[AI agent] tool call status update

export const kaolinAgent = new Agent(components.agent, {
  chat: xai("grok-3"),
  name: "Kaolin agent",
  ...
  tools: {
    searchContacts: createTool({
      description: "Search for a contact by name, email, or phone number",
      args: z.object({
        searchQuery: z.string(),
      }),
      handler: async (ctx, args) => {
        const program: Effect.Effect<
          TSearchContactsHandlerReturn,
          never,
          never
        > = Effect.gen(function* () {
          const contacts = yield* Effect.promise(() =>
            ctx.runQuery(internal.ai.tools.searchContacts, {
              userId: ctx.userId!,
              searchQuery: args.searchQuery,
            })
          );

          yield* Effect.promise(() =>
            ctx.agent.completeMessage(ctx, {
              threadId: ctx.threadId!,
              messageId: ctx.messageId!,
              result: { kind: "success" },
            })
          );

          return yield* Effect.succeed(contacts);
        });

        return program.pipe(
          Effect.catchAllCause((cause) => {
            return Effect.gen(function* () {
              yield* Effect.promise(() =>
                ctx.agent.completeMessage(ctx, {
                  threadId: ctx.threadId!,
                  messageId: ctx.messageId!,
                  result: { kind: "error", error: cause._tag },
                })
              );
            });
          }),
          Effect.runPromise
        );
      },
    }),
  },
});