## MODIFIED Requirements

### Requirement: Optional upstream payload tracing
When request-shape tracing for proxy routing is enabled, the system MUST log affinity decision metadata without exposing full prompt text or full cache keys. The trace MUST include request id, request kind, sticky kind, sticky-key source, whether a session header was present, whether a prompt-cache key was set/injected, and a stable tools hash when tools are present.

#### Scenario: Affinity request-shape tracing is enabled
- **WHEN** the proxy resolves routing for a Responses or compact request while request-shape tracing is enabled
- **THEN** the console shows the chosen sticky kind, sticky-key source, prompt-cache-key presence/injection state, and tools hash
- **AND** the console does not log raw prompt text or the full prompt-cache key unless the explicit raw-key flag is enabled
