Last reviewed
Correct answer: A. Up to twenty files, each up to 500MB
Explanation
The principle — knowing the ceilings in advance is what stops an upload failing mid-task.
Why the key is correct — a chat accepts up to twenty files at up to 500MB each. Related rules sit alongside them: PDFs are limited to a thousand pages, and files added to a project's knowledge base are capped at 30MB each.
Why the others are wrong — attachments are not one at a time, the cap is not purely a combined total, and it has nothing to do with the project allowance.
Remember this — twenty files per chat, 500MB each, and a smaller limit inside projects.
Sources — Anthropic's file upload documentation.
Sources
“Up to 20 files per chat.”
“500MB per file.”
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