[afourniernv]

Summary

Show only middleware phases that actually ran, under the inspected request. Propagate correlation context to remote middleware. Keep routine details in sampled spans and bounded notable outcomes in the existing primary security record, without exporting request or response content.

Stacked review 2/6. This draft targets NVIDIA#5214; its diff contains only this layer, not the whole stack. The HTTP core is reviewed upstream in NVIDIA#5214; this dependent draft is on the author fork because upstream base branches are not available.

Related Issue

Closes NVIDIA#5394.
Tracking: NVIDIA#5210 (remains open).

Changes

• The local layer adds middleware phase and RPC instrumentation and bounded outcomes. Its public Rust result structs gain fields; external struct-literal compatibility needs review. No middleware protobuf field is added.
• Request and response phases and remote RPCs retain correct parentage, timings and outcomes.
• Mutation, denial, fail-open and capacity exhaustion are distinguishable without logging payloads.

Testing

• Exact middleware layer: mise run pre-commit passed, including strict clippy; 1,636 network, 134 middleware and 68 OTel tests passed.
• Behavior tests added or retained for this layer; DCO-signed commit 4a416e6.
• Cumulative native Hermes/Relay live validation on source 0764c1c4c: 13 selected workflows, 1,552 spans and 433 OCSF records; protected synthetic APIs and authenticated GitHub. The agent executed actual tools; no span parents were rewritten. This is cumulative evidence, not isolated-layer E2E qualification.
• Cumulative mise run test rerun passed with four test threads. Initial unchanged VM cleanup and gateway fixture flakes passed isolated reruns and the final full run. Full mise run ci is not claimed.

Checklist

• Follows Conventional Commits.
• Commits are signed off (DCO).
• Relevant crate and observability documentation updated.
• Maintainer acceptance and upstream promotion, after the parent layer lands.

Tested upstream snapshot: 638974575 (merged NVIDIA#4789). Newer main has advanced; this draft does not claim validation against today's main. It is for incremental code review, not merge readiness. No Relay dependency or reverse workload-reporting endpoint is introduced.