Original fictional stage case. Self-review. About twenty minutes.

1. Frontend end byte 40, backend end byte 28. Explain why agreeing on a boundary matters before either peer accepts another request.
2. Claims issuer is other-lab and audience notes. Signature verification succeeds. The notes policy expects issuer lab. State the remaining failed condition.
3. Caller A requests note 7, owned by A. Apply the private-owner rule separately from schema shape.
4. A public debug setting reveals internal configuration. Find the matching 2025 category and its identifier.
5. Write four limits: the byte positions are symbolic; no signature was computed here; the resolver is a policy model; the category does not establish the absence of other weaknesses.

Rubric: reject the modeled framing disagreement; the issuer condition fails; the same-owner note may be returned; Security Misconfiguration A02:2025; retain all four evidence limits.
Core readiness uses server/client topics and the map. Advanced lessons remain part of full-stage completion, and later stages remain available.