Codex settings without JSON: models, reasoning, MCP

Stop hand-editing JSON. CodexUse ships a Config panel with quick selects for models, approval policy, sandbox mode, and MCP servers. It writes to the same Codex CLI files already on disk.

What you can change from the UI

• Model and review model: Pick from defaults or type a custom name.
• Reasoning effort and summary style: Set effort and summary keywords without guessing JSON keys.
• Verbosity: Control how chat replies are logged.
• Approval policy: Never, on-request, on-failure, or untrusted prompts.
• Sandbox mode: Read-only, workspace-write, or danger-full-access.
• MCP servers: Add HTTP or STDIO servers, set commands or URLs, timeouts, tool allow and deny lists, headers, env vars, and whether the RMCP client is enabled.
• Manual edit: Paste JSON directly if you want full control.

Set defaults in minutes

1. Open CodexUse.
2. Click the Settings gear, then choose config.toml.
3. Use Quick settings to set model, reasoning effort, summary style, verbosity, approval, and sandbox mode.
4. Click Save changes. The app writes to the Codex CLI config and keeps the same file the CLI uses.
5. Need a preset? The Apply YOLO preset button fills in a fast, opinionated set so you can test quickly.

Manage MCP servers without mistakes

• Add a server with a name, choose HTTP or STDIO, and fill command plus args or URL.
• Optional fields: working directory, env vars, HTTP headers, bearer token env var, startup and tool timeouts, tool allow and deny lists.
• Toggle Enable RMCP client if you want remote MCP. Leave it off to keep things local.
• Edits stay on your machine. Nothing syncs out.

When to use Manual edit

• You already have a config you trust and just want to paste it in.
• You need a key the quick form does not expose yet.
• You are copying a known-good JSON block between machines. CodexUse will save it as-is.

Troubleshooting saves

• If a field is invalid, the app shows a Sonner toast with the exact error. Fix the field and retry.
• Custom values are allowed; just type them in the custom inputs when the select shows “Custom value”.
• If the file is locked by another process, close that process and click save again. The app logs the failure but keeps your inputs.