diff --git a/apps/config-builder/src/lib/validation.test.ts b/apps/config-builder/src/lib/validation.test.ts
new file mode 100644
index 000000000000..3d814dc3060a
--- /dev/null
+++ b/apps/config-builder/src/lib/validation.test.ts
@@ -0,0 +1,34 @@
+import { describe, expect, it } from "vitest";
+import { validateConfigDraft } from "./validation.ts";
+
+describe("validateConfigDraft", () => {
+  it("accepts empty drafts", () => {
+    const result = validateConfigDraft({});
+    expect(result.valid).toBe(true);
+    expect(result.issues).toHaveLength(0);
+  });
+
+  it("collects issues by path and section", () => {
+    const result = validateConfigDraft({
+      gateway: {
+        auth: {
+          token: 123,
+        },
+      },
+    });
+
+    expect(result.valid).toBe(false);
+    expect(result.issues.length).toBeGreaterThan(0);
+    expect(result.issuesByPath["gateway.auth.token"]?.length).toBeGreaterThan(0);
+    expect(result.sectionErrorCounts.gateway).toBeGreaterThan(0);
+  });
+
+  it("tracks root-level schema issues", () => {
+    const result = validateConfigDraft({
+      __unexpected__: true,
+    });
+
+    expect(result.valid).toBe(false);
+    expect(result.sectionErrorCounts.root).toBeGreaterThan(0);
+  });
+});
diff --git a/apps/config-builder/src/lib/validation.ts b/apps/config-builder/src/lib/validation.ts
new file mode 100644
index 000000000000..38198f46dee1
--- /dev/null
+++ b/apps/config-builder/src/lib/validation.ts
@@ -0,0 +1,73 @@
+import { OpenClawSchema } from "@openclaw/config/zod-schema.ts";
+import type { ConfigDraft } from "./config-store.ts";
+
+export type ValidationIssue = {
+  path: string;
+  section: string;
+  message: string;
+};
+
+export type ValidationResult = {
+  valid: boolean;
+  issues: ValidationIssue[];
+  issuesByPath: Record<string, string[]>;
+  sectionErrorCounts: Record<string, number>;
+};
+
+function issuePath(path: Array<string | number>): string {
+  if (path.length === 0) {
+    return "";
+  }
+  return path
+    .map((segment) => (typeof segment === "number" ? String(segment) : segment))
+    .join(".");
+}
+
+function issueSection(path: string): string {
+  if (!path) {
+    return "root";
+  }
+  const [section] = path.split(".");
+  return section?.trim() || "root";
+}
+
+export function validateConfigDraft(config: ConfigDraft): ValidationResult {
+  const parsed = OpenClawSchema.safeParse(config);
+  if (parsed.success) {
+    return {
+      valid: true,
+      issues: [],
+      issuesByPath: {},
+      sectionErrorCounts: {},
+    };
+  }
+
+  const issues: ValidationIssue[] = parsed.error.issues.map((issue) => {
+    const path = issuePath(issue.path);
+    return {
+      path,
+      section: issueSection(path),
+      message: issue.message,
+    };
+  });
+
+  const issuesByPath: Record<string, string[]> = {};
+  const sectionErrorCounts: Record<string, number> = {};
+
+  for (const issue of issues) {
+    const key = issue.path;
+    if (!issuesByPath[key]) {
+      issuesByPath[key] = [];
+    }
+    issuesByPath[key].push(issue.message);
+
+    sectionErrorCounts[issue.section] = (sectionErrorCounts[issue.section] ?? 0) + 1;
+  }
+
+  return {
+    valid: false,
+    issues,
+    issuesByPath,
+    sectionErrorCounts,
+  };
+}