feat: isochrone_tool renders as a live GL JS map (MCP Apps + MCP-UI)

CHANGELOG.md

@@ -17,6 +17,7 @@
 
 ### New Features
 
+- **`isochrone_tool` now renders as a live Mapbox GL JS map** following the same dual-spec pattern as `directions_tool`: MCP Apps via `_meta.ui.resourceUri` → `IsochroneAppUIResource`, plus an inline MCP-UI rawHtml block (gated by `ENABLE_MCP_UI`). One shared `renderIsochroneAppHtml` template renders the contours as translucent fill + outline layers with the origin marked.
 - **`directions_tool` now renders as a live Mapbox GL JS map** for both the MCP Apps spec and legacy MCP-UI clients:
   - **MCP Apps**: the tool declares `_meta.ui.resourceUri` pointing to a new `DirectionsAppUIResource` (`ui://mapbox/directions-app/index.html`). MCP App–capable hosts (Claude Desktop, VS Code, Cursor) render the route via postMessage handoff.
   - **MCP-UI**: when `geometries=geojson` is requested and the response carries a renderable LineString, an inline `rawHtml` UIResource is added to the tool's `content[]` (gated by the existing `ENABLE_MCP_UI`/`--disable-mcp-ui` flag, like `static_map_image_tool`).

src/resources/resourceRegistry.ts

@@ -6,6 +6,7 @@ import { CategoryListResource } from './category-list/CategoryListResource.js';
 import { TemporaryDataResource } from './temporary/TemporaryDataResource.js';
 import { StaticMapUIResource } from './ui-apps/StaticMapUIResource.js';
 import { DirectionsAppUIResource } from './ui-apps/DirectionsAppUIResource.js';
+import { IsochroneAppUIResource } from './ui-apps/IsochroneAppUIResource.js';
 import { VersionResource } from './version/VersionResource.js';
 import { httpRequest } from '../utils/httpPipeline.js';
 
@@ -16,6 +17,7 @@ export const ALL_RESOURCES = [
   new TemporaryDataResource(),
   new StaticMapUIResource(),
   new DirectionsAppUIResource({ httpRequest }),
+  new IsochroneAppUIResource({ httpRequest }),
   new VersionResource()
 ] as const;
 

src/resources/ui-apps/IsochroneAppUIResource.ts

@@ -0,0 +1,83 @@
+// Copyright (c) Mapbox, Inc.
+// Licensed under the MIT License.
+
+import type { RequestHandlerExtra } from '@modelcontextprotocol/sdk/shared/protocol.js';
+import type {
+  ReadResourceResult,
+  ServerNotification,
+  ServerRequest
+} from '@modelcontextprotocol/sdk/types.js';
+import { RESOURCE_MIME_TYPE } from '@modelcontextprotocol/ext-apps/server';
+import { BaseResource } from '../BaseResource.js';
+import type { HttpRequest } from '../../utils/types.js';
+import { resolveMapboxPublicToken } from '../../utils/mapboxPublicToken.js';
+import { renderIsochroneAppHtml } from './isochroneAppHtml.js';
+
+/**
+ * MCP Apps resource for `isochrone_tool` — serves the HTML at
+ * `ui://mapbox/isochrone-app/index.html`. The iframe receives the tool's
+ * FeatureCollection via the `ui/notifications/tool-result` postMessage event
+ * and renders each contour as a translucent fill + outline layer.
+ */
+export class IsochroneAppUIResource extends BaseResource {
+  readonly name = 'Isochrone App UI';
+  readonly uri = 'ui://mapbox/isochrone-app/index.html';
+  readonly description =
+    'Interactive UI for visualizing Mapbox isochrone contours with Mapbox GL JS (MCP Apps)';
+  readonly mimeType = RESOURCE_MIME_TYPE;
+
+  private readonly httpRequest: HttpRequest;
+  private readonly apiEndpoint: () => string;
+
+  constructor(params: {
+    httpRequest: HttpRequest;
+    apiEndpoint?: () => string;
+  }) {
+    super();
+    this.httpRequest = params.httpRequest;
+    this.apiEndpoint =
+      params.apiEndpoint ??
+      (() => process.env.MAPBOX_API_ENDPOINT || 'https://api.mapbox.com/');
+  }
+
+  async read(
+    _uri: string,
+    extra?: RequestHandlerExtra<ServerRequest, ServerNotification>
+  ): Promise<ReadResourceResult> {
+    const accessToken =
+      (extra?.authInfo?.token as string | undefined) ||
+      process.env.MAPBOX_ACCESS_TOKEN ||
+      '';
+
+    const publicToken = await resolveMapboxPublicToken({
+      accessToken,
+      apiEndpoint: this.apiEndpoint(),
+      httpRequest: this.httpRequest
+    });
+
+    const html = renderIsochroneAppHtml({ publicToken: publicToken ?? '' });
+
+    return {
+      contents: [
+        {
+          uri: this.uri,
+          mimeType: RESOURCE_MIME_TYPE,
+          text: html,
+          _meta: {
+            ui: {
+              csp: {
+                connectDomains: [
+                  'https://*.mapbox.com',
+                  'https://events.mapbox.com'
+                ],
+                resourceDomains: ['https://api.mapbox.com'],
+                workerDomains: ['blob:']
+              },
+              preferredSize: { width: 1000, height: 600 }
+            }
+          }
+        }
+      ]
+    };
+  }
+}