quantizations

.scratch/qwen3.6-27b-demand-placement/PRD.md

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+# Qwen3.6-27B recommended deployment
+
+## Goal
+
+Offer the pinned `Qwen/Qwen3.6-27B` BF16 artifact as a recommended,
+text-only chat model. A valid chat request proves model demand. When the
+shared tracker pool has sufficient eligible capacity, the tracker deploys the
+model rather than waiting for an operator to request a load.
+
+## Catalog and artifacts
+
+- Canonical artifact: `Qwen/Qwen3.6-27B` at
+  `6a9e13bd6fc8f0983b9b99948120bc37f49c13e9`.
+- Tracker/peer artifact sources remain preferred over Hugging Face; this is a
+  system rule, not model-specific behavior.
+- BF16 is canonical. Nodes may load BF16, INT8, or NF4 from the canonical
+  shard according to their declared capability.
+- The model is text-only for this feature. Image inputs are rejected rather
+  than implicitly advertised as supported.
+
+## Quantization contract
+
+- Chat accepts an optional `quantization` field: `bfloat16`, `int8`, or
+  `nf4`. Omission means `bfloat16`.
+- A request is a minimum-quality constraint: BF16 uses BF16 only; INT8 can
+  use INT8 or BF16; NF4 can use NF4, INT8, or BF16.
+- A selectable variant requires complete end-to-end coverage using only
+  qualifying shards. Mixed qualifying precision is valid.
+- The UI defaults to the highest complete coverage, lists unavailable variants
+  as non-selectable, and gives them a small coverage-vote control.
+
+## Demand and placement
+
+- The first valid model request queues initial tracker-managed placement when
+  sufficient pooled capability exists. Until complete coverage exists, return
+  retryable `503 model_loading` with coverage metadata.
+- Demand and node supply are hive-wide; a leader makes each assignment and
+  broadcasts it to redundant trackers.
+- A request for an unavailable quantization is retained as demand. Votes are
+  weaker when another Qwen quantization is already usable.
+- If deployment replaces existing complete coverage, rolling demand for the
+  requested variant must exceed the displaced variant by more than 1.5x.
+  The multiplier and rolling window are tracker configuration.
+- Managed replacements require at least three complete copies beforehand and
+  must leave two. Managed placement has a configurable cooldown.
+
+## Node ownership
+
+- A startup-assigned `(model, shard range, quantization)` is pinned and never
+  changed by the tracker.
+- Spare capacity on a pinned node, and all capacity on a model-less node, is
+  available for tracker-managed assignments.
+- Tracker-added assignments are explicitly marked managed and may be moved or
+  removed by the tracker under the safety policy. Runtime UI controls are a
+  later feature.
+
+## Pricing
+
+Use exact-model online provider pricing. Preserve the last verified price if
+the provider lookup fails; use a model-specific development fallback only when
+there is no verified price.