# Codex MCP: how to connect MCP servers to OpenAI's Codex CLI

OpenAI's Codex CLI configures MCP in TOML — `[mcp_servers]` tables in `~/.codex/config.toml` — or with one `codex mcp add` command that writes the same file. Remote servers take a URL; local servers take a launch command. Every brand page on mcpyet.com tells you which kind you're dealing with — 212 of 234 brands have official servers ([full index](https://mcpyet.com/browse.md)).

## Local (stdio) servers

The quick way is the command:

```sh
codex mcp add example -- npx -y @vendor/mcp-server

# see what's configured
codex mcp list
```

Or write the TOML yourself. Note the syntax differences from every other client's JSON: tables instead of nested objects, and `env` as its own table:

```toml
[mcp_servers.example]
command = "npx"
args = ["-y", "@vendor/mcp-server"]

[mcp_servers.example.env]
VENDOR_API_KEY = "sk-…"
```

Python servers use `uvx` as the command. To pass through variables already set in your shell instead of writing values into the file, list them in `env_vars = ["VENDOR_API_KEY"]`.

## Remote (hosted) servers

Swap `command` for `url`. Authentication defaults to OAuth — Codex sends you through the vendor's sign-in when you run `codex mcp login`:

```toml
[mcp_servers.figma]
url = "https://mcp.figma.com/mcp"
```

```sh
codex mcp login figma
```

For servers that take a token instead of OAuth, point at an environment variable rather than pasting the secret into the file:

```toml
[mcp_servers.example]
url = "https://mcp.example.com/mcp"
bearer_token_env_var = "EXAMPLE_TOKEN"
```

Servers you can add this way right now: [fal.ai](https://mcpyet.com/mcp/fal-ai.md), [Atlassian](https://mcpyet.com/mcp/atlassian.md), [Datadog](https://mcpyet.com/mcp/datadog.md), [Buffer](https://mcpyet.com/mcp/buffer.md), [Google Drive](https://mcpyet.com/mcp/google-drive.md), [Confluence](https://mcpyet.com/mcp/confluence.md).

## Useful per-server options

| Option | Does |
| --- | --- |
| `enabled = false` | Turns a server off without deleting its config |
| `enabled_tools` / `disabled_tools` | Filters which of the server's tools Codex sees |
| `default_tools_approval_mode` | `auto`, `prompt`, `writes` or `approve` — when Codex asks before a call |
| `startup_timeout_sec` / `tool_timeout_sec` | Raises timeouts for slow-starting servers or long-running tools |
| `http_headers` | Extra headers for remote servers |

## When it doesn't work

| Symptom | Usual cause | Fix |
| --- | --- | --- |
| Server never appears | Invalid TOML | Table headers are `[mcp_servers.name]` — dots, not slashes; strings quoted |
| Appears, fails to start | `npx` not on PATH | Use the absolute path from `which npx` |
| Starts, then exits | Missing API key | Add it under `[mcp_servers.name.env]` or list it in `env_vars` |
| Remote server 401s | No auth established | Run `codex mcp login <name>`, or set `bearer_token_env_var` |
| Server slow, gets killed | Default startup timeout | Raise `startup_timeout_sec` for that server |

To see why a local server is failing, run its command directly in a terminal — the error it prints there is the one Codex is swallowing.

## A word on trust

An MCP server runs with the credentials you give it, and Codex will act on whatever the server returns. Prefer official servers where they exist (<https://mcpyet.com/browse/official/>), give community ones scoped, revocable keys, and keep the approval mode away from `auto` for anything that writes. More in the [MCP security guide](https://mcpyet.com/guides/mcp-security.md).

## Questions

**Where is the Codex MCP config file?**
~/.codex/config.toml — servers live in [mcp_servers.<name>] tables. codex mcp add writes to the same file, so you can mix the command and hand-editing freely.

**Does Codex support remote MCP servers?**
Yes. Give the server a url instead of a command, and Codex connects over streamable HTTP. Auth defaults to OAuth — run codex mcp login <name> to sign in — or set bearer_token_env_var to send a token from your environment instead.

**How do I temporarily disable a server without deleting it?**
Set enabled = false in its [mcp_servers.<name>] table. The config stays intact and one line flips it back on.

**Can I limit which tools a server exposes to Codex?**
Yes — enabled_tools and disabled_tools arrays on each server filter its tool list, and default_tools_approval_mode controls when Codex asks before calling one (auto, prompt, writes, or approve).

**Does the Codex IDE extension use the same servers?**
It reads the same configuration. In the extension, open the gear menu → MCP servers to manage them from the UI; changes need an extension restart to take effect.

Related guides: [Claude](https://mcpyet.com/connect/claude.md) · [Cursor](https://mcpyet.com/connect/cursor.md) · [Gemini CLI](https://mcpyet.com/connect/gemini-cli.md)

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Source: https://mcpyet.com/connect/codex/ — data refreshed 2026-08-11