diff --git a/.gitignore b/.gitignore
index 4ed3edc1..3f844610 100644
--- a/.gitignore
+++ b/.gitignore
@@ -87,3 +87,8 @@ target-linux/
 # once committed three of these, 7.9 MB, into a feature branch).
 *.bundle
 *.gitbundle
+
+# Extension marketplace local registry and validation scratch
+marketplace/.data/
+validation-results/
+.qa/
diff --git a/__tests__/extension-explore.test.ts b/__tests__/extension-explore.test.ts
new file mode 100644
index 00000000..eb31bb4f
--- /dev/null
+++ b/__tests__/extension-explore.test.ts
@@ -0,0 +1,34 @@
+import { afterEach, expect, it } from 'vitest';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+import { CodeGraph } from '../src';
+import { ExtensionManager } from '../src/plugins/manager';
+import { ToolHandler } from '../src/mcp/tools';
+import { findAllSymbols, flowTokens } from '../src/graph/named-symbol-flow';
+const roots: string[] = [];
+afterEach(() => roots.splice(0).forEach(root => fs.rmSync(root, { recursive: true, force: true })));
+it('surfaces exact extension route-to-handler flow and its author label', async () => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-extension-explore-')); roots.push(root);
+  fs.writeFileSync(path.join(root, 'app.ts'), 'export function checkout() { return 1; }\n');
+  const bytes = Buffer.from(JSON.stringify({ format: 'codegraph-extension-1', package: {
+    name: '@test/routes', version: '1.0.0', main: 'index.cjs', codegraph: { id: 'routes', apiVersion: 1, capabilities: ['frameworks', 'synthPasses'] },
+  }, files: { 'index.cjs': `module.exports=()=>({frameworks:[{name:'routes',languages:['typescript'],detect:()=>true,resolve:()=>null,
+    extract(file){return {nodes:[{id:'plugin:routes:checkout',kind:'route',name:'/checkout/{order}',qualifiedName:file+'::checkout-route',filePath:file,language:'typescript',startLine:1,endLine:1,startColumn:0,endColumn:0,updatedAt:0}],references:[]}}}],
+    synthPasses:[{name:'flow',languages:['typescript'],async run(ctx){return [{source:'plugin:routes:checkout',target:ctx.getNodesByName('checkout')[0].id,kind:'calls',metadata:{label:'Example route handler',registeredAt:'app.ts:1'}}]}}]});` } }));
+  await new ExtensionManager(root).install({ bytes });
+  const graph = await CodeGraph.open(root);
+  try {
+    const response = await new ToolHandler(graph).execute('codegraph_explore', { query: '/checkout/{order} checkout' });
+    const text = response.content?.[0]?.text || '';
+    expect(text).toContain('/checkout/{order} → checkout');
+    expect(text).toContain('Example route handler');
+    expect(text).toContain('app.ts:1');
+    expect(findAllSymbols(graph, '/missing').nodes).toEqual([]);
+    expect(findAllSymbols(graph, '/checkout').nodes).toEqual([]);
+    expect(findAllSymbols(graph, '/checkout/{order}').nodes.map(n => n.kind)).toEqual(['route']);
+  } finally { graph.close(); }
+}, 30_000);
+it('preserves literal route paths, placeholders and filename-shaped endpoints', () => {
+  expect(flowTokens('/ /users/{user} /health.php Controller.handle https://example.com')).toEqual(['/', '/users/{user}', '/health.php', 'Controller.handle']);
+});