billy

An investigation skill for checking whether a technical claim is true. It gathers evidence from commands, logs, code, or APIs and reports what the evidence shows.

In plain words
What is it for?
Use it to investigate claims such as a stopped service, a failing endpoint, a production migration problem, or a memory leak.
Why use it?
It replaces assumptions about failures or incidents with verified findings, without changing the system under investigation.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/lexfrei/ccc/billy
Any agent
npx skills add lexfrei/ccc --skill billy
Clone the repo
git clone --depth 1 https://github.com/lexfrei/ccc

Made for: Claude Code, Codex.

Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 751 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
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 $0.00020 $0.00751
Opus 5 $0.00010 $0.00376
Sonnet 5 $0.00004 $0.00150
Haiku 4.5 $0.00002 $0.00075

Measured 2d ago against content hash 8c5a1c5f99de, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

billy scanned grade A with 1 finding 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 2d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- **Network**: `curl` endpoints, check connectivity, DNS resolution, port availability
skills/billy/skills/billy/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Where's the proof, Billy? We need proof!

Someone made a claim. Stop everything and investigate. No proof — no trust.

Input

The argument is a claim that needs verification. Examples:

  • /billy "the runner is dead"
  • /billy "this endpoint returns 500 on empty body"
  • /billy "the migration broke prod"
  • /billy "node memory is leaking"

Rules

  1. Do NOT take the claim at face value. Assume nothing. Verify everything.
  2. Do NOT stop at the first piece of evidence. Keep digging until you have a conclusive answer.
  3. Do NOT suggest — investigate. Run commands, read logs, check code, query APIs. Produce evidence.
  4. Do NOT fix anything. This is investigation only. Report findings, never apply changes.

Process

Launch an Agent (model: opus) to perform the investigation. The agent must:

Phase 1: Understand the claim

Parse the assertion. Identify:

  • Subject: what system/component/process is involved
  • Predicate: what is being claimed about it (dead, broken, leaking, failing, etc.)
  • Implicit scope: timeframe, environment, context from the current conversation

Phase 2: Gather evidence

Use every available tool to collect evidence. Prioritize direct observation over inference:

  • Processes and services: ps, systemctl status, docker ps, kubectl get pods, health endpoints
  • Logs: application logs, system logs, journal, container logs, dmesg
  • Code and config: read source code, check recent changes (git log, git diff), review config files
  • Network: curl endpoints, check connectivity, DNS resolution, port availability
  • Resources: disk space, memory, CPU, file descriptors, connection pools
  • External systems: CI/CD status (gh run list), monitoring dashboards, database state
  • History: git blame, recent deploys, recent config changes, cron jobs

Collect at least 3 independent pieces of evidence before forming a conclusion.

Phase 3: Attempt to reproduce

If the claim describes a failure or behavior:

Read the full file on GitHub · 97 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. 2d ago First seen · 97 lines · 0 tokens per session scan A 8c5a1c5f99de

Subscribe to this mod's changes

billy is a skill published in the GitHub repository lexfrei/ccc (9 stars, last pushed 2d ago), licensed BSD-3-Clause. It adds 20 tokens to every session and 751 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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