ToolSearchTool for authored tools, mirroring connection__search (similar to claude cowork/code)

[charlie-maloney]

Connection tools get deferred discovery via connection__search, so hundreds of remote tools cost nothing in context. Authored tools don't... every descriptor loads up front.

For first-party agents this is awkward: authored tools are the right way to expose your own backend (direct code access, no HTTP hop), but the only way to get scalable discovery is to stand up an MCP/OpenAPI server in front of your own code and consume it over a network hop with duplicate schemas.

defineDynamic helps when the tool set depends on the caller, but not when it's just large (one tool per operation/table/admin action).

My proposal...an opt-in flag that keeps a tool out of the model's tool list and makes it discoverable through a built-in tool__search in the default harness:

default defineTool({
  description: "Reindex a tenant's search cluster.",
  inputSchema: z.object({ tenantId: z.string() }),
  discovery: "deferred", // omit = today's eager behavior
  async execute(input, ctx) { ... },
});

Happy to prototype if there's interest.