Unclear The size limits are not known, and it is not settled in which cases Claude Code does the unpacking itself.
What
MCP servers are outside tools you connect to Claude Code, and some of them talk to it over the web (HTTP). Claude Code now handles their responses with new rules:
- Responses compressed with gzip or deflate are unpacked by Claude Code itself.
- Responses compressed with br or zstd are refused, with a message saying the server sent a response compressed with br or zstd, that Claude Code reads only gzip and deflate, and that it did not read the response.
- Response bodies and streamed events have a size cap, counted after unpacking, and going over it ends in an error.
The plain HTTP connection and the connection used for claude.ai connectors now share the same tracking of whether a connection is alive.
Why
A server that replies in a compression format Claude Code can't read now fails with a clear explanation, and very large replies from an MCP server can no longer grow without limit.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The size limits are not known, and it is not settled in which cases Claude Code does the unpacking itself.