MCP Feedback & Elicitation

import { feedbackTools, FEEDBACK_INSTRUCTIONS } from '@absolutejs/mcp';

mcpServer<Caller>({
  instructions: `${myInstructions} ${FEEDBACK_INSTRUCTIONS}`,
  tools: ({ caller }) => ({
    ...myTools(caller),
    ...feedbackTools({
      caller,
      store: {
        // Each handler returns the sentence the model relays back to
        // the user — a ticket id, an SLA, a thank-you. Return nothing
        // and a sensible default is used.
        reportProblem: ({ caller, report }) => file(caller, report),
        submitFeedback: ({ caller, feedback }) => record(caller, feedback)
      }
    })
  })
});

mcpServer<Caller>({
  elicitation: { enabled: true },
  tools: () => ({
    book_table: {
      description: 'Book a table.',
      inputSchema: { type: 'object' },
      mayElicit: true, // opt in: this tool may ask
      handler: async (args, { canElicit, elicit }) => {
        if (!canElicit) return 'Tell me the party size first.';
        const answer = await elicit({
          message: 'How many people?',
          requestedSchema: {
            type: 'object',
            properties: { people: { type: 'integer', minimum: 1 } },
            required: ['people']
          }
        });
        if (answer.action !== 'accept') return 'No problem — cancelled.';

        return `Booked for ${answer.content.people}.`;
      }
    }
  })
});

elicitation: {
  enabled: true,
  // (1) The client initializes on A and calls a tool on B, which has
  //     never heard of the session. Put session state where every
  //     instance sees it. It is an id and a boolean — nothing
  //     sensitive, nothing large.
  store: {
    create: ({ canElicit }) => db.insertSession(canElicit), // → id
    get: (id) => db.findSession(id), // → { canElicit } | null
    drop: (id) => db.deleteSession(id)
  },
  // (2) The tool call and its question live on ONE instance, but the
  //     user's answer POST can land on any of them. A promise cannot
  //     move, so route the answer to the instance that is waiting —
  //     over whatever fan-out you already run (Postgres
  //     LISTEN/NOTIFY, Redis, ...).
  bus: {
    publish: (answer) => notify('mcp_elicit', answer),
    subscribe: (handler) => listen('mcp_elicit', handler)
  },
  // How long a question waits for a human before it gives up
  // (default 2 minutes).
  timeoutMs: 120000
}

import { createMcpClient } from '@absolutejs/mcp';

const client = createMcpClient({
  url: 'https://their.app/mcp',
  headers: { authorization: `Bearer ${accessToken}` },
  // Passing onElicit is what declares the elicitation capability —
  // omit it and servers are told you cannot ask anyone. Return
  // decline (the user said no) or cancel (they dismissed it);
  // NEVER fabricate content on the user's behalf.
  onElicit: async (request) => askTheUser(request)
});

await client.initialize();
const tools = await client.listTools(); // follows nextCursor paging
const result = await client.callTool('book_table', { people: 4 });