Anthropic raised the maximum request size for the first-party Claude API's Messages API and Token Counting API from 32 MB to 128 MB on October 28, according to its developer-platform release notes. The change is live for developers on the first-party API.

The cap measures the raw bytes of the HTTP payload, not tokens, and it bit hardest on image-heavy requests: encoding images and PDFs for transport inflates their size by roughly a third, so developers could exhaust the old 32 MB ceiling — and hit hard 413 errors that stopped entire conversations — while still having plenty of context window left. Longer computer-use sessions are another beneficiary.

The increase does not change pricing or the context window itself. The other API surfaces keep their separate limits: 256 MB for the Message Batches API and 500 MB for the Files API.