<!-- GENERATED FROM prd.json — DO NOT EDIT AS AN INDEPENDENT SOURCE. prd.json IS AUTHORITATIVE. -->
# DGR-019: Lock alpha and beta performance contracts

- **Status / triage:** specification only; `ready-for-human`; `passes: false`
- **Execution mode:** `HITL`
- **Milestone:** `M0`
- **Dependencies:** `DGR-017`
- **Blocks (derived):** `DGR-020`, `DGR-044`, `DGR-054`
- **Labels:** `area:performance`, `type:contract`, `priority:p0`, `gate:hitl`, `ready-for-human`
- **Evidence class:** `release`
- **Hardware:** `required`
- **Model:** `generic+deepseek-v4`
- **Upstream:** `no`

## Objective / description

Fresh Ralph session: read `.scratch/distributed-gguf-runtime/RALPH-CONTEXT.md`, source issue `.scratch/distributed-gguf-runtime/issues/019-lock-alpha-and-beta-performance-contracts.md`, and evidence READMEs for dependencies (DGR-017) before changing code. Inspect live source/tests rather than trusting legacy pass states. Objective: Freeze useful speed, correctness, memory-fit, and stop/go thresholds before implementation results are visible.

## Acceptance criteria

- [ ] Define controlled safetensors, whole-model GGUF, dense distributed GGUF, and V4 Flash distributed lanes with fixed prompts, context/output lengths, sampling, concurrency, hardware, and metrics.
- [ ] Alpha requires correctness plus a human-approved useful-speed threshold; beta adds concurrency, long-context, failure, and sustained-throughput thresholds.
- [ ] Separate quantization/model-fit gains from runtime, transport, batching, and kernel gains.
- [ ] Treat quants and 2–4/10+ stage counts only as named certification scenarios; no product logic may hardcode them.
- [ ] Lock thresholds and stop conditions in versioned machine-readable data before benchmark result ingestion.
- [ ] 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-019/README.md`. Until every criterion and applicable gate has real evidence, this story remains `passes: false`. Legacy evidence is provenance only, not completion credit.
