The Anthropic API default — what 'no long-term retention' means
Anthropic's API processes the request, generates the response, and returns it. The input prompt and output response are not persisted to a long-term store for abuse monitoring, training improvement, analytics, or any other purpose. This is documented in Anthropic's published commercial terms and reinforced in the Anthropic Trust Center.
What this means operationally: when you send a Messages API request, Anthropic's inference infrastructure receives the request, the model processes it, the response is generated, and the response is returned to your client. No copy of the input or output is written to a persistent store for later access. The only persistent records are operational metadata (request count, token counts, latency) needed for billing and reliability.
What this does NOT mean: zero in-flight presence. During the inference call itself, the prompt is processed by the model in Anthropic's compute environment. This is unavoidable for any LLM inference service. The distinction is between in-flight presence (universal) and persistent storage past the call (avoided under no-long-term-retention).
What about caching: Anthropic's prompt caching feature stores cached prefixes encrypted for the configured TTL. This is the one exception to 'no persistence past the call' — cached content can outlive the call by up to the TTL. The cache is automatically evicted at TTL expiration. For most regulated buyers, the TTL-bounded cache is acceptable; some sovereign workloads disable caching for total no-persistence.