Errors and limits

Signal	ERP action
token 400 invalid_request	correct the form request to grant_type=client_credentials
token 401 invalid_client	stop; ask the operator to verify lifecycle; do not loop
resource 401	invalidate token, obtain another, and retry once
403 AUTHORIZATION_DENIED	stop and compare grant with discovery
404 RESOURCE_NOT_FOUND	do not guess alternatives; it may be anti-enumeration denial
409 FACILITY_IMPORT_IN_PROGRESS	poll the existing work, then retry the prepared request
409 IDEMPOTENCY_KEY_REUSED	incident: the same key has different content; do not paper over it
422 ACTIVITY_CAPABILITY_UNAVAILABLE	inspect capability/input and the declared probe context
429	honor Retry-After and bounded backoff
retryable 5xx/transport loss	outcome may be ambiguous; reuse the durable request/key

Define connect/read timeouts, maximum retries, polling interval/deadline, and maximum item pages. Never use an unbounded loop. If an error body cannot be decoded, retain only sanitized status and correlation data.

See the API reference for exact schemas and responses.