fix(browser): preserve distinct WebMCP declaration metadata (#2854)

* fix(browser): preserve distinct WebMCP declaration metadata

* test(browser): retain the first equivalent declaration location

src/domain/webBundleAnalyzer.test.ts

@@ -714,3 +714,54 @@ it("keeps RPC lexical identity and bundled factory recognition in captured scrip
   ]);
   expect(result.completeness.status).toBe("complete");
 });
+
+it("retains distinct WebMCP descriptions and names while deduplicating equivalent properties", () => {
+  const result = analyzeCapturedWebBundle(
+    inspection(`
+      document.modelContext.registerTool({ name: "lookup", description: "first", inputSchema: { properties: { alpha: {} } } });
+      document.modelContext.registerTool({ name: "lookup", description: "second", inputSchema: { properties: { alpha: {} } } });
+      document.modelContext.registerTool({ name: "equivalent", inputSchema: { properties: { alpha: {}, beta: {} } } });
+      document.modelContext.registerTool({ name: "equivalent", inputSchema: { properties: { beta: {}, alpha: {}, alpha: {} } } });
+      document.modelContext.registerTool({ description: "unnamed" });
+      document.modelContext.registerTool({ name: "", description: "unnamed" });
+    `),
+  );
+
+  expect(
+    result.observations.webmcp_declarations.map(
+      ({ name, description, schema_property_names }) => ({
+        name,
+        description,
+        schema_property_names,
+      }),
+    ),
+  ).toEqual([
+    {
+      name: "lookup",
+      description: "first",
+      schema_property_names: ["alpha"],
+    },
+    {
+      name: "lookup",
+      description: "second",
+      schema_property_names: ["alpha"],
+    },
+    {
+      name: "equivalent",
+      description: null,
+      schema_property_names: ["alpha", "beta"],
+    },
+    { name: null, description: "unnamed", schema_property_names: [] },
+    { name: "", description: "unnamed", schema_property_names: [] },
+  ]);
+  expect(result.observations.webmcp_declarations[2]?.location).toEqual({
+    script_key: `scr_${"1".repeat(64)}`,
+    line: 4,
+    column: 6,
+  });
+  expect(
+    result.observations.webmcp_declarations.every(
+      ({ trust }) => trust === "page-declared-untrusted",
+    ),
+  ).toBe(true);
+});

src/domain/webBundleAnalyzerInspection.ts

@@ -293,19 +293,18 @@ const addWebMcpDeclaration = (
           : [],
       )
     : [];
+  const metadata = {
+    name: name ?? null,
+    description: description ?? null,
+    schema_property_names: [...new Set(schemaPropertyNames)].sort(),
+  };
+  // Deduplicate the metadata we return, preserving omission and descriptions.
   // Property names are a variable-length source-derived list: NUL-joins
   // would collapse ["a\0b"] with ["a", "b"] and drop a declaration.
-  const key = compositeKey([
-    "webmcp",
-    script.script_key,
-    name ?? "",
-    schemaPropertyNames,
-  ]);
+  const key = compositeKey(["webmcp", script.script_key, metadata]);
   addUnique(accumulator, key, () =>
     accumulator.webMcp.push({
-      name: name ?? null,
-      description: description ?? null,
-      schema_property_names: [...new Set(schemaPropertyNames)].sort(),
+      ...metadata,
       trust: "page-declared-untrusted",
       location: location(script.script_key, node),
     }),