neuron-tai/.scratch/distributed-gguf-runtime/issues/049-keep-v4-attention-and-auxiliary-state-shard-local.md

DGR-049: Keep V4 attention and auxiliary state shard-local

• Status / triage: specification only; ready-for-agent; passes: false
• Execution mode: AFK
• Milestone: M3
• Dependencies: DGR-046, DGR-047
• Blocks (derived): DGR-051
• Labels: area:deepseek-v4, area:attention, type:runtime, priority:p0, ready-for-agent
• Evidence class: real-model
• Hardware: optional
• 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/049-keep-v4-attention-and-auxiliary-state-shard-local.md, and evidence READMEs for dependencies (DGR-046, DGR-047) before changing code. Inspect live source/tests rather than trusting legacy pass states. Objective: Bind V4 CSA/HCA/SWA/indexer/compressor and KV state to the owning shard session/epoch rather than transferring caches over the WAN.

Acceptance criteria

• Map CSA, HCA, SWA, indexer, compressor, and KV ownership from the pinned upstream graph to each owned layer range.
• Key all such caches/state by route session and epoch with bounded lifecycle, memory accounting, stale-epoch rejection, release, and eviction.
• Prove cross-stage messages carry only the typed architecture boundary and cache expectations, never per-layer cache contents.
• On route change or state loss, use explicit cache miss and re-prefill/restart; do not migrate V4 caches across workers.
• 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-049/README.md. Until every criterion and applicable gate has real evidence, this story remains passes: false. Legacy evidence is provenance only, not completion credit.