Add opt-in response_detail=summary with step and change counts, compact state, warnings, and actionable errors or prompts. Return an ocs_read batch_result request for full cached details without resuming mutations.
Keep compact/full behavior and idempotent batch retries intact. Preserve active-step context and report unavailable cached results explicitly. Document cache scope and retention; update schemas and digest.
Validation: 47 MCP unit tests, live stdio smoke test, rustfmt, and diff checks passed.