{"question":"When may a cache use heuristic freshness?","state":"grounded","http_status":200,"index_version":"0fc1763d6701","answer":"A cache may assign a heuristic expiration time when an explicit expiration time is not specified in the response. [rfc9111#4.2.2] A cache must not use heuristics to determine freshness when an explicit expiration time is present in the stored response. [rfc9111#4.2.2] A cache can use heuristics only on responses without explicit freshness whose status codes are defined as heuristically cacheable or that have been marked as explicitly cacheable. [rfc9111#4.2.2] When s-maxage, max-age, and Expires do not provide an explicit expiration time, a heuristic freshness lifetime might be applicable. [rfc9111#4.2.1]","message":"","citations":["rfc9111#4.2.2","rfc9111#4.2.1"],"supported":[{"text":"A cache may assign a heuristic expiration time when an explicit expiration time is not specified in the response.","citation":"rfc9111#4.2.2","coverage":1.0},{"text":"A cache must not use heuristics to determine freshness when an explicit expiration time is present in the stored response.","citation":"rfc9111#4.2.2","coverage":1.0},{"text":"A cache can use heuristics only on responses without explicit freshness whose status codes are defined as heuristically cacheable or that have been marked as explicitly cacheable.","citation":"rfc9111#4.2.2","coverage":1.0},{"text":"When s-maxage, max-age, and Expires do not provide an explicit expiration time, a heuristic freshness lifetime might be applicable.","citation":"rfc9111#4.2.1","coverage":0.9167}],"withdrawn":[],"consulted":[{"section_id":"rfc9111#4.2.2","citation":"RFC 9111 Section 4.2.2: Calculating Heuristic Freshness","rank":1,"score":0.7272},{"section_id":"rfc9111#4.2","citation":"RFC 9111 Section 4.2: Freshness","rank":3,"score":0.656},{"section_id":"rfc9111#4.2.1","citation":"RFC 9111 Section 4.2.1: Calculating Freshness Lifetime","rank":5,"score":0.6157},{"section_id":"rfc9111#1","citation":"RFC 9111 Section 1: Introduction","rank":7,"score":0.5669},{"section_id":"rfc9111#4.3.5","citation":"RFC 9111 Section 4.3.5: Freshening Responses with HEAD","rank":8,"score":0.5655},{"section_id":"rfc9111#6","citation":"RFC 9111 Section 6: Relationship to Applications and Other Caches","rank":9,"score":0.5567}],"budget":{"deadline_ms":150.0,"elapsed_ms":1.462,"exceeded":false,"stages":{"retrieval":0.443,"drafting":0.005,"grounding":0.99}}}