feat: add get_call_details tool

The existing get_call tool returns a summary projection (id, status,
endedReason, assistantId, phoneNumberId, customer.number, scheduledAt)
which makes it impossible to fetch transcripts, recordings, messages,
costs, or analysis without dropping out to the REST API.

This adds a sibling get_call_details tool that returns the full call
payload. It accepts an optional 'include' array so callers can scope
the response to specific fields (transcript, recordingUrl, messages,
costs, cost, analysis, summary, artifact) and keep LLM context windows
in check on long calls.

- New schemas: GetCallDetailsInputSchema, CallDetailsOutputSchema, CALL_DETAIL_FIELDS
- New transformer: transformCallDetailsOutput
- New tool registration in src/tools/call.ts
- E2E test updated to assert tool is registered

Author: nick-vapi

src/__tests__/mcp-server-e2e.test.ts

@@ -59,6 +59,7 @@ describe('MCP Server E2E Test', () => {
     expect(toolNames).toContain('list_calls');
     expect(toolNames).toContain('create_call');
     expect(toolNames).toContain('get_call');
+    expect(toolNames).toContain('get_call_details');
   });
 
   describe('Assistant Tools', () => {

src/schemas/index.ts

@@ -304,6 +304,38 @@ export const GetCallInputSchema = z.object({
   callId: z.string().describe('ID of the call to get'),
 });
 
+export const CALL_DETAIL_FIELDS = [
+  'transcript',
+  'recordingUrl',
+  'messages',
+  'costs',
+  'cost',
+  'analysis',
+  'summary',
+  'artifact',
+] as const;
+
+export const GetCallDetailsInputSchema = z.object({
+  callId: z.string().describe('ID of the call to get full details for'),
+  include: z
+    .array(z.enum(CALL_DETAIL_FIELDS))
+    .optional()
+    .describe(
+      'Subset of detail fields to return. Omit to return the full call object. Useful for keeping LLM context small on long calls.'
+    ),
+});
+
+export const CallDetailsOutputSchema = CallOutputSchema.extend({
+  transcript: z.string().optional(),
+  recordingUrl: z.string().optional(),
+  summary: z.string().optional(),
+  messages: z.array(z.any()).optional(),
+  costs: z.array(z.any()).optional(),
+  cost: z.number().optional(),
+  analysis: z.any().optional(),
+  artifact: z.any().optional(),
+});
+
 // ===== Phone Number Schemas =====
 
 export const GetPhoneNumberInputSchema = z.object({

src/tools/call.ts

@@ -1,10 +1,15 @@
 import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
 import { VapiClient, Vapi } from '@vapi-ai/server-sdk';
 
-import { CallInputSchema, GetCallInputSchema } from '../schemas/index.js';
+import {
+  CallInputSchema,
+  GetCallInputSchema,
+  GetCallDetailsInputSchema,
+} from '../schemas/index.js';
 import {
   transformCallInput,
   transformCallOutput,
+  transformCallDetailsOutput,
 } from '../transformers/index.js';
 import { createToolHandler } from './utils.js';
 
@@ -42,4 +47,14 @@ export const registerCallTools = (
       return transformCallOutput(call);
     })
   );
+
+  server.tool(
+    'get_call_details',
+    'Gets full details of a specific call (transcript, recording URL, messages, costs, analysis, summary, artifact). Use after get_call when summary fields are not enough. Pass `include` to scope the response and avoid blowing past LLM context windows on long calls.',
+    GetCallDetailsInputSchema.shape,
+    createToolHandler(async (data) => {
+      const call = await vapiClient.calls.get(data.callId);
+      return transformCallDetailsOutput(call, data.include);
+    })
+  );
 };

src/transformers/index.ts

@@ -10,6 +10,7 @@ import {
   UpdateAssistantInputSchema,
   CreateToolInputSchema,
   UpdateToolInputSchema,
+  CALL_DETAIL_FIELDS,
 } from '../schemas/index.js';
 
 // ===== Assistant Transformers =====
@@ -228,6 +229,29 @@ export function transformCallOutput(
   };
 }
 
+export function transformCallDetailsOutput(
+  call: Vapi.Call,
+  include?: ReadonlyArray<(typeof CALL_DETAIL_FIELDS)[number]>
+): Record<string, unknown> {
+  const summary = transformCallOutput(call);
+  const callRecord = call as unknown as Record<string, unknown>;
+  const artifact = (callRecord.artifact ?? {}) as Record<string, unknown>;
+
+  const fields = include ?? CALL_DETAIL_FIELDS;
+  const details: Record<string, unknown> = {};
+  for (const field of fields) {
+    const value = callRecord[field] ?? artifact[field];
+    if (value !== undefined) {
+      details[field] = value;
+    }
+  }
+
+  if (include) {
+    return { id: call.id, ...details };
+  }
+  return { ...summary, ...details };
+}
+
 // ===== Phone Number Transformers =====
 
 export function transformPhoneNumberOutput(