MCP connection

This page explains how to connect an MCP client to Aether and what to expect once connected.

Endpoint

After nexus.start(), Nexus exposes MCP over HTTP at:

• http://<host>:8000/nexus/mcp

If Nexus runs locally, the endpoint is typically:

• http://localhost:8000/nexus/mcp

Before you connect

• Start Nexus successfully (license token is required).
• Confirm GET /health returns {"status":"ok"}.
• Ensure your client can reach the same host/port where Nexus is running.

What you get through MCP

MCP tools are registered from your declared runtime objects:

• Sigils: read tools for all Sigils, plus write tools for writable Sigils.
• Weaves: read-only status tool for each Weave.

Tool names are generated from Sigil/Weave metadata and sanitized for MCP-safe naming.

Connection flow

1. Start your Aether app (nexus.start()).
2. In your MCP client, add a server using the URL http://<host>:8000/nexus/mcp.
3. Refresh or list tools.
4. Call a Sigil read tool first to verify connectivity.

Troubleshooting

• Cannot connect: verify host/port reachability and firewall rules.
• No tools listed: ensure Sigils/Weaves are declared before nexus.start().
• Write tool missing: check whether the Sigil is configured with writable=False.

Related

• Nexus, Sigils, and Weaves overview
• Nexus reference
• Sigil reference
• Weave reference