neuron-tai/.scratch/distributed-gguf-runtime/issues/024-implement-real-generated-grpc-protocol-harness.md

DGR-024: Implement real generated-gRPC protocol harness

• Status / triage: specification only; ready-for-agent; passes: false
• Execution mode: AFK
• Milestone: M1
• Dependencies: DGR-022, DGR-023
• Blocks (derived): DGR-033, DGR-042
• Labels: area:protocol, area:testing, type:vertical-slice, priority:p0, ready-for-agent
• Evidence class: model-free
• Hardware: none
• Model: none
• Upstream: no

Objective / description

Build a real generated-gRPC protocol harness around the versioned shard_runtime.proto contract. Use generated Python and C++ stubs over an actual localhost transport and real process lifecycle; exercise captured deterministic protocol vectors and serialized protobuf bytes before a real model worker exists. Do not implement an in-memory fake transport, synthetic model outputs, or a production-looking stub/demo service.

Acceptance criteria

• Start a real localhost gRPC server process using generated bindings and connect to it with a generated client; no in-memory fake channel or direct method-only seam.
• Exercise prefill fragments, decode frames, release, cancel, flow-control, deadlines, malformed input, checksum failure, duplicates, and stale epochs using serialized protocol messages and captured deterministic vectors.
• Prove direct and opaque-relay paths preserve identical protobuf bytes by recording and comparing actual wire frames at both boundaries.
• Use real process/socket lifecycle and fail closed on transport, schema, epoch, size, cache, and deadline violations; do not claim model or accelerator behavior that is not exercised.
• Applicable shared quality gates pass, and evidence records exact commands, raw outputs, generated artifact identities, wire-frame hashes, changed files, limitations, and dependency handoff.

Shared quality gates

• Targeted deterministic tests pass; Python changes also pass python -m compileall packages tests.
• git diff --check passes.
• Default tests are model-download-free, API-credit-free, and GPU-free.
• Evidence README records exact changed files, commands/results, limitations, and dependency handoff; no fabricated evidence or inherited completion credit.
• Native changes pass focused out-of-tree CMake build and CTest; patch changes verify clean apply/check/reverse against the exact llama.cpp pin.
• Runs are opt-in and record exact artifact/split hashes, runtime/upstream pin, backend/driver, hardware, network, commands, and raw metrics. Model artifacts use configured mounted-drive storage and never /home.
• Preserve existing Transformers behavior and backend-agnostic Tracker routing/load balancing/billing/relay semantics unless an explicit versioned contract says otherwise. One scoped story commit is expected during execution, but this specification-materialization change is not committed.

Evidence handoff

Write and verify .scratch/distributed-gguf-runtime/evidence/DGR-024/README.md. Until every criterion and applicable gate has real evidence, this story remains passes: false. Legacy evidence is provenance only, not completion credit.