fix(auth): reject private_key_jwt config when no signing key was bound

cmd/config/init_auth_method_test.go

@@ -57,6 +57,21 @@ func TestResolveRegisterAuthMethod(t *testing.T) {
 	}
 }
 
+// TestValidatePKJWTKeyBinding covers the guard that rejects a registration
+// resolving to private_key_jwt with no signing key bound (e.g. an existing
+// secret-based app was selected on the confirm page).
+func TestValidatePKJWTKeyBinding(t *testing.T) {
+	if err := validatePKJWTKeyBinding(core.AuthMethodPrivateKeyJWT, ""); err == nil {
+		t.Error("pkjwt with empty keyLabel: expected error")
+	}
+	if err := validatePKJWTKeyBinding(core.AuthMethodPrivateKeyJWT, "agent-key"); err != nil {
+		t.Errorf("pkjwt with keyLabel: expected nil, got %v", err)
+	}
+	if err := validatePKJWTKeyBinding(core.AuthMethodClientSecret, ""); err != nil {
+		t.Errorf("client_secret: expected nil, got %v", err)
+	}
+}
+
 // TestResolveFinalAuthMethod locks the authoritative-method logic. The 2nd case
 // is the real bug: we requested private_key_jwt but the server resolved to an
 // existing client_secret app — we must persist client_secret, not pkjwt.

cmd/config/init_interactive.go

@@ -350,6 +350,9 @@ func runCreateAppFlow(ctx context.Context, f *cmdutil.Factory, brandOverride cor
 	if finalMethod == core.AuthMethodPrivateKeyJWT {
 		keyToStore = keyLabel
 	}
+	if err := validatePKJWTKeyBinding(finalMethod, keyToStore); err != nil {
+		return nil, err
+	}
 	return &configInitResult{
 		Mode:       "create",
 		Brand:      finalBrand,
@@ -360,6 +363,21 @@ func runCreateAppFlow(ctx context.Context, f *cmdutil.Factory, brandOverride cor
 	}, nil
 }
 
+// validatePKJWTKeyBinding rejects a registration that resolved to
+// private_key_jwt without a signing key bound to it. keyLabel is non-empty only
+// when the local flow chose private_key_jwt and signed a TEE attestation; a
+// resolved method of private_key_jwt with no key handle would save an unusable
+// config (rejected later at config load, surfacing as "saved OK, fails on first
+// use"), so it is caught here at registration time instead.
+func validatePKJWTKeyBinding(finalMethod, keyLabel string) error {
+	if finalMethod == core.AuthMethodPrivateKeyJWT && keyLabel == "" {
+		return errs.NewConfigError(errs.SubtypeInvalidClient,
+			"registration resolved to private_key_jwt but no signing key was bound to this app (an existing secret-based app may have been selected)").
+			WithHint("re-register with: lark-cli config init --new --auth-method private_key_jwt")
+	}
+	return nil
+}
+
 // resolveFinalAuthMethod picks the authoritative method from the poll result,
 // preferring private_key_jwt, then client_secret. It falls back to the requested
 // method when the server returns nothing (older servers).