Create a case (retention_mode REQUIRED, no default) · 2 credits

Opens a case (a persistent or ephemeral RAG workspace). 🔴 retention_mode is ALWAYS chosen explicitly (400 MISSING_RETENTION_MODE if absent): a persistent default would persist without permission and an ephemeral default would silently purge evidence — the only safe absence is not creating the case. Single debit here (2 cr expediente_open); the insert is rolled back if the debit fails. Supports Idempotency-Key (per-user encrypted cache). pii_gatekeeper:"off" requires account consent (403 PII_OPTOUT_NOT_ENABLED). Scope: cases | mcp | *.