Epic 10: Operational tooling — MCP tools and observability

[mdproctor]

MCP tool: get_aml_investigation_status — active cases, specialist obligations, SLA health. MCP tool: get_sar_pipeline — SAR drafts in progress, compliance officer queue depth. MCP tool: get_investigation_audit — full causal chain for a specific case. MCP tool: list_stalled_investigators — agents with OPEN commitments past threshold. OTel spans correlated via LedgerTraceIdProvider. W3C PROV-DM export for FinCEN evidence chain.