Cmd. /mcp
List configured MCP tools and inspect server diagnostics.
Written and reviewed by Eric Han · Co-founder & CTO, reopt
Key takeaways
- List configured MCP tools and inspect server diagnostics.
- If tools are missing, narrow the cause with
/mcp verbose; from 0.161.0 you can sign in to an MCP server from a running session with/mcp login <name>.
Purpose
List configured MCP tools and inspect server diagnostics; the 0.161.0 release notes add /mcp login to sign in to a server from the session.
/mcpAvailability
| Field | Value |
|---|---|
| Input surface | Running CLI prompt |
| Kind | Built-in |
| Status | Current reference |
| Aliases | — |
| Documented minimum | Not specified |
| Reviewed against | 2026-10-23 · Codex CLI 0.163.0 |
The installed command menu and account or organization settings determine availability.
Examples
/mcp
/mcp login githubWhen to use it
- Run
/mcpbefore asking Codex to use an external tool. - Run
/mcp verbosewhen a server is present but a tool is missing or failing. - Confirm the design-context, metadata, and screenshot tools before starting from a Figma node.
Choosing related commands
| Command | Difference | Choose It When |
|---|---|---|
/mcp | Lists MCP tools and diagnostics | You need the actual tool surface |
/apps | Inserts app mentions | You need a connector in the prompt |
/plugins | Manages packaged capabilities | You need to inspect installed bundles |
Effects and persistence
Inspects configured MCP servers and exposed tools. /mcp login followed by a server name starts that server's sign-in from the active terminal session (per the 0.161.0 release notes; not yet in the official table). Use the appropriate codex mcp subcommand to add or remove servers.
/mcp lists configured Model Context Protocol tools available to Codex. Use /mcp verbose for
server-level diagnostics.
Authentication in 0.155.0
Local TUI sessions on supported Macs can use Touch ID verification for MCP requests. Expired OAuth credentials are reported more accurately, with reconnect guidance after refresh failure.
OAuth client secrets in 0.158.0
Servers that require a pre-registered OAuth client secret connect through codex mcp add --oauth-client-secret or oauth.client_secret in the server configuration. The secret must be set together with a client ID and is kept out of debug output and authorization URLs. The same release adds mcp_servers.<name>.tool_input_schema_max_bytes (5,000 bytes by default) to adjust when a large MCP tool's input schema is compacted.
In-session sign-in in 0.161.0
From 0.161.0, /mcp login <name> signs in to an MCP server from an active session. According to the pull-request description, it opens the authorization URL in the browser and shows success or failure in the thread that ran the command. The shell command codex mcp login <name> still works. The official slash table does not list the login argument yet, so confirm the behavior in the installed build.
/mcp login <name>Cautions
- Tool availability can differ by profile, workspace, and trust state.
- Pair MCP write or destructive tools with
/permissionsand team policy. - Do not read “deprecated” as “already removed,” and do not postpone migration merely because the old subcommand still starts.
Official sources
Complete command list · Verification scope · History for this command