OpenAI Codex

Install coree as a Codex plugin.

coree supports OpenAI Codex via the Codex plugin system.

Install

codex plugin marketplace add github:coree-ai/codex
codex plugin install coree

The first command registers the marketplace source. The second installs the plugin into Codex's plugin cache, which registers the coree MCP server.

Sandbox configuration

Codex sandboxes MCP server processes. coree needs network access (for first-run model download and remote sync) and filesystem write access (for its database and model cache). Add this to ~/.codex/config.toml, substituting your username:

[sandbox_workspace_write]
network_access = true
writable_roots = [
  "/home/you/.cache/coree",
  "/home/you/.local/share/coree"
]

Use absolute paths - ~ expansion is not reliable in TOML.

Context file

The plugin does not automatically place a context file. Copy AGENTS.md to your project root so the agent loads coree usage instructions:

curl -fsSL https://raw.githubusercontent.com/coree-ai/codex/main/AGENTS.md -o AGENTS.md

AGENTS.md is Codex's equivalent of CLAUDE.md. It covers the primary search() entry point, memory hygiene guidelines, and tool descriptions.

Hooks

Codex does not yet support installing hooks from plugins. To enable automatic context injection, add the following to ~/.codex/config.toml:

[hooks.SessionStart]
command = "npx --yes @coree-ai/coree@0.15.0 inject --type session"

[hooks.UserPromptSubmit]
command = "npx --yes @coree-ai/coree@0.15.0 inject --type prompt"

Hook	Purpose
`SessionStart`	Injects stale notes and session context at the start of each session
`UserPromptSubmit`	Injects relevant memories before each user prompt (up to 8 000 tokens)

Without these hooks, coree still works as an MCP server - you can call tools manually. The hooks add automatic context injection equivalent to the Claude Code and Gemini CLI integrations.

What gets installed

The plugin installs to ~/.codex/plugins/cache/coree/coree/<version>/:

.mcp.json - registers the MCP server: npx --yes @coree-ai/coree@<version> serve

The binary is fetched via npx on first use and cached in ~/.npm/_npx/.

Environment variables

If you use coree's remote sync, the following env vars must be set in your shell so Codex forwards them to the MCP process:

COREE__MEMORY__REMOTE_AUTH_TOKEN
COREE__MEMORY__REMOTE_URL

The plugin's .mcp.json already lists these in env_vars so Codex will forward them if they are present in your shell environment.

Verify

After installation, start a session and run:

call the diagnose mcp tool

If the filesystem sandbox is blocking writes, diagnose will report a Read-only file system error and show the remediation step.

Notes

Codex's plugin sandbox is stricter than Claude Code's. If you see the MCP server start in degraded state, check:

The sandbox_workspace_write config entry points to the correct path
The npx cache is populated (run npx --yes @coree-ai/coree@0.15.0 --version outside the sandbox once to prime it)