<!-- GENERATED FROM prd.json — DO NOT EDIT AS AN INDEPENDENT SOURCE. prd.json IS AUTHORITATIVE. -->
# DGR-061: Certify existing routing with 10+ GGUF stage candidates

- **Status / triage:** specification only; `ready-for-agent`; `passes: false`
- **Execution mode:** `AFK`
- **Milestone:** `M4`
- **Dependencies:** `DGR-043`, `DGR-057`, `DGR-058`
- **Blocks (derived):** `DGR-062`, `DGR-063`
- **Labels:** `area:tracker`, `area:scale`, `type:simulation`, `priority:p1`, `ready-for-agent`
- **Evidence class:** `fixture`
- **Hardware:** `none`
- **Model:** `generic`
- **Upstream:** `no`

## Objective / description

Fresh Ralph session: read `.scratch/distributed-gguf-runtime/RALPH-CONTEXT.md`, source issue `.scratch/distributed-gguf-runtime/issues/061-certify-existing-routing-with-10-gguf-stage-candidates.md`, and evidence READMEs for dependencies (DGR-043, DGR-057, DGR-058) before changing code. Inspect live source/tests rather than trusting legacy pass states. Objective: Certify that existing backend-agnostic routing consumes GGUF compatibility and measured-cost inputs for a 10+ candidate scenario without algorithm or policy redesign.

## Acceptance criteria

- [ ] Generate deterministic pools with 10+ compatible GGUF stage candidates plus slower, overloaded, unhealthy, and incompatible alternatives.
- [ ] Run the existing routing implementation unchanged and verify complete coverage, compatibility, acyclicity, and use of measured inputs.
- [ ] Regression-test that no stage count, quant, fixed split, architecture, or backend sequence is encoded in production routing policy.
- [ ] Verify existing route recomputation reacts to measured load/failure while tracker, load-balancing, billing, relay, and provider semantics remain unchanged.
- [ ] 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-061/README.md`. Until every criterion and applicable gate has real evidence, this story remains `passes: false`. Legacy evidence is provenance only, not completion credit.
