{"version":"2.1.281","anchor":"uploaded-file-downloads-reuse-a-cache-and-join-in-flight-pre","canonical_anchor":"uploaded-file-downloads-reuse-a-cache-and-join-in-flight-pre","heading":"Uploaded file downloads reuse a cache and join in-flight prefetches","tier":null,"area":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.281\/e\/uploaded-file-downloads-reuse-a-cache-and-join-in-flight-pre","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.281","markdown":"### Uploaded file downloads reuse a cache and join in-flight prefetches\n\nAttached file downloads now reuse a checked local cache and can join a download of the same file that is already running\n\n**What**\n\nAttached files can be referenced by an id called `file_uuid`. When Claude Code fetches these files, it now keeps a cache per context and reuses a stored copy when possible. A stored copy is used only when both of these hold:\n\n- The sign-in token matches the one it was fetched with. The comparison uses a hash, a scrambled fingerprint of the token.\n\n- The file on disk still matches its SHA-256 checksum, a fingerprint of the file's contents.\n\nIf the same file is already being fetched ahead of time, the new request waits for that download instead of starting a second one. When the cache is full, the oldest entry is removed. New counters record how many files were reused, joined or prefetched.\n\n**Why**\n\nThe same attachment is downloaded fewer times. The two checks stop Claude Code from using a copy that has changed on disk or was fetched under a different sign-in."}