diff --git a/CHANGELOG.md b/CHANGELOG.md
index 907e297..35c097c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,13 @@ All notable changes to this project are documented here. The format is based on
 [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) and this project adheres
 to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- Reject non-array `tools` fields in static manifests before auditing, with an
+  error identifying the source file.
+
 ## [0.1.1] - 2026-08-06
 
 ### Changed
diff --git a/src/static/manifest.ts b/src/static/manifest.ts
index f846c5f..ed2f136 100644
--- a/src/static/manifest.ts
+++ b/src/static/manifest.ts
@@ -52,6 +52,10 @@ export function normalize(parsed: unknown, source: string): AuditTarget {
     ? { tools: parsed as ToolSpec[] }
     : ((parsed as ManifestFile) ?? {});
 
+  if (manifest.tools != null && !Array.isArray(manifest.tools)) {
+    throw new Error(`Invalid manifest ${source}: tools must be an array.`);
+  }
+
   const serverInfo = manifest.serverInfo ?? manifest.server ?? {};
   const declaredHttp = manifest.transport === "http";
 
diff --git a/test/static.test.ts b/test/static.test.ts
index 18b593d..3507ca9 100644
--- a/test/static.test.ts
+++ b/test/static.test.ts
@@ -36,6 +36,22 @@ describe("loadManifest", () => {
     expect(target.transport).toBe("static");
   });
 
+  it.each(["MCP001", { name: "read_file" }, 42, true])(
+    "rejects a non-array tools field: %j",
+    (tools) => {
+      expect(() => normalize({ tools }, "invalid-tools.json")).toThrow(
+        "Invalid manifest invalid-tools.json: tools must be an array.",
+      );
+    },
+  );
+
+  it.each([{}, { tools: null }, { tools: [] }])(
+    "keeps an absent or empty tool list valid: %j",
+    (manifest) => {
+      expect(normalize(manifest, "empty.json").tools).toEqual([]);
+    },
+  );
+
   it("rejects a missing manifest file", async () => {
     await expect(loadManifest(resolve(root, "does-not-exist.json"))).rejects.toBeTruthy();
   });