Codex¶
Prerequisite: complete the Unity package installation.
Install and Sign In¶
Install Codex and complete its first-run sign-in using the official Codex CLI guide:
External MCP Client¶
Unity Biome MCP creates .codex/config.toml in the Unity project. Codex loads project-scoped MCP configuration only for a trusted project, so review the generated command before trusting the checkout. Restart Codex after Unity creates or updates the file, open Codex from that project, and run:
Confirm that unity-biome-mcp is listed, then run the first connection check. Inside an interactive Codex session, /mcp shows the same connection and tool status.
Codex uses TOML. Do not paste the standard mcpServers JSON into config.toml.
For user-level configuration instead, use the global configuration command with client key codex. It writes ~/.codex/config.toml.
Codex's ChatGPT desktop app, CLI, and IDE extension share the Codex-host MCP configuration. See the official Codex MCP guide for current client behavior; use this guide for the Unity-generated entry.
For optional project-local skills and generated Codex agents, follow Install AI Skills and Agents. The guide explains ownership checks and the Claude-to-Codex sync.
In-Unity Chat¶
- Open MCP > Settings > Chat Settings > Codex Settings.
- Confirm that the Codex binary is detected.
- Open MCP > Chat and select Codex.
MCP Chat uses the Codex CLI's existing authentication and starts codex exec for each turn. See Chat Backends for current session behavior.
Client-specific Troubleshooting¶
| Symptom | Action |
|---|---|
| Codex is not found | Make codex available on the login-shell PATH, then restart Unity |
| External Codex reports an unknown server | Confirm the project is trusted, .codex/config.toml exists, and codex mcp list includes unity-biome-mcp |
| A Chat turn times out too early | Codex uses a higher inactivity floor; review Chat Settings before increasing it further |