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composer-plugin: Instructions file for Codex

AGENTS.md

composer-plugin AGENTS.md is an instructions file for Codex, OpenCode from hyperactdoting/composer-plugin. It costs 439 tokens per session, scanned A, original, MIT.

Instructions for using Composer, a real-time collaborative markdown editor, with a terminal coding agent.

In plain words
What is it for?
Use them when joining Composer rooms, monitoring shared documents, replying to comments, or posting anchored suggestions.
Why use it?
They explain how to open shared documents, handle comments and mentions, and collaborate without guessing the editor's conventions.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions subagents.

This is hyperactdoting/composer-plugin's own configuration. It tells Codex and OpenCode how to work on composer-plugin 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 composer-plugin configures →

not rated 2repo 4mo ago A scan 439 tokens original MIT
View source ↗ hyperactdoting/composer-plugin usecomposer.app
Reuse

Borrowing it

Nothing to install: this file belongs to hyperactdoting/composer-plugin. 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/hyperactdoting/composer-plugin/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/hyperactdoting/composer-plugin

Made for: Codex, OpenCode.

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 composer-plugin AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/hyperactdoting/composer-plugin/agents-md/github.svg)](https://agentmods.dev/instructions/hyperactdoting/composer-plugin/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/hyperactdoting/composer-plugin/agents-md"><img src="https://agentmods.dev/badge/instructions/hyperactdoting/composer-plugin/agents-md/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 composer-plugin AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/hyperactdoting/composer-plugin/agents-md"><img src="https://agentmods.dev/badge/instructions/hyperactdoting/composer-plugin/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 439 This file is loaded in full into every session.
When invoked 439 The same file — it is already loaded in full.
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 $0.00439 $0.00439
Opus 5.5 $0.00176 $0.00176
Sonnet 5.5 $0.00088 $0.00088
Haiku 4.5 $0.00044 $0.00044

Measured 2mo ago against content hash 835f8762ef2c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

composer-plugin AGENTS.md 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 2mo 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.

AGENTS.md · 49 lines

What it actually says

Composer

Composer is a real-time collaborative markdown editor. This plugin gives your terminal agent a way to open a doc, listen to comments, and reply inline as a first-class collaborator.

What you have

When this plugin is loaded, the composer-mcp MCP server is registered and the following are available:

  • Skill: composer — full guidance on creating rooms, handling mentions, posting suggestions, anchoring text, and the always-on monitor loop. Invoke it with /composer or load the skill on any Composer-related work.
  • Slash command: /composer:join [url] — open a doc and spawn the monitor subagent. Use to start watching, pick up a doc someone shared, or re-attach after a previous monitor exits.
  • MCP tools under composer_* — composer_create_room, composer_join_room, composer_next_event, plus read and write tools for sections, threads, comments, and suggestions.

When to invoke the skill

Always invoke the composer skill BEFORE calling any composer_* MCP tool. The skill carries the conventions for naming, mention semantics, suggestion shape, and the subagent-spawn pattern — none of which are obvious from the tool schemas alone.

Triggers:

  • The user pastes a usecomposer.md/d/<id> URL.
  • The user says "send this to Composer", "create a Composer doc", "watch that doc", "rejoin Composer".
  • The user /composer or /composer:join directly.

What this plugin does NOT do

  • It does not run a server. The MCP connects to the hosted Composer service over WebSockets.
  • It does not store secrets. The agent's display name lives in ~/.composer/user.json on first use.

Source

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. 2mo ago First seen · 49 lines · 439 tokens per session scan A 835f8762ef2c

Subscribe to this mod's changes

composer-plugin AGENTS.md is an instructions file published in the GitHub repository hyperactdoting/composer-plugin (2 stars, last pushed 4mo ago), licensed MIT. It adds 439 tokens to every session, about $0.0018 per session on Opus 5.5. 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 2026-08-31.

Writing and docs
Related

composer-plugin AGENTS.md compared with instructions from other repositories

composer-plugin AGENTS.md next to 6 instructions from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
composer-plugin AGENTS.mdhyperactdoting/composer-pluginInstructions file24mo agoMITA439Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscodeInstructions file195ktodayMITA9,719GitHub Copilot
next.js AGENTS.mdvercel/next.jsInstructions file143ktodayMITA7,461Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscodeInstructions file195ktodayMITA5,516GitHub Copilot
langchain AGENTS.mdlangchain-ai/langchainInstructions file149ktodayMITA4,680Codex, OpenCode
vscode copilot-instructions.mdmicrosoft/vscodeInstructions file195ktodayMITA3,093GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file275k3d agoMITA4,313Codex, OpenCode