[hickeyma]

Overview

Moves the parse and message assembly steps out of _derender_chat into a _parse_and_assemble helper. It's prep work for the inline derender output level in #56851 (Phase 2). It means that it can call this code instead of copying it.

Detais

• New OnlineDerenderer._parse_and_assemble() takes decoded text and returns the assistant ChatMessage. It covers building the parser, parsing, dropping reasoning when include_reasoning is off, tool call IDs and the empty content rule for named/required tool_choice.
• chat_template_kwargs is now resolved once per request instead of once per choice. The streaming parser path uses the same _resolve_chat_template_kwargs() helper, so that block isn't duplicated anymore.
• The decode call is pulled out of the parser/no-parser branches since both made the same call.
• No behavior change.

Validation

• pytest tests/entrypoints/scale_out/derender/test_derender.py -v
• `pytest tests/entrypoints/scale_out/derender/test_derender_stream.py -v
• pytest tests/entrypoints/scale_out/derender/test_derender_parity.py -v

There are no new tests. The existing derender unit and parity tests already cover this path and none of them needed changes.

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Pull Request Checklist

• I used vLLM's /pr-checklist skill. (Mandatory for agents, optional for humans).

• AI assistance was used during the creation of this PR.

• Design Fit: Minimizes impact on core components, reuses existing functionality, and justifies added complexity.

• Testing and Validation: Validates the change and ensures any added tests are meaningful and reliable, with CI coverage or documented CI resource constraints and validation performed outside CI.

• Code Quality and Style: Keeps code and comments clear and concise, and updates relevant documentation and examples.

• Pull Request Contents: Includes a brief summary and relevant links, supports claims with evidence, explains root causes and implementation trade-offs, and follows the contributing guide.

[claude]

Claude Code Review

This pull request is from a fork — automated review is disabled. A repository maintainer can comment @claude review to run a one-time review.

[sfeng33]

Thanks for the work, LGTM!

[sfeng33]

/ci run

[sfeng33]

/ci run --allow-stale

[github-actions]

✅ Triggered Buildkite CI #92952 for commit f2cdd21073d2.

⚠️ This PR is 1 commit behind upstream main. Running CI at your own risk because --allow-stale was requested; outdated CI configuration may cause failures. Before merging, merge or rebase onto the latest main, then rerun /ci run on the latest PR commit.

[vllm-agent]

CI selector (shadow): 2 test steps (5 jobs) instead of 35 (48 jobs)

Shadow mode: this changes nothing about what CI runs. It shows what the evidence-based selector would pick for this PR, next to today's rules. How it works.

Feedback welcome: reply here if it would skip a step this change needs, or runs something unrelated.

steps (jobs)	Today's rules	Selector	Would skip	Would add
NVIDIA, CPU and others	35 (48)	2 (5)	34 (44)	1 (1)
AMD mirrors	30 (38)	2 (5)	29 (34)	1 (1)

Selector would run (2)

• entrypoints-integration-api-server ×4
• scale-out-ec-e2e-2-gpus

Would skip (today's rules run them) (34)

• basic-correctness ×2
• basic-correctness-cpu-offload
• basic-correctness-cumem
• basic-correctness-prefetch-offload
• basic-correctness-sleep-mode
• basic-models-test-other-cpu
• basic-models-tests-initialization
• basic-models-tests-other
• benchmarks-cli-test
• cpu-language-generation-and-pooling-model-tests ×3
• cpu-multimodal-config
• cpu-params-env-tokenizers-parser
• cpu-reasoning-renderers
• cpu-tool-parsers
• entrypoints-integration-api-server-generate
• entrypoints-integration-api-server-openai-chat_completion
• entrypoints-integration-api-server-openai-completion
• entrypoints-integration-llm
• entrypoints-integration-multimodal
• entrypoints-integration-pooling
• entrypoints-integration-responses-api
• entrypoints-integration-speech_to_text
• kernels-fla-ops-test-b200
• kernels-mhc-test-b200
• kernels-root-misc-test-b200
• language-models-tests-granite-l4-compatibility
• language-models-tests-hybrid ×2
• language-models-tests-standard
• multi-modal-models-standard-1-qwen2
• multi-modal-models-standard-2-qwen3-gemma
• multi-modal-models-standard-3-llava-qwen2-vl
• multi-modal-models-standard-4-other-whisper
• multi-modal-processor ×4
• multi-modal-processor-cpu ×4

Would add (today's rules do not run them) (1)

• scale-out-ec-e2e-2-gpus (Python record)

AMD mirrors: would skip (29)

• basic-correctness ×2
• basic-correctness-cpu-offload
• basic-correctness-cumem
• basic-correctness-prefetch-offload
• basic-correctness-sleep-mode
• basic-models-tests-initialization
• basic-models-tests-other
• benchmarks-cli-test
• entrypoints-integration-api-server-generate
• entrypoints-integration-api-server-openai-chat_completion
• entrypoints-integration-api-server-openai-completion
• entrypoints-integration-llm
• entrypoints-integration-multimodal
• entrypoints-integration-pooling
• entrypoints-integration-responses-api
• entrypoints-integration-speech_to_text
• kernels-fla-ops-test-b200
• kernels-mhc-test-b200
• kernels-root-misc-test-b200
• language-models-tests-granite-l4-compatibility
• language-models-tests-hybrid ×2
• language-models-tests-standard
• multi-modal-models-standard-1-qwen2
• multi-modal-models-standard-2-qwen3-gemma
• multi-modal-models-standard-3-llava-qwen2-vl
• multi-modal-models-standard-4-other-whisper
• multi-modal-processor ×4
• platform-tests
• pytorch-compilation-passes-unit-tests

AMD mirrors: would add (1)

• scale-out-ec-e2e-2-gpus (Python record)

_{1 changed files · base 74c5cbcd7b · head f2cdd21073 · Python record: build 92838 at 92044241a0 · kernel record: table 9204424 (build 92838), map 9204424 · not counted: 10 build steps, 5 A100 steps the generator no longer emits, 0 optional steps the selector would also run}