vercel/ai · error · Error

ACP lifecycle state was produced by harness ${JSON.stringify

Error message

ACP lifecycle state was produced by harness ${JSON.stringify(lifecycleHarnessId)}, but this harness is ${JSON.stringify(harnessId)}.

What it means

Error "ACP lifecycle state was produced by harness ${JSON.stringify(lifecycleHarnessId)}, but this harness is ${JSON.stringify(harnessId)}." thrown in vercel/ai.

Source

Thrown at packages/harness-acp/src/v1/acp-v1-lifecycle.ts:65

}

export function validateACPLifecycleCompatibility({
  harnessId,
  lifecycleHarnessId,
  implementationIdentity,
  authenticationProfile,
  lifecycleData,
  sandboxId,
}: {
  harnessId: string;
  lifecycleHarnessId: string;
  implementationIdentity: string;
  authenticationProfile: ACPAuthenticationProfileIdentity;
  lifecycleData: ACPLifecycleData;
  sandboxId: string | undefined;
}): void {
  if (lifecycleHarnessId !== harnessId) {
    throw new Error(
      `ACP lifecycle state was produced by harness ${JSON.stringify(
        lifecycleHarnessId,
      )}, but this harness is ${JSON.stringify(harnessId)}.`,
    );
  }
  if (lifecycleData.implementationIdentity !== implementationIdentity) {
    throw new Error(
      'ACP lifecycle state is incompatible with the configured implementation.',
    );
  }
  if (
    lifecycleData.authenticationProfile?.digest !== authenticationProfile.digest
  ) {
    throw new Error(
      'ACP lifecycle state is incompatible with the configured authentication profile.',
    );
  }
  const expectedSandboxId = lifecycleData.bridge?.sandboxId;

View on GitHub (pinned to 69428b1f8b)

When it happens

Trigger: Thrown at packages/harness-acp/src/v1/acp-v1-lifecycle.ts:65 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/ai@69428b1f8b (2026-08-30). Data as JSON: /api/errors/95d79d510cb7c2be. Report an issue: GitHub.