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

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.