ext-apps: Instructions file for Codex

AGENTS.md

ext-apps AGENTS.md is an instructions file for Codex, OpenCode from modelcontextprotocol/ext-apps. It costs 1,216 tokens per session, scanned A, original, no licence file.

Project instructions for the official MCP Apps SDK repository, which provides the specification and code for interfaces embedded in AI assistants and served by MCP servers.

In plain words
What is it for?
Use them when installing dependencies, building the SDK and examples, or working on the ext-apps project.
Why use it?
They give coding agents the project’s expected commands, dependency setup, and build process, reducing mistakes when changing the repository.

Instructions file for CodexOpenCode ✓ vendor

Written for Codex and OpenCode: the file is AGENTS.md.

This is modelcontextprotocol/ext-apps's own configuration. It tells Codex and OpenCode how to work on ext-apps 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 ext-apps configures →

Reuse

Borrowing it

Nothing to install: this file belongs to modelcontextprotocol/ext-apps. 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/modelcontextprotocol/ext-apps/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/modelcontextprotocol/ext-apps

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 ext-apps AGENTS.md

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

Your own site · 80×15
<a href="https://agentmods.dev/instructions/modelcontextprotocol/ext-apps/agents-md"><img src="https://agentmods.dev/badge/instructions/modelcontextprotocol/ext-apps/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 1,216 This file is loaded in full into every session.
When invoked 1,216 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 unknown 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 $0.01216 $0.01216
Opus 5.5 $0.00486 $0.00486
Sonnet 5.5 $0.00243 $0.00243
Haiku 4.5 $0.00122 $0.00122

Measured 1mo ago against content hash 661fd9e6469d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ext-apps 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 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.

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 · 104 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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 Changed · +32 tokens per session 661fd9e6469d
  2. 2mo ago First seen · 104 lines · 1,184 tokens per session scan A 77e272fa0e8a

Subscribe to this mod's changes

ext-apps AGENTS.md is an instructions file published in the GitHub repository modelcontextprotocol/ext-apps (3,056 stars, last pushed 2d ago), with no licence file. It adds 1,216 tokens to every session, about $0.0049 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 2026-08-30.

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