Toolsets

A toolset is a bundle of tools that BitRouter advertises to the model and executes itself during the server-tool loop. It's the seam that makes router-run tools provider-agnostic: each toolset decides which tools to advertise on a given request and how to run them, and BitRouter composes several into the single set the model sees.

What a toolset does

Every toolset answers two questions for a request: which tools to advertise, and how to run a call to one of them. BitRouter keeps a registry of toolsets; when the model calls a tool, the registry routes the call to the toolset that owns that name. Because several toolsets can be active at once, tool names are prefixed to avoid collisions — the search tool from the demo server is advertised as demo__search.

Kinds of toolset

• MCP-backed — one per upstream MCP server; its tools are the server's tools, run through the gateway.
• Model-backed — Advisor, SubAgent, and Fusion, each wrapping a nested model call.
• In-process — tools implemented directly in the router.

Conditional availability

A toolset doesn't have to advertise on every request. It can check what the caller declared and stay silent otherwise — which is how the model-backed tools work: Advisor only appears when the request declares bitrouter:advisor, and likewise for SubAgent and Fusion. The model only ever sees the tools that request actually opted into.