fix(gateway): handle malformed tool payload validation safely

CHANGELOG.md

@@ -35,6 +35,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Gateway/tools invoke malformed-tool hardening: classify tool schema validation failures (including Zod-style errors) as controlled `400 tool_error` responses instead of internal failures, preventing malformed tool payloads from escalating into unstable runtime behavior. (#38384)
 - Onboarding/headless Linux daemon probe hardening: treat `systemctl --user is-enabled` probe failures as non-fatal during daemon install flow so onboarding no longer crashes on SSH/headless VPS environments before showing install guidance. (#37297) Thanks @acarbajal-web.
 - Memory/QMD mcporter Windows spawn hardening: when `mcporter.cmd` launch fails with `spawn EINVAL`, retry via bare `mcporter` shell resolution so QMD recall can continue instead of falling back to builtin memory search. (#27402) Thanks @i0ivi0i.
 - Tools/web_search Brave language-code validation: align `search_lang` handling with Brave-supported codes (including `zh-hans`, `zh-hant`, `en-gb`, and `pt-br`), map common alias inputs (`zh`, `ja`) to valid Brave values, and reject unsupported codes before upstream requests to prevent 422 failures. (#37260) Thanks @heyanming.

src/gateway/tools-invoke-http.test.ts

@@ -117,6 +117,12 @@ vi.mock("../agents/openclaw-tools.js", () => {
         if (mode === "auth") {
           throw toolAuthorizationError("mode forbidden");
         }
+        if (mode === "zod") {
+          const err = new Error("invalid tool payload") as Error & { issues?: unknown[] };
+          err.name = "ZodError";
+          err.issues = [{ path: ["amount"], message: "Required", code: "invalid_type" }];
+          throw err;
+        }
         if (mode === "crash") {
           throw new Error("boom");
         }
@@ -540,7 +546,7 @@ describe("POST /tools/invoke", () => {
     expect(resMain.status).toBe(200);
   });
 
-  it("maps tool input/auth errors to 400/403 and unexpected execution errors to 500", async () => {
+  it("maps tool input/auth/schema errors to 400/403 and unexpected execution errors to 500", async () => {
     cfg = {
       ...cfg,
       agents: {
@@ -570,6 +576,17 @@ describe("POST /tools/invoke", () => {
     expect(authBody.error?.type).toBe("tool_error");
     expect(authBody.error?.message).toBe("mode forbidden");
 
+    const zodRes = await invokeToolAuthed({
+      tool: "tools_invoke_test",
+      args: { mode: "zod" },
+      sessionKey: "main",
+    });
+    expect(zodRes.status).toBe(400);
+    const zodBody = await zodRes.json();
+    expect(zodBody.ok).toBe(false);
+    expect(zodBody.error?.type).toBe("tool_error");
+    expect(zodBody.error?.message).toBe("invalid tool payload");
+
     const crashRes = await invokeToolAuthed({
       tool: "tools_invoke_test",
       args: { mode: "crash" },

src/gateway/tools-invoke-http.ts

@@ -117,6 +117,14 @@ function resolveToolInputErrorStatus(err: unknown): number | null {
     const status = (err as { status?: unknown }).status;
     return typeof status === "number" ? status : 400;
   }
+  // Some tool implementations throw raw ZodError objects on malformed model/tool payloads.
+  // Treat these as user-input validation failures (400), not internal server failures (500).
+  if (typeof err === "object" && err !== null) {
+    const record = err as { name?: unknown; issues?: unknown };
+    if (record.name === "ZodError" && Array.isArray(record.issues)) {
+      return 400;
+    }
+  }
   if (typeof err !== "object" || err === null || !("name" in err)) {
     return null;
   }