agentmods.dev

codex copilot-instructions.md

A project guide for AI coding agents working on Codex, a TypeScript application with a web client, server, and Model Context Protocol (MCP) interface.

In plain words
What is it for?
Understanding the codebase, using its MCP server, running critical commands, and deploying the application with Docker.
Why use it?
It gives agents the project structure, important commands, data flow, security details, and deployment instructions so they can make informed changes.

Instructions file for GitHub Copilot

9 2d ago A scan 2,462 tokens original MIT
View the source file bocan/codex
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/bocan/codex/copilot-instructions
Clone the repo
git clone --depth 1 https://github.com/bocan/codex

Made for: GitHub Copilot.

Per session 2,462 This file is loaded in full into every session.
When invoked 2,462 The same file — it is already loaded in full.
Security scan A 0 findings. 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 $0.02462 $0.02462
Opus 5 $0.01231 $0.01231
Sonnet 5 $0.00492 $0.00492
Haiku 4.5 $0.00246 $0.00246

Measured yesterday against content hash a8de4e22b7f3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codex copilot-instructions.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 yesterday.

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.

.github/copilot-instructions.md · 220 lines

How it starts

The opening of the file, as written. The whole thing — 220 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codex - AI Coding Instructions

Architecture Overview

Codex is a full-stack TypeScript monorepo using npm workspaces with three packages:

  • Root (/) - Workspace orchestration, shared devDependencies
  • Server (/server) - Express REST API on port 3001 + MCP server on port 3002
  • Client (/client) - React SPA on port 3000 (Vite dev server proxies /api to server)

Data flow: React components → api.ts service → Express routes → FileSystemService → /data directory (markdown files).

MCP flow: AI agents → MCP server (port 3002) → MCP tools → FileSystemService → /data directory.

Production mode: Express serves both API and static React build from port 3001 only (see server/src/index.ts static file serving section).

MCP Server Architecture

The Model Context Protocol (MCP) server allows AI agents to interact with Codex programmatically:

  • Location: server/src/mcp/ - Separate from REST API
  • Port: 3002 (configurable via MCP_PORT)
  • Protocol: HTTP-based MCP with session management
  • Tools: 16 registered tools (pages, folders, attachments)
  • Resources: Access pages via codex://page/{path} URIs
  • Security: API key authentication via MCP_API_KEY environment variable

Tool registration pattern: All tools imported in server/src/mcp/tools/registry.ts and wrapped with asRegisteredTool(). Each tool uses Zod schemas for input validation and returns structured ToolResult objects.

Critical Commands

make dev          # Start both server (3001) and client (3000)
make test         # Run all tests (server: Jest, client: Vitest)
make install      # Fresh install all dependencies from root
make build        # Build both server and client for production

MCP Development:

MCP_ENABLED=true npm run dev -w server    # Start server with MCP on port 3002
npm run dev:mcp -w server                 # Dedicated MCP dev script

Important: Dependencies install at the root level only. Run npm ci or make install from root, not from subdirectories. The root package-lock.json manages all workspace dependencies.

Read the full file on GitHub · 220 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. yesterday First seen · 220 lines · 2,462 tokens per session scan A a8de4e22b7f3

Subscribe to this mod's changes

codex copilot-instructions.md is an instructions file published in the GitHub repository bocan/codex (9 stars, last pushed 2d ago), licensed MIT. It adds 2,462 tokens to every session, about $0.0123 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 2026-08-31.

Backend and APIsDevOps and cloudFrontendReActdocument-storemarkdownmcpmcp-serverwiki
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