rtfm

rtfm is a skill for Claude Code, Codex from Kevin-Liu-01/Agent-Machines. It costs 43 tokens per session (602 once invoked), scanned A, original, MIT.

A verification-first practice for checking programming and documentation claims against primary sources. It means reading the actual API, source code, command output, or official documentation before relying on an assumption.

In plain words
What is it for?
Use it when choosing an implementation, checking an API parameter, confirming a limitation, or writing code and docs that depend on a library or service.
Why use it?
It reduces errors caused by guessing about what a tool supports or how it behaves. This helps prevent unnecessary workarounds and incorrect instructions.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when choosing an implementation, checking an API parameter, confirming a limitation, or writing code and docs that depend on a library or service.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kevin-liu-01/agent-machines/rtfm
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 Kevin-Liu-01/Agent-Machines --skill rtfm
Clone the repo
git clone --depth 1 https://github.com/Kevin-Liu-01/Agent-Machines

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 rtfm

README.md
[![agentmods](https://agentmods.dev/badge/skills/kevin-liu-01/agent-machines/rtfm/github.svg)](https://agentmods.dev/skills/kevin-liu-01/agent-machines/rtfm)
Your own site
<a href="https://agentmods.dev/skills/kevin-liu-01/agent-machines/rtfm"><img src="https://agentmods.dev/badge/skills/kevin-liu-01/agent-machines/rtfm/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 rtfm

Your own site · 80×15
<a href="https://agentmods.dev/skills/kevin-liu-01/agent-machines/rtfm"><img src="https://agentmods.dev/badge/skills/kevin-liu-01/agent-machines/rtfm.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 602 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 $0.00043 $0.00602
Opus 5 $0.00022 $0.00301
Sonnet 5 $0.00009 $0.00120
Haiku 4.5 $0.00004 $0.00060

Measured 9d ago against content hash 3c0e3937cf9b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

rtfm 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 9d 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.

knowledge/skills/rtfm/SKILL.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

RTFM

When you think you know how an API, tool, or system works, you are wrong until you have verified it against the source. This skill exists because workarounds for nonexistent limitations are worse than the problems they claim to solve.

When to use

Every time you:

  • claim a library, API, or tool lacks a feature
  • claim something "can't be done" or "isn't supported"
  • write a workaround, shim, or fallback
  • choose one approach over another based on a tool's capabilities
  • dismiss an option without trying it

Procedure

1. Read the primary source

The actual code, API docs, or type signature. Not a summary. Not a blog post. Not your memory.

Claim type Where to look
"crate X doesn't support Y" docs.rs/X, GitHub source, Cargo.toml features
"API doesn't accept parameter Z" OpenAPI spec, SDK type definition, --help
"kernel doesn't support mode M" kernel.org/doc/html/, Documentation/ tree
"service doesn't offer feature F" official product docs, changelog, pricing page
"protocol doesn't allow operation O" RFC, spec PDF, reference implementation

2. Read the secondary source

Official examples, changelogs, migration guides.

  • README examples in the upstream repo
  • CHANGELOG entries for the version you are using
  • Official SDK example repos
  • Release notes and migration guides

3. Read the tertiary source

Community evidence that people are doing the thing you think is impossible.

  • GitHub issues and PRs mentioning the feature
  • Stack Overflow answers with working code
  • Reddit or HN threads with first-hand experience
  • Conference talks or blog posts from maintainers

4. Run it

If the claim is about runtime behavior, write a minimal test. Five lines. Compile it. Run it. See what happens. Do not theorize about what the compiler, runtime, or service will do. Ask it.

5. Only then decide

After steps 1-4, you may say "X doesn't support Y." Not before.

If you skipped any step, go back. The five minutes you spend reading docs saves the five hours you spend building and debugging a workaround for a limitation that does not exist.

Read the full file on GitHub · 78 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. 9d ago First seen · 78 lines · 43 tokens per session scan A 3c0e3937cf9b

Subscribe to this mod's changes

rtfm is a skill published in the GitHub repository Kevin-Liu-01/Agent-Machines (29 stars, last pushed today), licensed MIT. It adds 43 tokens to every session and 602 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 2026-09-03.

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