What is agentapi AGENTS.md?

An instruction file for agentapi, a Go server that exposes coding agents through an HTTP API and a web chat page. It documents build, test, generation, and run commands for agents such as Claude, Aider, Goose, Codex, and Gemini.

Use it when developing agentapi, running its Go tests, building the binary or embedded chat interface, generating its API schema, or connecting it to a coding agent.

It gives the coding agent the exact commands and project conventions needed to build, test, generate files, and start the server. It also explains where the chat page and API documentation are available.

How coder/agentapi configures Codex and OpenCode

About the project

AgentAPI is an HTTP server that lets software send messages to and read conversations from command-line coding agents. Developers use it to build unified chat interfaces, connect agents through MCP, or have one coding agent control another.

coder/agentapi · 1,496 stars · on GitHub

Reuse

Borrowing it

Nothing to install: this file belongs to coder/agentapi. 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/coder/agentapi/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/coder/agentapi

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/coder/agentapi/agents-md/github.svg)](https://agentmods.dev/instructions/coder/agentapi/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/coder/agentapi/agents-md"><img src="https://agentmods.dev/badge/instructions/coder/agentapi/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/coder/agentapi/agents-md"><img src="https://agentmods.dev/badge/instructions/coder/agentapi/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 812 This file is loaded in full into every session.

When invoked 812 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.

Model	Per session	Once invoked
Fable 5.1	$0.00812	$0.00812
Opus 5.5	$0.00325	$0.00325
Sonnet 5.5	$0.00162	$0.00162
Haiku 4.5	$0.00081	$0.00081

Measured 2mo ago against content hash fcee578e30bf, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

agentapi 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 · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

This file provides guidance to AI agents working with code in this repository.

Build Commands

make build - Build the binary to out/agentapi (includes chat UI build)
make embed - Build the chat UI and embed it into Go
go build -o out/agentapi main.go - Direct Go build without chat UI
go generate ./... - Generate OpenAPI schema and version info

Testing

go test ./... - Run all Go tests
Tests are located alongside source files (e.g., lib/httpapi/server_test.go)

Development Commands

agentapi server -- claude - Start server with Claude Code agent
agentapi server -- aider --model sonnet - Start server with Aider agent
agentapi server -- goose - Start server with Goose agent
agentapi server --type=codex -- codex - Start server with Codex (requires explicit type)
agentapi server --type=gemini -- gemini - Start server with Gemini (requires explicit type)
agentapi attach --url localhost:3284 - Attach to running agent terminal
Server runs on port 3284 by default
Chat UI available at http://localhost:3284/chat
API documentation at http://localhost:3284/docs

Architecture

This is a Go HTTP API server that controls coding agents (Claude Code, Aider, Goose, etc.) through terminal emulation.

Core Components:

main.go - Entry point using cobra CLI framework
cmd/ - CLI command definitions (server, attach)
lib/httpapi/ - HTTP server, routes, and OpenAPI schema
lib/screentracker/ - Terminal output parsing and message splitting
lib/termexec/ - Terminal process execution and management
lib/msgfmt/ - Message formatting for different agent types (claude, goose, aider, codex, gemini, amp, cursor-agent, cursor, auggie, custom)
chat/ - Next.js web UI (embedded into Go binary)

Key Architecture:

Runs agents in an in-memory terminal emulator
Translates API calls to terminal keystrokes
Parses terminal output into structured messages
Supports multiple agent types with different message formats
Embeds Next.js chat UI as static assets in Go binary

Read the full file on GitHub · 86 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.

2mo ago First seen · 86 lines · 812 tokens per session scan A fcee578e30bf

Subscribe to this mod's changes

agentapi AGENTS.md is an instructions file published in the GitHub repository coder/agentapi (1,496 stars, last pushed 1mo ago), licensed MIT. It adds 812 tokens to every session, about $0.0032 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.

agentapi AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
agentapi AGENTS.mdcoder/agentapi	Instructions file	1.5k	1mo ago	MIT	A	812	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

agentapi: Instructions file for Codex