<!-- GENERATED FROM prd.json — DO NOT EDIT AS AN INDEPENDENT SOURCE. prd.json IS AUTHORITATIVE. -->
# DGR-066: Implement and benchmark V4 MTP

- **Status / triage:** specification only; `ready-for-agent`; `passes: false`
- **Execution mode:** `AFK`
- **Milestone:** `M4`
- **Dependencies:** `DGR-054`, `DGR-060`, `DGR-064`, `DGR-065`
- **Blocks (derived):** `DGR-067`, `DGR-070`
- **Labels:** `area:deepseek-v4`, `area:mtp`, `type:runtime`, `priority:p1`, `ready-for-agent`
- **Evidence class:** `real-hardware`
- **Hardware:** `required`
- **Model:** `deepseek-v4-flash`
- **Upstream:** `yes`

## Objective / description

Fresh Ralph session: read `.scratch/distributed-gguf-runtime/RALPH-CONTEXT.md`, source issue `.scratch/distributed-gguf-runtime/issues/066-implement-and-benchmark-v4-mtp.md`, and evidence READMEs for dependencies (DGR-054, DGR-060, DGR-064, DGR-065) before changing code. Inspect live source/tests rather than trusting legacy pass states. Objective: Implement the locked MTP contract around upstream llama.cpp before beta, without making MTP an alpha prerequisite.

## Acceptance criteria

- [ ] Implement the exact DGR-065 MTP ownership and typed state contract against the pinned upstream V4 graph while preserving shard-local caches.
- [ ] Pass whole-model versus ranged MTP correctness, accepted-token, rejection, rollback/truncation, and session-isolation tests.
- [ ] Benchmark MTP-off versus MTP-on quality, accepted-token rate, TTFT, decode speed, seam bytes, and memory on the locked lane.
- [ ] Distinguish implemented, certified, disabled, and unsupported MTP recipes in fail-closed capability advertisement.
- [ ] 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-066/README.md`. Until every criterion and applicable gate has real evidence, this story remains `passes: false`. Legacy evidence is provenance only, not completion credit.
