Tool Registry

The tool registry manages all tools available to the agent during a conversation. It tracks where each tool comes from and supports filtering by source.

Tool Sources

Every registered tool has a ToolSource that identifies its origin:

• Builtin — tools shipped with the binary (exec, web_fetch, etc.)
• Mcp { server } — tools provided by an MCP server, tagged with the server name

This replaces the previous convention of identifying MCP tools by their mcp__ name prefix, providing type-safe filtering instead of string matching.

Registration

#![allow(unused)]
fn main() {
// Built-in tool
registry.register(Box::new(MyTool::new()));

// MCP tool — tagged with server name
registry.register_mcp(Box::new(adapter), "github".to_string());
}

Filtering

When MCP tools are disabled for a session, the registry can produce a filtered copy:

#![allow(unused)]
fn main() {
// Type-safe: filters by ToolSource::Mcp variant
let no_mcp = registry.clone_without_mcp();

// Remove all MCP tools in-place (used during sync)
let removed_count = registry.unregister_mcp();
}

Schema Output

list_schemas() includes source metadata in every tool schema:

{
  "name": "exec",
  "description": "Execute a command",
  "parameters": { ... },
  "source": "builtin"
}

{
  "name": "mcp__github__search",
  "description": "Search GitHub",
  "parameters": { ... },
  "source": "mcp",
  "mcpServer": "github"
}

The source and mcpServer fields are available to the UI for rendering tools grouped by origin.