# 06 — Implement architecture-defined boundary input/output

Status: ready-for-agent

## Mandatory fresh-session context

- Read [RALPH-CONTEXT.md](../RALPH-CONTEXT.md) completely before changing code.
- This issue is `DGR-006` in [prd.json](../prd.json).
- Read the evidence README for every dependency listed below.
- Inspect current code and `git status`; historical text and previous agent claims are not evidence.

## Description

As a Shard, I need to consume and emit the correct transformer boundary state so that disjoint processes reproduce whole-model execution.

## Expected durable outputs

- Architecture boundary adapter
- Whole-model/two-range parity tests and results
- evidence/DGR-006/README.md

## Acceptance criteria

- [ ] Head accepts token IDs and owns token embedding.
- [ ] Middle/tail bypass token embedding and accept the named boundary bundle.
- [ ] Amend the decode fast path so `DecodeStep` carries a versioned `TensorBundle`, not one `NamedTensor`; retain a compact one-tensor encoding and fallback compatibility, regenerate Python/C++ schema code, and update protocol goldens.
- [ ] Define an explicit typed tail result for logits and/or sampled token output, with sampling parameters and chat-template/reasoning mode bound to exact request/recipe identity.
- [ ] Non-tail emits the unnormalized architecture-defined residual/boundary before final norm/head and before tail-only row pruning.
- [ ] Tail emits logits or token output through an explicit sampling contract.
- [ ] Dense-Llama whole-model versus two-range prefill and greedy-decode parity passes the documented tolerance.
- [ ] The adapter interface fails closed for uncertified architectures.
- [ ] Targeted pytest tests pass
- [ ] python -m compileall packages tests passes for Python changes
- [ ] git diff --check passes
- [ ] Default tests remain deterministic, model-download-free, API-credit-free, and GPU-free
- [ ] Full deterministic pytest -q passes, or the exact pre-existing unrelated failure is recorded with a clean-tree reproduction
- [ ] Pinned native C++ target builds and focused CTest/protocol tests pass where native code is touched
- [ ] llama.cpp patch stack applies cleanly to the exact pinned commit where patch code is touched
- [ ] Read .scratch/distributed-gguf-runtime/RALPH-CONTEXT.md and this story issue completely before changing code
- [ ] Read and verify every dependency evidence README before relying on dependency behavior
- [ ] Preserve all pre-existing working-tree changes and stage only files belonging to this story
- [ ] Write .scratch/distributed-gguf-runtime/evidence/DGR-006/README.md with files changed, exact commands and real results, limitations, compatibility notes, and dependent-story handoff
- [ ] Update only this story issue to Status: done after every acceptance criterion and quality gate passes

## Dependency handoff

- `DGR-002` must have `passes: true`; read `../evidence/DGR-002/README.md` and verify its referenced files/commands.
- `DGR-005` must have `passes: true`; read `../evidence/DGR-005/README.md` and verify its referenced files/commands.

## Finish contract

- Create the task evidence directory and durable handoff required above.
- Preserve real failures and blockers; never fabricate benchmark, model, test or hardware output.
- Change this issue to `Status: done` only after all criteria pass.
- Emit `<promise>COMPLETE</promise>` only after the evidence handoff exists.

## References

- [Ralph execution context](../RALPH-CONTEXT.md)
- [PRD](../PRD.md)
- [Implementation strategy](../implementation-strategy.md)
- [Current architecture](../architecture.md)
- [Architecture decision](../ADR-0020-distributed-gguf-runtime.md)
