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plain-forge: Instructions file for Claude Code

CLAUDE.md

plain-forge CLAUDE.md is an instructions file for Claude Code from plainlang/plain-forge. It costs 2,733 tokens per session, scanned A, a copy of plain-forge AGENTS.md, MIT.

Repository instructions for plain-forge, an npm package with a small installer and a library of instructions for AI agents that create and maintain plain specification files. It copies those files into an agent directory; a separate codeplain command-line tool renders the specifications into code.

In plain words
What is it for?
They help maintain the installer, run its Node.js tests, and edit the skills and rules stored under the forge directory.
Why use it?
They clarify the boundary between the installer and the instructional content, so developers know what to edit and understand that code generation happens elsewhere.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: mentions CLAUDE.md; mentions Claude Code; mentions AGENTS.md.

This is plainlang/plain-forge's own configuration. It tells Claude Code how to work on plain-forge 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 plain-forge configures →

not rated 106repo +26 changed 4d ago A scan 2,733 tokens copy · 100% MIT
View source ↗ plainlang/plain-forge
Reuse

Borrowing it

Nothing to install: this file belongs to plainlang/plain-forge. 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/plainlang/plain-forge/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/plainlang/plain-forge

Made for: Claude Code.

Wrote this? Show the measurements

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Per session 2,733 This file is loaded in full into every session.
When invoked 2,733 The same file — it is already loaded in full.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% 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 $0.02733 $0.02733
Opus 5.5 $0.01093 $0.01093
Sonnet 5.5 $0.00547 $0.00547
Haiku 4.5 $0.00273 $0.00273

Measured 4d ago against content hash 52f1fd00ce5d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

plain-forge CLAUDE.md 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 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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

- `test/cli.test.mjs` mixes unit tests (importing named exports from `bin/cli.mjs`) with black-box integration tests that `spawnSync` the real CLI into isolated temp `HOME`/cwd dirs.
Origin

This is a copy

100% identical to plain-forge AGENTS.md — 0 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.

CLAUDE.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

What this repo is

plain-forge is an npm package with two distinct halves:

  1. A tiny installer CLI (bin/cli.mjs) — npx plain-forge install|update|uninstall.
  2. The actual product under forge/ — a library of AI-agent skills and rules that teach an agent to author and maintain ***plain specification files. The CLI copies forge/ verbatim into an agent directory; there is no build step and no generated/committed output.

So a change here is almost always one of: (a) editing the installer CLI, or (b) editing the instructional content under forge/skills/ (the authoring rules live in forge/skills/load-plain-reference/rules/). These need different mindsets — see "Editing forge/ content" below.

plain-forge only authors .plain specs. Rendering specs into code is done by a separate renderer, which this repo does not contain.

Commands

npm test                                                   # full suite: node --test test/*.test.mjs
node --test --test-name-pattern="<regex>" test/*.test.mjs  # run a single test by name
node --test test/cli.test.mjs                              # run a single test file
  • Test runner is Node's built-in node:test (node:assert/strict) — not jest/vitest, no test framework dependency. Requires Node ≥18.
  • test/cli.test.mjs mixes unit tests (importing named exports from bin/cli.mjs) with black-box integration tests that spawnSync the real CLI into isolated temp HOME/cwd dirs.
  • Releases are cut by publishing a GitHub Release tagged vX.Y.Z, which publishes to npm via OIDC — see RELEASING.md. The version lives in the tag, so package.json on main is intentionally stale.
  • There is no working build or lint step. package.json declares build/clean scripts (tsx bin/forge-build.ts) and tsconfig.json references bin/**/*.ts + runtimes/**/*.ts, but those files do not exist — npm run build/npm run clean error out. The TS toolchain (tsx/typescript) is vestigial; the CLI is plain .mjs run directly by Node. Don't try to build.

Read the full file on GitHub · 88 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. 4d ago Changed · +43 tokens per session 52f1fd00ce5d
  2. 9d ago Changed · +9 tokens per session 5e3c4a3cc2c4
  3. 10d ago Changed · +242 tokens per session a4b5bdf84b7e
  4. 15d ago Changed · +6 lines · +158 tokens per session 4c8a7624bb91
  5. 1mo ago Changed · +88 tokens per session ae9765feeafb
  6. 2mo ago First seen · 82 lines · 2,193 tokens per session scan A a33dbbe706f5

Subscribe to this mod's changes

plain-forge CLAUDE.md is an instructions file published in the GitHub repository plainlang/plain-forge (106 stars, last pushed yesterday), licensed MIT. It adds 2,733 tokens to every session, about $0.0109 per session on Opus 5.5. A static security scan graded it A with 1 finding (runs shell commands). It is 100% identical to plain-forge AGENTS.md, differing in 0 lines, and is treated as a copy.

Related

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