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. Restart Codex after Unity creates or updates this file, open Codex from that project, and run the first connection check.
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.
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 .codex/config.toml exists in the Unity project and restart Codex |
| A Chat turn times out too early | Codex uses a higher inactivity floor; review Chat Settings before increasing it further |