HTTP servers without an Authorization header use OAuth. Connections send the stored token and refresh it after a 401; /mcp login runs the browser authorization code flow (PKCE, dynamic client registration) with a loopback callback or a pasted redirect URL, and /mcp logout removes the credentials. Tokens are stored per server URL in mcp-auth.json. Pre-registered clients are configured with the oauth block.
Adds a built-in mcp extension that reads mcp.json (agent dir, and .pi/mcp.json for trusted projects) in the common mcpServers format, connects stdio and streamable HTTP servers at session start, and registers their tools as mcp__<server>__<tool>. Calls go through the regular tool pipeline, so hooks and permission extensions apply. /mcp shows server status.
By default a server's tools are codemode-only: the new nestedOnly tool flag keeps them executable for other tools but out of the model's tool declarations, and pi activates the codemode tool for them. "exposure": "direct" declares them to the model as well. structuredContent from tools with an outputSchema reaches codemode scripts as data.
