<!-- GENERATED FROM prd.json — DO NOT EDIT AS AN INDEPENDENT SOURCE. prd.json IS AUTHORITATIVE. -->
# DGR-033: Build a standalone fake C++ gRPC Shard worker

- **Status / triage:** specification only; `ready-for-agent`; `passes: false`
- **Execution mode:** `AFK`
- **Milestone:** `M1`
- **Dependencies:** `DGR-022`, `DGR-024`, `DGR-032`
- **Blocks (derived):** `DGR-036`, `DGR-040`
- **Labels:** `area:worker`, `area:grpc`, `type:vertical-slice`, `priority:p0`, `ready-for-agent`
- **Evidence class:** `fixture`
- **Hardware:** `none`
- **Model:** `fake`
- **Upstream:** `no`

## Objective / description

Fresh Ralph session: read `.scratch/distributed-gguf-runtime/RALPH-CONTEXT.md`, source issue `.scratch/distributed-gguf-runtime/issues/033-build-a-standalone-fake-c-grpc-shard-worker.md`, and evidence READMEs for dependencies (DGR-022, DGR-024, DGR-032) before changing code. Inspect live source/tests rather than trusting legacy pass states. Objective: Prove the standalone worker process, stream, lifecycle, and supervision shape before llama.cpp integration.

## Acceptance criteria

- [ ] A standalone C++ executable serves the complete lifecycle and stream RPC contract using the fake engine.
- [ ] Python integration tests cover startup, health, capability, fragmented prefill, decode, release, cancellation, and graceful shutdown.
- [ ] Bounded messages, deadlines, flow control, and independent session cancellation are enforced.
- [ ] The worker exposes neither llama.cpp RPC nor arbitrary graph execution.
- [ ] Applicable shared quality gates in `prd.json` pass, and the evidence handoff records exact commands/results, 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-033/README.md`. Until every criterion and applicable gate has real evidence, this story remains `passes: false`. Legacy evidence is provenance only, not completion credit.
