chorus mcp-server.instructions.md

chorus mcp-server.instructions.md is an instructions file for GitHub Copilot from valpere/chorus. It costs 251 tokens per session, scanned A, original, MIT.

Review instructions for an OpenCode MCP server in Chorus, a collection that coordinates several AI coding command-line tools.

In plain words
What is it for?
Checking tool handlers, empty arguments, parallel execution, error handling, output formatting, delegate limits, and imports.
Why use it?
They catch implementation mistakes that could make server tools fail silently or cause parallel agent work to behave incorrectly.

Instructions file for GitHub Copilot

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 instructions/valpere/chorus/mcp-server
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.

agentmods badge for chorus mcp-server.instructions.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/valpere/chorus/mcp-server.svg)](https://agentmods.dev/instructions/valpere/chorus/mcp-server)
Your own site
<a href="https://agentmods.dev/instructions/valpere/chorus/mcp-server"><img src="https://agentmods.dev/badge/instructions/valpere/chorus/mcp-server.svg" alt="Measured on agentmods" height="20"></a>
Per session 251 This file is loaded in full into every session.
When invoked 251 The same file — it is already loaded in full.
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 $0.00251 $0.00251
Opus 5 $0.00125 $0.00125
Sonnet 5 $0.00050 $0.00050
Haiku 4.5 $0.00025 $0.00025

Measured 3d ago against content hash 5c1ea6049fe2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

chorus mcp-server.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 3d 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.

- No unused imports. The file uses only `spawn`, `spawnSync` from `child_process` and `Server`/`StdioServerTransport` from the MCP SDK.
.github/instructions/mcp-server.instructions.md · 14 lines

What it actually says

OpenCode MCP server review guidelines

  • Every new tool in TOOLS must have a matching case in the tools/call switch. Missing cases cause silent failures.
  • Tools with no required args (e.g. parallel_review) must not throw on args = {}. The handler checks args = {} as default.
  • Parallel orchestration helpers (runCouncil, runParallelReview, etc.) must use Promise.all — never sequential awaits.
  • Individual agent failures inside runParallel must be caught and returned as [error: message] text, not thrown. One failing agent must not reject the whole Promise.all.
  • delimit() output format must use (U+2550) separator lines and AGENT: NAME headers to match the companion.mjs format.
  • Do not add OpenCode as a delegate in any parallel orchestration function — its stdout is not capturable (TUI limitation).
  • No unused imports. The file uses only spawn, spawnSync from child_process and Server/StdioServerTransport from the MCP SDK.
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. 3d ago First seen · 14 lines · 251 tokens per session scan A 5c1ea6049fe2

Subscribe to this mod's changes

chorus mcp-server.instructions.md is an instructions file published in the GitHub repository valpere/chorus (10 stars, last pushed 3mo ago), licensed MIT. It adds 251 tokens to every session, about $0.0013 per session on Opus 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.