Constrain access and rehearse rollback

Separate runtime and operator roles for FastAPI RAG endpoint whose v2 index is dark-launched then exposed to 5%. Runtime may only perform the narrow actions that release captain flipping rag_index_v2 for cohort canary needs; operators get audited break-glass with TTL. Encode a negative probe that denies the privilege trick related to browser-exposed flag lets attackers force v2 (unreviewed) index.

Redact prompts/PII at collection. Secrets enter via a manager or workload identity — never source, fixtures, or exception strings. Incident FLAG-CLIENT-TRUST-4 should be impossible if these controls hold. Output allowlists and schema checks stay in force on error paths.

Rehearse the rollback or kill switch timed against a clock. Record actor, reason, prior revision/secret/flag, and verification query. Invariant reminder: flag writes require RBAC; client-supplied flag values never authorize access.

Abuse cases unique to this lab include the privilege path implied by browser-exposed flag lets attackers force v2 (unreviewed) index. Prove a read-only role cannot mutate. Break-glass tokens expire; leftover tokens fail the drill. Dependency pin/digest story matters when images or models move under you. Document how to rotate the credential that FastAPI RAG endpoint whose v2 index is dark-launched then exposed to 5% uses without a full outage window longer than your dual-run plan. Security evidence is part of ship, not an appendix nobody reads.

List network egress destinations and justify each. Ensure debug endpoints are off by default in the shipping config. Verify that error responses do not echo secrets or raw stack frames to clients. For multi-tenant paths, add a cross-tenant probe fixture. Time the rollback drill twice — once with the author, once with a peer. Store the drill transcript beside the threat notes for the incident id. In this chapter the product is FastAPI RAG endpoint whose v2 index is dark-launched then exposed to 5%, the human stakeholder is release captain flipping rag_index_v2 for cohort canary, and the incident id you design against is FLAG-CLIENT-TRUST-4. Re-state the oracle in your notes — 5% cohort sees index_v2 citations; kill switch returns everyone to v1 in < 60s — and keep the invariant visible: flag writes require RBAC; client-supplied flag values never authorize access. Track flag_exposure_pct and citation_delta_v2_vs_v1 as the scoreboard. Surface under change control: POST /v1/rag/answer. If you only have forty minutes, finish the fixture for browser-exposed flag lets attackers force v2 (unreviewed) index before polishing UI. Promotion language stays ternary: promote, hold, or roll back based on evidence, not hope.