diff --git a/sdk/typescript/src/worker-progress.ts b/sdk/typescript/src/worker-progress.ts
index 83fa1242..e83c240f 100644
--- a/sdk/typescript/src/worker-progress.ts
+++ b/sdk/typescript/src/worker-progress.ts
@@ -108,6 +108,7 @@ function preflightStatus(
   item: Readonly<Record<string, unknown>>,
 ): ScanWorkerStatus | null {
   if (
+    item["status"] === "failed" ||
     typeof item["command"] !== "string" ||
     !PREFLIGHT_COMMAND.test(item["command"]) ||
     typeof item["aggregated_output"] !== "string"
@@ -128,6 +129,23 @@ function preflightStatus(
   ) {
     return null;
   }
+  const exitCode = item["exit_code"];
+  if (typeof exitCode === "number") {
+    const expectedExitCode =
+      payload["status"] === "blocked"
+        ? 1
+        : payload["status"] === "incomplete"
+          ? 2
+          : payload["status"] === "ready"
+            ? 0
+            : null;
+    if (
+      (expectedExitCode !== null && exitCode !== expectedExitCode) ||
+      (expectedExitCode === null && exitCode !== 0)
+    ) {
+      return null;
+    }
+  }
   const results = payload["results"];
   const delegated = results.filter(
     (result): result is Record<string, unknown> =>
diff --git a/sdk/typescript/tests-ts/worker-preflight-failure.test.ts b/sdk/typescript/tests-ts/worker-preflight-failure.test.ts
new file mode 100644
index 00000000..6155132a
--- /dev/null
+++ b/sdk/typescript/tests-ts/worker-preflight-failure.test.ts
@@ -0,0 +1,58 @@
+import { expect, test } from "bun:test";
+import { workerStatusFromEvent } from "../src/worker-progress.js";
+
+function output(status: "ready" | "blocked" | "incomplete" = "ready") {
+  return JSON.stringify({
+    profile: "security_scan",
+    status,
+    results: [
+      { capability: "delegated_workers", status: "pass", actual: true },
+      { capability: "usable_worker_slots_6", status: "pass", actual: 8 },
+    ],
+  });
+}
+
+function event(overrides: Record<string, unknown> = {}) {
+  return {
+    type: "item.completed",
+    item: {
+      id: "preflight-1",
+      type: "command_execution",
+      command: "python3 /plugin/scripts/config_preflight.py --profile security_scan",
+      aggregated_output: output(),
+      status: "completed",
+      exit_code: 0,
+      ...overrides,
+    },
+  };
+}
+
+const capability = {
+  kind: "preflight",
+  delegation: "available",
+  configuredSlots: 8,
+} as const;
+
+test("ignores capability output from failed or contradictory preflight commands", () => {
+  expect(workerStatusFromEvent(event({ status: "failed" }))).toBeNull();
+  expect(workerStatusFromEvent(event({ exit_code: 2 }))).toBeNull();
+  expect(
+    workerStatusFromEvent(
+      event({ aggregated_output: output("blocked"), exit_code: 2 }),
+    ),
+  ).toBeNull();
+});
+
+test("keeps capability output from valid ready, blocked, and incomplete preflights", () => {
+  expect(workerStatusFromEvent(event())).toEqual(capability);
+  expect(
+    workerStatusFromEvent(
+      event({ aggregated_output: output("blocked"), exit_code: 1 }),
+    ),
+  ).toEqual(capability);
+  expect(
+    workerStatusFromEvent(
+      event({ aggregated_output: output("incomplete"), exit_code: 2 }),
+    ),
+  ).toEqual(capability);
+});