[faresobeid]

Store the engine's weight-version spans on the sampled assistant node. MessageNode.weight_versions holds vLLM's [{version, start, end}] spans over the node's sampled tokens (indexes into the completion). None when the engine labels none. TurnTokens.weight_versions carries them from generate() to the turn's commit, the same way sampling_mask is carried.

No-op on vLLM 0.31 and before PrimeIntellect-ai/renderers#195: with no weight_versions in the result, the node field stays None. It can land before prime-rl's vLLM 0.32 bump (PrimeIntellect-ai/prime-rl#4140). Needs renderers#195 to be populated; consumed by PrimeIntellect-ai/prime-rl#4141.

Test: pytest tests/unit/test_graph.py tests/unit/test_trace.py (35 passed).

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Note

Low Risk
Additive metadata plumbing with no behavior change when weight_versions is absent; limited to training trace construction.

Overview
Adds engine weight-version attribution for sampled assistant turns: vLLM can return {version, start, end} spans over completion tokens, and this PR threads them from generate() through the trace graph.

Introduces WeightVersionSpan and mirrors the existing sampling_mask pattern—a transient TurnTokens.weight_versions field populated in response_from_generate from result["weight_versions"], then copied onto MessageNode.weight_versions when the turn commits. Spans are completion-indexed (as vLLM returns them); the field stays None when the engine omits labels (e.g. vLLM ≤0.31 before renderers support).

^{Reviewed by Cursor Bugbot for commit 3f142cc. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Add engine weight-version spans to TurnTokens and assistant graph nodes

• Adds a WeightVersionSpan Pydantic model with an engine version string and inclusive-start/exclusive-end completion-token offsets in types.py
• TurnTokens gains an excluded weight_versions field, so spans travel from generation to turn commit but are dropped from serialized responses
• The generate response parser in train.py maps weight_versions entries into spans on TurnTokens
• _commit_turn in graph.py copies the span list onto the sampled assistant MessageNode, which now has an optional weight_versions field
• Behavioral Change: graph nodes serialize with a new optional weight_versions field; existing consumers that reject unknown fields may fail

^{Macroscope summarized 3f142cc.}