fix(test): show the failed step on the single-run result card

src/commands/test.run.spec.ts

@@ -16,7 +16,7 @@ import { DRY_RUN_BANNER, resetDryRunBannerForTesting } from '../lib/client-facto
 import type { FetchImpl } from '../lib/http.js';
 import type { RunResponse, TriggerRunResponse, BatchRunFreshResponse } from '../lib/runs.types.js';
 import { takeTelemetryExtras } from '../lib/telemetry.js';
-import { runTestRun, runTestRunAll } from './test.js';
+import { renderRunResponseText, runTestRun, runTestRunAll } from './test.js';
 
 // ---------------------------------------------------------------------------
 // Helpers
@@ -7203,6 +7203,32 @@ describe('runTestRun — --target-url reachability preflight wiring', () => {
   });
 });
 
+describe('run card: failed step (#672)', () => {
+  it('prints failedStepIndex right after failureKind for a failed run', () => {
+    const lines = renderRunResponseText({ ...makeFailedRun(), failedStepIndex: 4 }).split('\n');
+    const kind = lines.indexOf('failureKind assertion');
+    expect(kind).toBeGreaterThanOrEqual(0);
+    expect(lines[kind + 1]).toBe('failedStepIndex 4');
+  });
+
+  it('prints it for a blocked run too', () => {
+    const text = renderRunResponseText({ ...makeFailedRun(), status: 'blocked' });
+    expect(text.split('\n')).toContain('failedStepIndex 2');
+  });
+
+  it('omits the line when the server reported no failed step', () => {
+    expect(renderRunResponseText({ ...makeFailedRun(), failedStepIndex: null })).not.toContain(
+      'failedStepIndex',
+    );
+  });
+
+  it('omits the line for a passed run', () => {
+    expect(renderRunResponseText({ ...makePassedRun(), failedStepIndex: 2 })).not.toContain(
+      'failedStepIndex',
+    );
+  });
+});
+
 describe('gh-output integration on single-test run --wait (Gap A)', () => {
   function singleRunHarness(run: RunResponse) {
     const { credentialsPath } = makeCreds();

src/commands/test.ts

@@ -7563,6 +7563,8 @@ export function renderRunResponseText(
   if (run.startedAt) lines.push(`startedAt   ${run.startedAt}`);
   if (run.finishedAt) lines.push(`finishedAt  ${run.finishedAt}`);
   if (run.failureKind) lines.push(`failureKind ${run.failureKind}`);
+  if ((run.status === 'failed' || run.status === 'blocked') && run.failedStepIndex !== null)
+    lines.push(`failedStepIndex ${run.failedStepIndex}`);
   // D5-UX: show the human error string when status is failed/blocked and
   // the backend provided it. Truncate long multi-line errors to the first
   // line (≤200 chars) so the text output stays readable. JSON mode is