MCP Servers

MCP servers provide tools and resources that Polytoken can use during a session. Add servers in the MCP pane of polytoken config ui.

Add a server

Choose a server name, then select its transport. For a local server, enter the executable in the command field and add each command-line argument as a separate item. For a remote server, enter its HTTP URL. The pane shows settings that apply to the selected transport.

Restart a local server after failure

A local stdio MCP server stops after its process exits unless you configure restart_policy. The default none policy leaves the server stopped. Set restart_policy to bounded and choose max_attempts to let Polytoken start a fresh process after a failure, with progressively longer delays between attempts. The accepted attempt range appears in the Application Configuration reference.

When Polytoken exhausts the configured attempts, the server enters Disabled and stays stopped until you enable it again. A configuration reload cancels retries for the replaced server and applies the new configuration. Manually disabling a server also cancels pending retries.

restart_policy applies only to stdio servers. HTTP servers keep their existing reconnect behavior.

Image results

MCP tool results that contain images reach vision-capable models as inline images alongside any text in the result. When the model cannot view images, Polytoken saves each image under the session directory with a name such as mcp-image-1.png. The tool result names the saved path and says that the model cannot see the image. For a result with multiple images, Polytoken sends the first image inline when the model supports vision and saves the remaining images under the session directory.

Set an API key

For an HTTP server that uses a bearer token, choose Authorization header authentication and enter the header value. Prefer an environment reference such as ${MCP_AUTHORIZATION} over a literal secret. Polytoken redacts literal authorization values and stdio server environment values in the configurator display and save preview.

Hide MCP tools

Set mcp_servers.<name>.block_list to hide MCP tools from the model. Each entry matches a synthesized tool name such as mcp__github__admin_delete. The * character matches any sequence of characters, so mcp__github__admin_* hides every admin_ tool from the github server. Entries without * match one tool name exactly. Polytoken rejects entries containing [, {, or ?; use * for wildcard matching.

Sign in with OAuth

Choose the OAuth login action in the MCP pane to sign in without starting a daemon. You can also run polytoken auth mcp login --server <server> from a terminal.

OAuth uses a loopback callback by default. If the server has a fixed redirect URI, Polytoken uses that URI and asks you to paste the completed callback URL instead of opening a local callback listener. The URL you paste must match the server’s configured redirect URI: the scheme, host, effective port, and path have to be the same, and the URL must not carry a user-info component such as user@host. Polytoken ignores query and fragment differences and treats an explicit default port as equivalent to omitting the port. Any other URL fails before Polytoken exchanges the authorization code for tokens.

See Application Configuration for the complete MCP server key list and configuration details.