diff --git a/CHANGELOG.md b/CHANGELOG.md
index 00e5f147e..a32e7de4f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -29,6 +29,7 @@ Docs: https://docs.clawd.bot
 - Model catalog: avoid caching import failures, log transient discovery errors, and keep partial results. (#1332) — thanks @dougvk.
 - Doctor: clarify plugin auto-enable hint text in the startup banner.
 - Gateway: clarify unauthorized handshake responses with token/password mismatch guidance.
+- Gateway: clarify connect/validation errors for gateway params. (#1347) — thanks @vignesh07.
 - Gateway: preserve restart wake routing + thread replies across restarts. (#1337) — thanks @John-Rood.
 - Gateway: reschedule per-agent heartbeats on config hot reload without restarting the runner.
 - Config: log invalid config issues once per run and keep invalid-config errors stackless.
diff --git a/src/gateway/protocol/index.test.ts b/src/gateway/protocol/index.test.ts
new file mode 100644
index 000000000..828951366
--- /dev/null
+++ b/src/gateway/protocol/index.test.ts
@@ -0,0 +1,65 @@
+import { describe, expect, it } from "vitest";
+import type { ErrorObject } from "ajv";
+
+import { formatValidationErrors } from "./index.js";
+
+const makeError = (overrides: Partial<ErrorObject>): ErrorObject => ({
+  keyword: "type",
+  instancePath: "",
+  schemaPath: "#/",
+  params: {},
+  message: "validation error",
+  ...overrides,
+});
+
+describe("formatValidationErrors", () => {
+  it("returns unknown validation error when missing errors", () => {
+    expect(formatValidationErrors(undefined)).toBe("unknown validation error");
+    expect(formatValidationErrors(null)).toBe("unknown validation error");
+  });
+
+  it("returns unknown validation error when errors list is empty", () => {
+    expect(formatValidationErrors([])).toBe("unknown validation error");
+  });
+
+  it("formats additionalProperties at root", () => {
+    const err = makeError({
+      keyword: "additionalProperties",
+      params: { additionalProperty: "token" },
+    });
+
+    expect(formatValidationErrors([err])).toBe("at root: unexpected property 'token'");
+  });
+
+  it("formats additionalProperties with instancePath", () => {
+    const err = makeError({
+      keyword: "additionalProperties",
+      instancePath: "/auth",
+      params: { additionalProperty: "token" },
+    });
+
+    expect(formatValidationErrors([err])).toBe("at /auth: unexpected property 'token'");
+  });
+
+  it("formats message with path for other errors", () => {
+    const err = makeError({
+      keyword: "required",
+      instancePath: "/auth",
+      message: "must have required property 'token'",
+    });
+
+    expect(formatValidationErrors([err])).toBe("at /auth: must have required property 'token'");
+  });
+
+  it("de-dupes repeated entries", () => {
+    const err = makeError({
+      keyword: "required",
+      instancePath: "/auth",
+      message: "must have required property 'token'",
+    });
+
+    expect(formatValidationErrors([err, err])).toBe(
+      "at /auth: must have required property 'token'",
+    );
+  });
+});
diff --git a/src/gateway/protocol/index.ts b/src/gateway/protocol/index.ts
index 7d82e0ecc..dba040fe5 100644
--- a/src/gateway/protocol/index.ts
+++ b/src/gateway/protocol/index.ts
@@ -310,7 +310,7 @@ export const validateWebLoginStartParams =
 export const validateWebLoginWaitParams = ajv.compile<WebLoginWaitParams>(WebLoginWaitParamsSchema);
 
 export function formatValidationErrors(errors: ErrorObject[] | null | undefined) {
-  if (!errors) return "unknown validation error";
+  if (!errors?.length) return "unknown validation error";
 
   const parts: string[] = [];
 
@@ -328,13 +328,18 @@ export function formatValidationErrors(errors: ErrorObject[] | null | undefined)
       }
     }
 
-    const message = typeof err?.message === "string" ? err.message : "validation error";
+    const message =
+      typeof err?.message === "string" && err.message.trim() ? err.message : "validation error";
     const where = instancePath ? `at ${instancePath}: ` : "";
     parts.push(`${where}${message}`);
   }
 
   // De-dupe while preserving order.
-  const unique = Array.from(new Set(parts));
+  const unique = Array.from(new Set(parts.filter((part) => part.trim())));
+  if (!unique.length) {
+    const fallback = ajv.errorsText(errors, { separator: "; " });
+    return fallback || "unknown validation error";
+  }
   return unique.join("; ");
 }