/bex/routine-crash-fuzzer"><img src="https://agentmods.dev/badge/skills/bex-co/bex/routine-crash-fuzzer/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 routine-crash-fuzzer

Your own site · 80×15
<a href="https://agentmods.dev/skills/bex-co/bex/routine-crash-fuzzer"><img src="https://agentmods.dev/badge/skills/bex-co/bex/routine-crash-fuzzer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 87 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,537 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 5 findings, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Privilege Escalation · line 34
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 35
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 36
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • high Privilege Escalation · line 35
    Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
    Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
  • medium Excessive Agency · line 15
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
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 $0.00087 $0.01537
Opus 5 $0.00044 $0.00768
Sonnet 5 $0.00017 $0.00307
Haiku 4.5 $0.00009 $0.00154

Measured 4d ago against content hash 55d04fa24bb1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

routine-crash-fuzzer 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 4d 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.

.claude/skills/routine-crash-fuzzer/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Routine: Crash Fuzzer

Find crashes from two evidence sources — live platform service logs first (real crashes beat hypothetical ones), then Go native fuzzing of untrusted-input parsers — and fix each at its root cause.

Routine ground rules

  • A user request to run this routine authorizes the full cycle: plan, fix, verify, then invoke $ship (Codex) or /ship (Claude) directly in the same run. Honor explicit user limits such as audit-only or no-ship.
  • Keep a concise execution plan in the conversation and update it as findings are confirmed. Continue into implementation without a planning approval pause. Do not create or file a .pm milestone/task as a prerequisite or substitute for fixing; use the board only if the user requests it.
  • After the verification phase, follow the shipping phase below without asking the user to invoke ship separately. Preserve the ship skill's branch, conflict-resolution, and safety rules.
  • Fix everything you find directly in the working tree. If a fix can't be finished safely in this run, revert only your partial work for that fix and list it under Deferred in the report — never leave the tree half-refactored.
  • Scope: parse $ARGUMENTS per Phase 1 — an optional path/module scope or skill-specific target. No argument = the skill's stated default (usually the whole repo via parallel agents per module: lego/types, lego/operator, lego/backend, lego/cli, dashboard).
  • False-positive discipline: if a finding is intentional, load-bearing, or ambiguous, skip it with a one-line reason — don't argue it into a change.
  • Every change must pass the verification gates for the modules it touched before being reported as done: operator make test + make lint (from lego/operator/), cd lego/backend && go test ./..., cd lego/cli && go test ./..., dashboard yarn test + typecheck.
  • Run npx [email protected] --write on any markdown touched.
  • Before shipping, summarize results in commentary using: Fixed (file:line + one-line rationale) / Deferred (item + why) / Skipped (finding + reason) / Gates (commands run + outcomes).

Read the full file on GitHub · 66 lines

Files

What ships with it

1 file 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. 4d ago First seen · 66 lines · 87 tokens per session scan A 55d04fa24bb1

Subscribe to this mod's changes

routine-crash-fuzzer is a skill published in the GitHub repository bex-co/bex (555 stars, last pushed today), licensed Apache-2.0. It adds 87 tokens to every session and 1,537 once invoked, about $0.0004 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 2026-09-05.

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