neuron-tai/.scratch/distributed-gguf-runtime/issues/065-define-v4-mtp-ownership-and-distributed-state-contract.md

DGR-065: Define V4 MTP ownership and distributed state contract

• Status / triage: specification only; ready-for-agent; passes: false
• Execution mode: AFK
• Milestone: M4
• Dependencies: DGR-051, DGR-054, DGR-060
• Blocks (derived): DGR-066
• Labels: area:deepseek-v4, area:mtp, type:contract, priority:p1, ready-for-agent
• Evidence class: fixture
• Hardware: none
• 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/065-define-v4-mtp-ownership-and-distributed-state-contract.md, and evidence READMEs for dependencies (DGR-051, DGR-054, DGR-060) before changing code. Inspect live source/tests rather than trusting legacy pass states. Objective: Lock MTP tensor, execution, boundary, acceptance/rejection, and session-state ownership before implementation while keeping MTP disabled for alpha.

Acceptance criteria

• Derive exact MTP tensor and execution ownership from the pinned V4 target and upstream llama.cpp graph, distinguishing main-layer, tail, and MTP responsibilities.
• Define typed MTP inputs/outputs plus accepted-token, rejection, rollback/truncation, position, cache, and session/epoch lifecycle semantics.
• Specify which MTP state remains shard-local and which typed boundary values cross a seam; prohibit WAN migration of KV or V4 auxiliary caches.
• Keep every MTP recipe disabled and unroutable for alpha, with fail-closed capability negotiation and deterministic contract fixtures.
• 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-065/README.md. Until every criterion and applicable gate has real evidence, this story remains passes: false. Legacy evidence is provenance only, not completion credit.