diff --git a/src/cli/telemetry/schemas/common-shapes.ts b/src/cli/telemetry/schemas/common-shapes.ts
index e3aa86bad..5a1c7e952 100644
--- a/src/cli/telemetry/schemas/common-shapes.ts
+++ b/src/cli/telemetry/schemas/common-shapes.ts
@@ -126,6 +126,7 @@ export const ErrorName = z.enum([
   'ServerError',
   'TimeoutError',
   'UnsupportedLanguageError',
+  'UserCancellationError',
   'ValidationError',
   'UnknownError',
 ]);
diff --git a/src/cli/tui/hooks/useCdkPreflight.ts b/src/cli/tui/hooks/useCdkPreflight.ts
index 4602c1c14..3ab7256ec 100644
--- a/src/cli/tui/hooks/useCdkPreflight.ts
+++ b/src/cli/tui/hooks/useCdkPreflight.ts
@@ -1,5 +1,5 @@
-import { ConfigIO, SecureCredentials } from '../../../lib';
-import { AwsCredentialsError } from '../../../lib/errors/types';
+import { ConfigIO, SecureCredentials, toError } from '../../../lib';
+import { AwsCredentialsError, UserCancellationError } from '../../../lib/errors/types';
 import type { DeployedState } from '../../../schema';
 import { applyTargetRegionToEnv } from '../../aws';
 import { validateAwsCredentials } from '../../aws/account';
@@ -66,6 +66,8 @@ export interface PreflightResult {
   hasTokenExpiredError: boolean;
   /** True if preflight failed due to missing AWS credentials (not configured) */
   hasCredentialsError: boolean;
+  /** The error that caused preflight to fail, if any */
+  lastError?: Error;
   /** Missing credentials that need to be provided */
   missingCredentials: MissingCredential[];
   /** KMS key ARN used for identity token vault encryption */
@@ -134,6 +136,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
     Record<string, { credentialProviderArn: string; clientSecretArn?: string; callbackUrl?: string }>
   >({});
   const [teardownConfirmed, setTeardownConfirmed] = useState(false);
+  const lastErrorRef = useRef<Error | undefined>(undefined);
 
   // Guard against concurrent runs (React StrictMode, re-renders, etc.)
   const isRunningRef = useRef(false);
@@ -157,6 +160,12 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
     setSteps(BASE_PREFLIGHT_STEPS.map(s => ({ ...s, status: 'pending' as const })));
   };
 
+  const failPreflight = (err: unknown) => {
+    lastErrorRef.current = toError(err);
+    setPhase('error');
+    isRunningRef.current = false;
+  };
+
   // Dispose wrapper and clear ref
   const disposeWrapper = useCallback(async () => {
     if (wrapperRef.current) {
@@ -231,8 +240,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
   }, []);
 
   const cancelTeardown = useCallback(() => {
-    setPhase('error');
-    isRunningRef.current = false;
+    failPreflight(new UserCancellationError());
     restoreRegionEnv();
   }, [restoreRegionEnv]);
 
@@ -269,6 +277,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
     if (phase !== 'running') return;
     if (isRunningRef.current) return;
     isRunningRef.current = true;
+    lastErrorRef.current = undefined;
 
     const handleUnhandledRejection = (reason: unknown) => {
       const error = formatError(reason);
@@ -287,8 +296,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
         }
         return prev;
       });
-      setPhase('error');
-      isRunningRef.current = false;
+      failPreflight(reason);
     };
 
     process.on('unhandledRejection', handleUnhandledRejection);
@@ -329,8 +337,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
             userMessage = getErrorMessage(err);
           }
           updateStep(STEP_VALIDATE, { status: 'error', error: userMessage });
-          setPhase('error');
-          isRunningRef.current = false;
+          failPreflight(err);
           return;
         }
 
@@ -354,8 +361,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
             const userMessage =
               isInteractive && err instanceof AwsCredentialsError ? err.shortMessage : getErrorMessage(err);
             updateStep(STEP_VALIDATE, { status: 'error', error: userMessage });
-            setPhase('error');
-            isRunningRef.current = false;
+            failPreflight(err);
             return;
           }
         }
@@ -369,8 +375,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
             const errorMsg = depsResult.errors.join('\n');
             logger.endStep('error', errorMsg);
             updateStep(STEP_DEPS, { status: 'error', error: errorMsg });
-            setPhase('error');
-            isRunningRef.current = false;
+            failPreflight(new Error(errorMsg));
             return;
           }
           // Log version info
@@ -386,8 +391,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
           const errorMsg = formatError(err);
           logger.endStep('error', errorMsg);
           updateStep(STEP_DEPS, { status: 'error', error: logger.getFailureMessage('Check dependencies') });
-          setPhase('error');
-          isRunningRef.current = false;
+          failPreflight(err);
           return;
         }
 
@@ -402,8 +406,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
           const errorMsg = formatError(err);
           logger.endStep('error', errorMsg);
           updateStep(STEP_BUILD, { status: 'error', error: logger.getFailureMessage('Build CDK project') });
-          setPhase('error');
-          isRunningRef.current = false;
+          failPreflight(err);
           return;
         }
 
@@ -450,8 +453,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
             status: 'error',
             error: logger.getFailureMessage('Synthesize CloudFormation'),
           });
-          setPhase('error');
-          isRunningRef.current = false;
+          failPreflight(err);
           return;
         }
 
@@ -466,8 +468,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               const errorMsg = stackStatus.message ?? `Stack ${stackStatus.blockingStack} is not in a deployable state`;
               logger.endStep('error', errorMsg);
               updateStepByLabel(LABEL_STACK_STATUS, { status: 'error', error: errorMsg });
-              setPhase('error');
-              isRunningRef.current = false;
+              failPreflight(new Error(errorMsg));
               return;
             }
             logger.endStep('success');
@@ -482,8 +483,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               status: 'error',
               error: logger.getFailureMessage('Check stack status'),
             });
-            setPhase('error');
-            isRunningRef.current = false;
+            failPreflight(err);
             return;
           }
         } else {
@@ -520,8 +520,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
           }
           return prev;
         });
-        setPhase('error');
-        isRunningRef.current = false;
+        failPreflight(err);
       }
     };
 
@@ -566,8 +565,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
             status: 'error',
             error: logger.getFailureMessage('Synthesize CloudFormation'),
           });
-          setPhase('error');
-          isRunningRef.current = false;
+          failPreflight(err);
           return;
         }
 
@@ -582,8 +580,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               const errorMsg = stackStatus.message ?? `Stack ${stackStatus.blockingStack} is not in a deployable state`;
               logger.endStep('error', errorMsg);
               updateStepByLabel(LABEL_STACK_STATUS, { status: 'error', error: errorMsg });
-              setPhase('error');
-              isRunningRef.current = false;
+              failPreflight(new Error(errorMsg));
               return;
             }
             logger.endStep('success');
@@ -598,8 +595,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               status: 'error',
               error: logger.getFailureMessage('Check stack status'),
             });
-            setPhase('error');
-            isRunningRef.current = false;
+            failPreflight(err);
             return;
           }
         } else {
@@ -647,8 +643,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
         } else if (hasOAuth) {
           updateStepByLabel(LABEL_OAUTH, { status: 'error', error: errorMsg });
         }
-        setPhase('error');
-        isRunningRef.current = false;
+        failPreflight(new Error(errorMsg));
         return;
       }
 
@@ -697,8 +692,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
           if (identityResult.hasErrors) {
             logger.endStep('error', 'Some API key providers failed to set up');
             updateStepByLabel(LABEL_API_KEY, { status: 'error', error: 'Some API key providers failed' });
-            setPhase('error');
-            isRunningRef.current = false;
+            failPreflight(new Error('Some API key providers failed to set up'));
             return;
           }
 
@@ -741,8 +735,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
           if (oauthResult.hasErrors) {
             logger.endStep('error', 'Some OAuth providers failed to set up');
             updateStepByLabel(LABEL_OAUTH, { status: 'error', error: 'Some OAuth providers failed' });
-            setPhase('error');
-            isRunningRef.current = false;
+            failPreflight(new Error('Some OAuth providers failed to set up'));
             return;
           }
 
@@ -807,8 +800,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
             status: 'error',
             error: logger.getFailureMessage('Synthesize CloudFormation'),
           });
-          setPhase('error');
-          isRunningRef.current = false;
+          failPreflight(err);
           return;
         }
 
@@ -822,8 +814,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               const errorMsg = stackStatus.message ?? `Stack ${stackStatus.blockingStack} is not in a deployable state`;
               logger.endStep('error', errorMsg);
               updateStepByLabel(LABEL_STACK_STATUS, { status: 'error', error: errorMsg });
-              setPhase('error');
-              isRunningRef.current = false;
+              failPreflight(new Error(errorMsg));
               return;
             }
             logger.endStep('success');
@@ -838,8 +829,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               status: 'error',
               error: logger.getFailureMessage('Check stack status'),
             });
-            setPhase('error');
-            isRunningRef.current = false;
+            failPreflight(err);
             return;
           }
         } else {
@@ -872,8 +862,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               : s
           )
         );
-        setPhase('error');
-        isRunningRef.current = false;
+        failPreflight(err);
       }
     };
 
@@ -908,8 +897,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
               : s
           )
         );
-        setPhase('error');
-        isRunningRef.current = false;
+        failPreflight(err);
       }
     };
 
@@ -925,6 +913,7 @@ export function useCdkPreflight(options: PreflightOptions): PreflightResult {
     switchableIoHost,
     hasTokenExpiredError,
     hasCredentialsError,
+    lastError: lastErrorRef.current,
     missingCredentials,
     identityKmsKeyArn,
     allCredentials,
diff --git a/src/cli/tui/screens/deploy/useDeployFlow.ts b/src/cli/tui/screens/deploy/useDeployFlow.ts
index 8b0295744..6a709438d 100644
--- a/src/cli/tui/screens/deploy/useDeployFlow.ts
+++ b/src/cli/tui/screens/deploy/useDeployFlow.ts
@@ -598,8 +598,20 @@ export function useDeployFlow(options: DeployFlowOptions = {}): DeployFlowState
   // Start deploy when preflight completes OR when shouldStartDeploy is set
   useEffect(() => {
     if (diffMode) return; // Diff mode uses its own effect
-    const shouldStart = skipPreflight ? shouldStartDeploy : preflight.phase === 'complete';
+    const preflightDone = preflight.phase === 'complete' || preflight.phase === 'error';
+    const shouldStart = skipPreflight ? shouldStartDeploy : preflightDone;
     if (!shouldStart) return;
+
+    // Preflight failed — emit telemetry and bail
+    if (preflight.phase === 'error') {
+      const error = preflight.lastError ?? new Error('Preflight failed');
+      const attrs = context ? computeDeployAttrs(context.projectSpec, 'deploy') : { ...DEFAULT_DEPLOY_ATTRS };
+      withCommandRunTelemetry('deploy', attrs, () => ({ success: false as const, error })).catch(() => {
+        /* telemetry is best-effort */
+      });
+      return;
+    }
+
     if (deployStep.status !== 'pending') return;
     if (!cdkToolkitWrapper) return;
 
@@ -772,6 +784,7 @@ export function useDeployFlow(options: DeployFlowOptions = {}): DeployFlowState
     };
 
     void withCommandRunTelemetry('deploy', attrs, run);
+    // eslint-disable-next-line react-hooks/exhaustive-deps -- preflight.lastError and context are read only on error path
   }, [
     preflight.phase,
     cdkToolkitWrapper,
@@ -791,8 +804,22 @@ export function useDeployFlow(options: DeployFlowOptions = {}): DeployFlowState
   // Start diff when preflight completes (diff mode only)
   useEffect(() => {
     if (!diffMode) return;
-    const shouldStart = skipPreflight ? shouldStartDeploy : preflight.phase === 'complete';
+    const preflightDone = preflight.phase === 'complete' || preflight.phase === 'error';
+    const shouldStart = skipPreflight ? shouldStartDeploy : preflightDone;
     if (!shouldStart) return;
+
+    // Preflight failed — emit telemetry and bail
+    if (preflight.phase === 'error') {
+      const error = preflight.lastError ?? new Error('Preflight failed');
+      const attrs = context
+        ? computeDeployAttrs(context.projectSpec, 'diff')
+        : { ...DEFAULT_DEPLOY_ATTRS, deploy_mode: 'diff' as const };
+      withCommandRunTelemetry('deploy', attrs, () => ({ success: false as const, error })).catch(() => {
+        /* telemetry is best-effort */
+      });
+      return;
+    }
+
     if (diffStep.status !== 'pending') return;
     if (!cdkToolkitWrapper) return;
 
@@ -845,6 +872,7 @@ export function useDeployFlow(options: DeployFlowOptions = {}): DeployFlowState
     };
 
     void withCommandRunTelemetry('deploy', attrs, run);
+    // eslint-disable-next-line react-hooks/exhaustive-deps -- preflight.lastError and context are read only on error path
   }, [
     diffMode,
     preflight.phase,
diff --git a/src/lib/errors/types.ts b/src/lib/errors/types.ts
index 16940a3d2..726312eba 100644
--- a/src/lib/errors/types.ts
+++ b/src/lib/errors/types.ts
@@ -290,3 +290,12 @@ export class PollExhaustedError extends BaseError {
     super(`Polling exhausted after ${maxAttempts} attempts`, { defaultSource: 'service', ...options });
   }
 }
+
+/**
+ * Error indicating user cancellation interuption
+ */
+export class UserCancellationError extends BaseError {
+  constructor(options?: BaseErrorOptions) {
+    super(`User cancelled`, { defaultSource: 'user', ...options });
+  }
+}