test: fix all test type errors and typecheck tests in CI

.github/workflows/test.yml

@@ -26,5 +26,8 @@ jobs:
       - name: Compile typescript
         run: npm run build
 
+      - name: Typecheck src and tests
+        run: npm run typecheck
+
       - name: Run tests
         run: npm test

CHANGELOG.md

@@ -28,6 +28,9 @@
 ### Maintenance
 
 - **Removed build output committed under `src/` (#297).** `src/utils/versionUtils-cjs.cjs`, `.d.cts` and their source maps were compiled output from a `tsc` run that wrote next to the sources, committed back in #96. Only `versionUtils-cjs.cts` is source: tshy swaps it in for `versionUtils.ts` in the CommonJS build. `.gitignore` now keeps `.js`, `.cjs`, `.mjs`, `.d.*ts` and `.map` files out of `src/` and `test/`.
+- **Tests are typechecked in CI (#298).** `tsconfig.test.json` covers `src/` and `test/`, but nothing ran it, so test type errors piled up: about 200 on main, plus about 250 more from SDK v2 typing `structuredContent` as an open object (#296). They're all fixed, and `npm run typecheck` now runs in CI before the tests. `tsconfig.test.json` also gets `noEmit`, since running it without that writes `.js` files next to the sources (see #297).
+  - **New helpers** in `test/utils/resultTestUtils.ts`: `structuredOf<ToolOutput>(result)` reads structured content as the tool's own output type, so a test that checks a field the schema doesn't have fails to compile. `textOf` and `resourceTextOf` read text content and throw on the wrong content type.
+  - **Tests that were wrong:** the tuple check in `input-schema-validation.test.ts` never looked inside arrays under zod 4 (`ZodArray._def.type` is now the string `'array'`), so a tuple nested in an array would have passed. It uses zod 4's accessors now and covers that case. `structured-content.test.ts` imported a file that never existed. `cleanResponseData.test.ts` used an old directions input shape and now builds it with `DirectionsInputSchema.parse`. A `|| Infinity` fallback in a SimplifyTool test meant one comparison could never fail.
 
 ## 0.16.1-dev - 2026-10-16
 

package.json

@@ -18,6 +18,7 @@
     "inspect:build": "npm run build && npx @modelcontextprotocol/inspector -e MAPBOX_ACCESS_TOKEN=\"$MAPBOX_ACCESS_TOKEN\" node dist/esm/index.js",
     "inspect:dev": "npx @modelcontextprotocol/inspector -e MAPBOX_ACCESS_TOKEN=\"$MAPBOX_ACCESS_TOKEN\" npx -y tsx src/index.ts",
     "dev:http": "npx -y tsx scripts/dev-http-server.ts",
+    "typecheck": "tsc -p tsconfig.test.json",
     "lint": "eslint \"./src/**/*.{ts,tsx}\" \"./test/**/*.{ts,tsx}\" \"./examples/**/*.{ts,tsx}\"",
     "lint:fix": "eslint \"./src/**/*.{ts,tsx}\" \"./test/**/*.{ts,tsx}\" \"./examples/**/*.{ts,tsx}\" --fix",
     "postinstall": "patch-package || (cd ../../.. && node ./node_modules/patch-package/index.js --patch-dir ./node_modules/@mapbox/mcp-server/patches) || true",

test/prompts/BasePrompt.test.ts

@@ -8,8 +8,23 @@ import type {
   PromptMessage
 } from '@modelcontextprotocol/server';
 
+// Makes validateArguments public so tests can call it directly.
+abstract class TestableBasePrompt extends BasePrompt {
+  override validateArguments(args: Record<string, string>): void {
+    super.validateArguments(args);
+  }
+}
+
+// The text of a prompt message. Throws if the content isn't text.
+function messageText(message: PromptMessage): string {
+  if (message.content.type !== 'text') {
+    throw new Error(`message content is ${message.content.type}, not text`);
+  }
+  return message.content.text;
+}
+
 // Create a concrete test implementation of BasePrompt
-class TestPrompt extends BasePrompt {
+class TestPrompt extends TestableBasePrompt {
   readonly name = 'test-prompt';
   readonly description = 'A test prompt for unit testing';
   readonly arguments: PromptArgument[] = [
@@ -173,7 +188,7 @@ describe('BasePrompt', () => {
         expect(message.role).toBeDefined();
         expect(message.content).toBeDefined();
         expect(message.content.type).toBe('text');
-        expect(typeof message.content.text).toBe('string');
+        expect(typeof messageText(message)).toBe('string');
       });
     });
 
@@ -194,10 +209,10 @@ describe('BasePrompt', () => {
       };
 
       const messages = prompt.getMessages(args);
-      const messageText = messages[0].content.text;
+      const text = messageText(messages[0]);
 
-      expect(messageText).toContain('test_required');
-      expect(messageText).toContain('test_optional');
+      expect(text).toContain('test_required');
+      expect(text).toContain('test_optional');
     });
 
     test('handles missing optional arguments gracefully', () => {
@@ -206,16 +221,16 @@ describe('BasePrompt', () => {
       };
 
       const messages = prompt.getMessages(args);
-      const messageText = messages[0].content.text;
+      const text = messageText(messages[0]);
 
-      expect(messageText).toContain('test_required');
-      expect(messageText).toContain('not provided');
+      expect(text).toContain('test_required');
+      expect(text).toContain('not provided');
     });
   });
 
   describe('edge cases', () => {
     test('validates empty args object when no arguments are required', () => {
-      class NoArgsPrompt extends BasePrompt {
+      class NoArgsPrompt extends TestableBasePrompt {
         readonly name = 'no-args';
         readonly description = 'No arguments needed';
         readonly arguments: PromptArgument[] = [];
@@ -239,7 +254,7 @@ describe('BasePrompt', () => {
     });
 
     test('validates all required arguments', () => {
-      class MultiRequiredPrompt extends BasePrompt {
+      class MultiRequiredPrompt extends TestableBasePrompt {
         readonly name = 'multi-required';
         readonly description = 'Multiple required arguments';
         readonly arguments: PromptArgument[] = [

test/resources/category-list/CategoryListResource.test.ts

@@ -9,6 +9,7 @@ import {
   assertHeadersSent
 } from '../../utils/httpPipelineUtils.js';
 import { CategoryListResource } from '../../../src/resources/category-list/CategoryListResource.js';
+import { resourceTextOf } from '../../utils/resultTestUtils.js';
 
 describe('CategoryListResource', () => {
   afterEach(() => {
@@ -111,7 +112,7 @@ describe('CategoryListResource', () => {
     expect(result.contents[0].uri).toBe('mapbox://categories');
     expect(result.contents[0].mimeType).toBe('application/json');
 
-    const parsed = JSON.parse(result.contents[0].text!);
+    const parsed = JSON.parse(resourceTextOf(result));
     expect(parsed.listItems).toEqual(['restaurant', 'hotel']);
     expect(parsed.version).toBe('25:test');
     expect(parsed.attribution).toBe('Test Attribution');
@@ -131,7 +132,7 @@ describe('CategoryListResource', () => {
     );
 
     expect(result.contents).toHaveLength(1);
-    const parsed = JSON.parse(result.contents[0].text!);
+    const parsed = JSON.parse(resourceTextOf(result));
     expect(parsed.listItems).toEqual([]);
   });
 

test/resources/compute/ComputeResource.test.ts

@@ -4,6 +4,7 @@
 import { describe, it, expect } from 'vitest';
 import { ComputeResource } from '../../../src/resources/compute/ComputeResource.js';
 import { buildComputeRef } from '../../../src/utils/computeRef.js';
+import { resourceTextOf } from '../../utils/resultTestUtils.js';
 
 describe('ComputeResource', () => {
   it('resolves a union compute ref via the real resources/read path with zero prior server-side state', async () => {
@@ -47,7 +48,7 @@ describe('ComputeResource', () => {
     const result = await resource.read(ref);
 
     expect(result.contents[0].mimeType).toBe('application/json');
-    const payload = JSON.parse(result.contents[0].text as string);
+    const payload = JSON.parse(resourceTextOf(result));
     expect(payload.layers).toHaveLength(6);
     expect(payload.summary).toBe('Union of 2 polygons');
   });
@@ -90,7 +91,7 @@ describe('ComputeResource', () => {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     const asAccountB = { http: { authInfo: { token: 'irrelevant' } } } as any;
     const result = await resource.read(ref, asAccountB);
-    const payload = JSON.parse(result.contents[0].text as string);
+    const payload = JSON.parse(resourceTextOf(result));
     expect(payload.summary).toBe('Intersection of two polygons');
   });
 
@@ -99,6 +100,6 @@ describe('ComputeResource', () => {
     const result = await resource.read('mapbox://compute/union?data=!!!');
 
     expect(result.contents[0].mimeType).toBe('text/plain');
-    expect(result.contents[0].text).toContain('malformed or unsupported');
+    expect(resourceTextOf(result)).toContain('malformed or unsupported');
   });
 });

test/resources/inline-payload/InlinePayloadResource.test.ts

@@ -4,6 +4,7 @@
 import { describe, it, expect } from 'vitest';
 import { InlinePayloadResource } from '../../../src/resources/inline-payload/InlinePayloadResource.js';
 import { buildInlinePayloadRef } from '../../../src/utils/inlinePayloadRef.js';
+import { resourceTextOf } from '../../utils/resultTestUtils.js';
 
 describe('InlinePayloadResource', () => {
   it("resolves render_map_tool's self-describing merged ref via the real resources/read path with zero prior server-side state", async () => {
@@ -33,7 +34,7 @@ describe('InlinePayloadResource', () => {
     const result = await resource.read(ref);
 
     expect(result.contents[0].mimeType).toBe('application/json');
-    const payload = JSON.parse(result.contents[0].text as string);
+    const payload = JSON.parse(resourceTextOf(result));
     expect(payload.summary).toBe('Test trip');
     expect(payload.layers).toHaveLength(1);
     expect(payload.markers).toHaveLength(1);
@@ -44,6 +45,6 @@ describe('InlinePayloadResource', () => {
     const result = await resource.read('mapbox://inline/payload?data=!!!');
 
     expect(result.contents[0].mimeType).toBe('text/plain');
-    expect(result.contents[0].text).toContain('malformed');
+    expect(resourceTextOf(result)).toContain('malformed');
   });
 });

test/resources/temporary/TemporaryDataResource.test.ts

@@ -12,6 +12,15 @@ import {
   getOwnerKeyFromToken,
   getUserNameFromToken
 } from '../../../src/utils/jwtUtils.js';
+import type { ReadResourceResult } from '@modelcontextprotocol/server';
+import { resourceTextOf } from '../../utils/resultTestUtils.js';
+
+// The blob of a resource read's first contents entry, or undefined when
+// it's text.
+function blobOf(result: ReadResourceResult): string | undefined {
+  const entry = result.contents[0];
+  return 'blob' in entry ? entry.blob : undefined;
+}
 
 // Build a Mapbox-style 3-part JWT whose payload carries the username (`u`).
 function tokenFor(username: string): string {
@@ -82,7 +91,7 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
     seedTextResource(uri, 'accountA', { route: 'A-secret-geometry' });
 
     const result = await resource.read(uri, extraFor(tokenFor('accountA')));
-    const text = result.contents[0].text as string;
+    const text = resourceTextOf(result);
 
     expect(text).toContain('A-secret-geometry');
   });
@@ -92,7 +101,7 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
     seedTextResource(uri, 'accountA', { route: 'A-secret-geometry' });
 
     const result = await resource.read(uri, extraFor(tokenFor('accountB')));
-    const text = result.contents[0].text as string;
+    const text = resourceTextOf(result);
 
     expect(text).toBe(NOT_FOUND);
     expect(text).not.toContain('A-secret-geometry');
@@ -117,16 +126,16 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
     expect(crossAccount.contents[0].mimeType).toBe(
       missing.contents[0].mimeType
     );
-    expect(crossAccount.contents[0].text).toBe(missing.contents[0].text);
-    expect(crossAccount.contents[0].text).toBe(NOT_FOUND);
+    expect(resourceTextOf(crossAccount)).toBe(resourceTextOf(missing));
+    expect(resourceTextOf(crossAccount)).toBe(NOT_FOUND);
   });
 
   it('fails closed when the reader has no token', async () => {
     const uri = 'mapbox://temp/directions-ddd';
     seedTextResource(uri, 'accountA', { route: 'A-secret-geometry' });
 
     const result = await resource.read(uri, extraFor(undefined));
-    expect(result.contents[0].text).toBe(NOT_FOUND);
+    expect(resourceTextOf(result)).toBe(NOT_FOUND);
   });
 
   it('fails closed when the resource has no owner recorded', async () => {
@@ -139,7 +148,7 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
     });
 
     const result = await resource.read(uri, extraFor(tokenFor('accountA')));
-    expect(result.contents[0].text).toBe(NOT_FOUND);
+    expect(resourceTextOf(result)).toBe(NOT_FOUND);
   });
 
   it('falls back to the env token so stdio/single-user reads still work', async () => {
@@ -150,7 +159,7 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
 
     // No authInfo on the request (stdio) -> requester resolved from env token.
     const result = await resource.read(uri, extraFor(undefined));
-    expect(result.contents[0].text as string).toContain('local-data');
+    expect(resourceTextOf(result)).toContain('local-data');
   });
 
   it('returns image blobs to the owner and not-found to others', async () => {
@@ -165,12 +174,12 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
     });
 
     const owner = await resource.read(uri, extraFor(tokenFor('accountA')));
-    expect(owner.contents[0].blob).toBe('BASE64IMAGEDATA');
+    expect(blobOf(owner)).toBe('BASE64IMAGEDATA');
     expect(owner.contents[0].mimeType).toBe('image/png');
 
     const other = await resource.read(uri, extraFor(tokenFor('accountB')));
-    expect(other.contents[0].blob).toBeUndefined();
-    expect(other.contents[0].text).toBe(NOT_FOUND);
+    expect(blobOf(other)).toBeUndefined();
+    expect(resourceTextOf(other)).toBe(NOT_FOUND);
   });
 
   it('resolves a storeMapPayload ref via the real resources/read path (regression)', async () => {
@@ -185,7 +194,7 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
     );
 
     const result = await resource.read(ref, extraFor(tokenFor('accountA')));
-    const parsed = JSON.parse(result.contents[0].text as string);
+    const parsed = JSON.parse(resourceTextOf(result));
 
     expect(parsed.summary).toBe('Test route');
   });
@@ -210,8 +219,8 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
 
     const result = await resource.read(uri, extraFor(forged));
 
-    expect(result.contents[0].text).toBe(NOT_FOUND);
-    expect(result.contents[0].text).not.toContain('A-secret-geometry');
+    expect(resourceTextOf(result)).toBe(NOT_FOUND);
+    expect(resourceTextOf(result)).not.toContain('A-secret-geometry');
   });
 
   it('does NOT return an image blob to a token forging the owner’s username', async () => {
@@ -230,8 +239,8 @@ describe('TemporaryDataResource — AGI-890 cross-account access control', () =>
       extraFor(forgedTokenFor('victim_user'))
     );
 
-    expect(result.contents[0].blob).toBeUndefined();
-    expect(result.contents[0].text).toBe(NOT_FOUND);
+    expect(blobOf(result)).toBeUndefined();
+    expect(resourceTextOf(result)).toBe(NOT_FOUND);
   });
 
   it('does NOT resolve a map-payload ref for a token forging the owner’s username', async () => {

test/resources/ui-apps/MapAppUIResource.test.ts

@@ -7,6 +7,8 @@ const SK_TOKEN = 'sk.eyJzdWIiOiJ0ZXN0IiwidSI6InRlc3R1c2VyIn0.signature';
 import { describe, it, expect, afterEach, beforeEach, vi } from 'vitest';
 import { MapAppUIResource } from '../../../src/resources/ui-apps/MapAppUIResource.js';
 import { __resetMapboxPublicTokenCache } from '../../../src/utils/mapboxPublicToken.js';
+import { resourceTextOf } from '../../utils/resultTestUtils.js';
+import type { HttpRequest } from '../../../src/utils/types.js';
 
 const fakeTokenList = [
   {
@@ -39,7 +41,8 @@ describe('MapAppUIResource', () => {
   });
 
   it('serves HTML at ui://mapbox/map-app/index.html with the mcp-app mime type', async () => {
-    const httpRequest = vi.fn(async (url: string) => {
+    const httpRequest = vi.fn<HttpRequest>(async (input) => {
+      const url = String(input);
       if (url.includes('tokens/v2/'))
         return makeOkJson(fakeTokenList) as Response;
       throw new Error(`Unexpected URL: ${url}`);
@@ -57,11 +60,10 @@ describe('MapAppUIResource', () => {
     const entry = result.contents[0];
     expect(entry.mimeType).toBe('text/html;profile=mcp-app');
     expect(entry.uri).toBe('ui://mapbox/map-app/index.html');
-    expect(typeof entry.text).toBe('string');
-    expect(entry.text as string).toContain(
-      'pk.eyJ1IjoidGVzdHVzZXIifQ.fake-public-token'
-    );
-    expect(entry.text as string).toContain('mapbox-gl.js');
+    const text = resourceTextOf(result);
+    expect(typeof text).toBe('string');
+    expect(text).toContain('pk.eyJ1IjoidGVzdHVzZXIifQ.fake-public-token');
+    expect(text).toContain('mapbox-gl.js');
 
     const meta = (entry as { _meta?: unknown })._meta as
       | { ui?: { csp?: Record<string, string[]> } }
@@ -86,7 +88,7 @@ describe('MapAppUIResource', () => {
       // eslint-disable-next-line @typescript-eslint/no-explicit-any
     } as any);
 
-    expect(result.contents[0].text as string).toContain(
+    expect(resourceTextOf(result)).toContain(
       'No Mapbox public token available'
     );
   });