docs: fix outdated Codex MCP setup instructions

- Replace broken config.toml + 'codex mcp login' primary path with
  'codex mcp add sourcebot --url <URL>' which matches Settings → MCP
- Add tip near Getting Started pointing users to Settings → MCP for
  easiest setup (one-click install cards)
- Update Codex docs link to current official location
- Fix API key path to use CLI flag instead of manual config.toml editing

Co-authored-by: Michael Sukkarieh <msukkari@users.noreply.github.com>

Author: cursoragent

docs/docs/features/mcp-server.mdx

@@ -27,6 +27,10 @@ You can read more about the options in the [authorization](#authorization) secti
     If [anonymous access](https://docs.sourcebot.dev/docs/configuration/auth/access-settings#anonymous-access) is enabled on your Sourcebot instance, no OAuth token or API key is required. You can connect directly to the MCP endpoint without any authorization.
 </Note>
 
+<Tip>
+    **Fastest setup:** Open **Settings → MCP** in your Sourcebot deployment to copy the Server URL and use one-click install cards for supported clients. The examples below are useful when you need to customize the URL for self-hosted deployments or use API key authentication.
+</Tip>
+
 <Note>
     The examples below add the MCP server and connect it to Sourcebot's public deployment at [app.sourcebot.dev](https://app.sourcebot.dev). Replace the URL with your own Sourcebot deployment as needed.
 </Note>
@@ -145,30 +149,29 @@ You can read more about the options in the [authorization](#authorization) secti
     </Accordion>
 
     <Accordion title="Codex">
-        [Codex MCP docs](https://developers.openai.com/codex/mcp)
-
-        Add the following to your `~/.codex/config.toml` file:
+        [Codex MCP docs](https://learn.chatgpt.com/docs/extend/mcp)
 
         <Tabs>
             <Tab title="OAuth">
                 <LicenseKeyRequired feature="OAuth" />
 
-                ```toml
-                [mcp_servers.sourcebot]
-                url = "https://app.sourcebot.dev/api/mcp"
-                ```
-
-                Replace `https://app.sourcebot.dev` with wherever your Sourcebot instance is hosted. Then run the following to authenticate:
+                Run the following command:
 
                 ```sh
-                codex mcp login sourcebot
+                codex mcp add sourcebot --url https://app.sourcebot.dev/api/mcp
                 ```
+
+                Replace `https://app.sourcebot.dev` with wherever your Sourcebot instance is hosted. Codex will automatically detect OAuth support and prompt you to authorize in your browser when you first connect.
+
+                <Tip>
+                    Open **Settings → MCP** in your Sourcebot deployment and click **Copy command** on the Codex card for a ready-to-run command with the correct Server URL.
+                </Tip>
             </Tab>
             <Tab title="API Key">
-                ```toml
-                [mcp_servers.sourcebot]
-                url = "https://app.sourcebot.dev/api/mcp"
-                bearer_token_env_var = "SOURCEBOT_API_KEY"
+                Run the following command:
+
+                ```sh
+                codex mcp add sourcebot --url https://app.sourcebot.dev/api/mcp --bearer-token-env-var SOURCEBOT_API_KEY
                 ```
 
                 Replace `https://app.sourcebot.dev` with wherever your Sourcebot instance is hosted, then set your API key as an environment variable: