Claude Code MCP 500K: Tool Result Persistence Override Lifts MCP Response Limit from Default to 500,000 Characters

Apiyi·high signal

MCP servers can now annotate tool results with _meta['anthropic/maxResultSizeChars'] to pass through up to 500K characters, eliminating the previous truncation bottleneck for large database schemas, log outputs, and file reads. This is a per-result override, not a global setting, allowing MCP servers to selectively expand limits for results that need it while keeping defaults tight for everything else.