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chorus: Instructions file for GitHub Copilot

.github/copilot-instructions.md

chorus copilot-instructions.md is an instructions file for GitHub Copilot from valpere/chorus. It costs 546 tokens per session, scanned A, original, MIT.

A set of coding instructions for Chorus, a collection of plugins that lets AI coding command-line tools delegate work to one another. It documents how Chorus is organised across Claude Code, OpenCode, Gemini CLI, and Codex.

In plain words
What is it for?
Use it when developing, reviewing, or testing Chorus plugins, scripts, MCP tools, or skill files.
Why use it?
It gives contributors the project’s expected file structure, code style, command metadata, and known implementation rules when changing or reviewing Chorus.

Instructions file for GitHub Copilot

Written for GitHub Copilot: a Copilot instructions file. Also seen: mentions Claude Code; mentions Codex; mentions Gemini CLI.

This is valpere/chorus's own configuration. It tells GitHub Copilot how to work on chorus 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 chorus configures →

not rated 10repo 5mo ago A scan 546 tokens original MIT
View source ↗ valpere/chorus valpere.github.io
Reuse

Borrowing it

Nothing to install: this file belongs to valpere/chorus. 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/valpere/chorus/main/.github/copilot-instructions.md
Clone the repo
git clone --depth 1 https://github.com/valpere/chorus

Made for: GitHub Copilot.

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.

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README.md
[![agentmods](https://agentmods.dev/badge/instructions/valpere/chorus/copilot-instructions/github.svg)](https://agentmods.dev/instructions/valpere/chorus/copilot-instructions)
Your own site
<a href="https://agentmods.dev/instructions/valpere/chorus/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/valpere/chorus/copilot-instructions/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 chorus copilot-instructions.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/valpere/chorus/copilot-instructions"><img src="https://agentmods.dev/badge/instructions/valpere/chorus/copilot-instructions.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 546 This file is loaded in full into every session.
When invoked 546 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 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 $0.00546 $0.00546
Opus 5.5 $0.00218 $0.00218
Sonnet 5.5 $0.00109 $0.00109
Haiku 4.5 $0.00055 $0.00055

Measured 1mo ago against content hash 0b679380e1d5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

chorus copilot-instructions.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 1mo 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.

- `plugins/*/scripts/companion.mjs` — Node.js ESM scripts that spawn external CLI processes. Use `spawn` with `stdio: 'pipe'` when output must be captured; use `stdio: 'inherit'` for pass-through. Use `spawnSync` only fo
.github/copilot-instructions.md · 29 lines

How it starts

The opening of the file, as written. The whole thing — 29 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Chorus — Copilot Instructions

Chorus is a cross-agent plugin collection that lets AI coding CLIs delegate tasks to each other. It exposes capabilities on four installation surfaces: Claude Code (slash-command plugins), OpenCode (MCP npm package), Gemini CLI (SKILL.md skills), and Codex (SKILL.md skills).

Architecture

  • plugins/*/commands/*.md — Claude Code slash command definitions. Frontmatter must include description, argument-hint, disable-model-invocation: true, and allowed-tools.
  • plugins/*/scripts/companion.mjs — Node.js ESM scripts that spawn external CLI processes. Use spawn with stdio: 'pipe' when output must be captured; use stdio: 'inherit' for pass-through. Use spawnSync only for version checks.
  • for-opencode/src/index.js — MCP stdio server using @modelcontextprotocol/sdk. Tools are defined in a TOOLS array; the tools/call handler switches on request.params.name.
  • for-gemini/*/SKILL.md and for-codex/*/SKILL.md — natural-language skill files. Gemini frontmatter requires name, description, license, metadata. Codex frontmatter requires only name and description.

Code style

  • ESM throughout (import/export). No CommonJS require.
  • No TypeScript — plain .mjs and .js files.
  • No build step. Files run directly with Node.js >= 18.18.0.
  • Prefer Promise.all for parallel agent spawns. Never await sequentially when tasks are independent.
  • Error handling: companion scripts resolve (not reject) on agent failure, returning { code, output, error } so one failed agent doesn't abort the others.

Known limitations to consider in review

  • OpenCode (opencode run) is a TUI — its stdout is not capturable. Do not add OpenCode as a parallel delegate in orchestration workflows.
  • Codex runs in a bubblewrap sandbox limited to its working directory. Parallel review and debug skills note this restriction; new Codex-facing skills must repeat the warning.
  • claude --print is the correct non-interactive invocation for Claude Code. Do not suggest claude run or bare claude.

Read the full file on GitHub · 29 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. 1mo ago First seen · 29 lines · 546 tokens per session scan A 0b679380e1d5

Subscribe to this mod's changes

chorus copilot-instructions.md is an instructions file published in the GitHub repository valpere/chorus (10 stars, last pushed 5mo ago), licensed MIT. It adds 546 tokens to every session, about $0.0022 per session on Opus 5.5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Building agentsClaude Codeai-toolscodexdeveloper-toolsgemini-cli
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