diff --git a/src/lib/error-reporting.ts b/src/lib/error-reporting.ts
index ac145c6e5..15ddb015e 100644
--- a/src/lib/error-reporting.ts
+++ b/src/lib/error-reporting.ts
@@ -50,6 +50,7 @@ type SilenceReason =
   | "output_error"
   | "context_missing"
   | "auth_expected"
+  | "validation_error"
   | "api_user_error"
   | "api_query_error"
   | "network_error";
@@ -91,6 +92,13 @@ export function classifySilenced(error: unknown): SilenceReason | null {
   if (error instanceof AuthError) {
     return "auth_expected";
   }
+  // A ValidationError means the user supplied malformed input (e.g. a project
+  // slug where a 32-char hex trace ID was required). It is never a CLI bug —
+  // the CLI correctly rejects the input and displays an actionable message.
+  // Silence it so it does not pollute Sentry as an unhandled error (CLI-1GP).
+  if (error instanceof ValidationError) {
+    return "validation_error";
+  }
   if (error instanceof ApiError && error.status > 400 && error.status < 500) {
     return "api_user_error";
   }
diff --git a/test/lib/error-reporting.test.ts b/test/lib/error-reporting.test.ts
index 75582ded8..aa3250945 100644
--- a/test/lib/error-reporting.test.ts
+++ b/test/lib/error-reporting.test.ts
@@ -308,12 +308,17 @@ describe("classifySilenced", () => {
     expect(classifySilenced(err)).toBe("context_missing");
   });
 
+  test("silences ValidationError (user-supplied malformed input)", () => {
+    expect(classifySilenced(new ValidationError("bad"))).toBe(
+      "validation_error",
+    );
+  });
+
   test.each([
     [
       "ResolutionError",
       new ResolutionError("Project 'x'", "not found", "sentry issue list"),
     ],
-    ["ValidationError", new ValidationError("bad")],
     ["SeerError", new SeerError("not_enabled")],
     ["ConfigError", new ConfigError("bad")],
     ["generic Error", new Error("boom")],