PDF page reads can be capped per message and per turn once the context has filled

What

The context is the amount of conversation Claude can hold at once. Once it has filled up one time, reading PDF pages can now be limited:

• CLAUDE_CODE_FILE_READ_MAX_PDF_PAGES_PER_MESSAGE sets how many pages each of Claude's messages may read. The caps only apply when this is set below the normal per-request page maximum.
• CLAUDE_CODE_FILE_READ_MAX_PDF_PAGES_PER_TURN sets the limit for a whole turn, with a built-in default if unset.
• A per-session record must also say the feature is enabled and enforced, with its threshold within bounds.
• A read over the limit is refused with a message starting 'The context has filled up once already', telling Claude to read fewer pages or answer from what it has and say which pages it did not reach.

Before, the only limit was the maximum page range per single request.

Why

After a long PDF has already filled the context once, Claude is pushed to answer with what it has rather than keep re-reading pages and filling the context again.