Anthropic Ships Compaction API Beta and MCP Elicitation Hooks for Mid-Task Structured Input

Anthropic Platform Docs·high signal

Anthropic launched the Compaction API in beta — server-side context summarization enabling effectively infinite conversations without hitting context limits, available on Opus 4.6. Simultaneously, MCP servers can now request structured input mid-task via an interactive dialog through new Elicitation and ElicitationResult hooks that intercept and override responses before they are sent back. Both changes directly target long-horizon agent reliability where context overflow and mid-task ambiguity are the primary failure modes.