[faresobeid]

Pass vLLM's weight_versions choice field through generate(). vLLM >= 0.32 returns, per choice, [{version, start, end}] spans over completion-token indexes: which engine weights sampled each token. None when the engine labels none.

No-op on vLLM 0.31: the field is absent, so the value is None. It can land before prime-rl's vLLM 0.32 bump (PrimeIntellect-ai/prime-rl#4140). Consumers: PrimeIntellect-ai/verifiers#2894 (stores the spans on the assistant node), then PrimeIntellect-ai/prime-rl#4141 (engines label the policy step; per-token policy age).

Test: pytest tests/test_client.py (32 passed).

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Note

Low Risk
Additive response field pass-through with no parsing or behavior change when the engine omits the key.

Overview
generate() now surfaces vLLM’s per-choice weight_versions field on its return dict, copied from the engine response via choice.get("weight_versions").

Docs describe it as vLLM ≥ 0.32’s list of {version, start, end} spans over completion-token indexes (which weight snapshot produced each token), or None when the engine omits or labels none—so older vLLM stays a no-op.

^{Reviewed by Cursor Bugbot for commit 0526944. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Add weight_versions to generate async client result

The async generate client function in client.py now returns the selected response choice's vLLM weight_versions span value, or None when absent. The field's structure and None case are documented on the function.

^{Macroscope summarized 0526944.}

[macroscopeapp]

Approvability

Verdict: Approved at 0526944

Macroscope's review found this PR approvable — This is a narrowly scoped, backwards-compatible addition to the existing generate() response that passes through optional vLLM weight_versions metadata without changing requests or existing behavior. Older vLLM responses remain a no-op with None.

Notes:

• Macroscope's correctness review did not run, so approvability was decided on eligibility alone.

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