tools/pi-ai: typed parameter schemas so pi-durable can type tool args #194

createPiTools declares every tool's parameters as PiJSONSchema:

interface PiJSONSchema {
  type: "object";
  properties?: Record<string, unknown>;
  required?: string[];
  [key: string]: unknown;
}

pi-durable 1.0 types a tool's execute(args) as Static<TParameters>, inferred from parameters. With PiJSONSchema that comes out as {}, so every Workspace tool registered on pi gets untyped arguments. The schema is fine at runtime (pi validates plain JSON Schema with TypeBox); only the static type is lost.

Seen in the agents pi harness example, examples/next/harnesses/pi/src/workspace.ts on cloudflare/agents#2451:

draft.set(tool.name, {
  parameters: tool.parameters,   // PiJSONSchema
  async execute(args) { … }      // args: {}
});

Options:

• Declare each tool's schema as its exact literal type (satisfies, not widened to PiJSONSchema), and type tools as a tuple or a record keyed by name so each tool keeps its own schema type.
• Build the pi-ai schemas with TypeBox (Type from @earendil-works/pi-ai, or typebox as an optional peer). Static then infers the args.
• Also export a per-tool execute(args, context) for each declaration, so a pi-durable host doesn't have to route by name through the single execute(call).