feat: Support logprobs for vLLM models in OpenAI Frontend
#8538
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…probs-in-triton-openai' of https://github.com/triton-inference-server/server into spolisetty/tri-216-add-support-for-logprobs-and-top_logprobs-in-triton-openai
…and-top_logprobs-in-triton-openai
…probs-in-triton-openai' of https://github.com/triton-inference-server/server into spolisetty/tri-216-add-support-for-logprobs-and-top_logprobs-in-triton-openai
pskiran1
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logprobs for vLLM models in OpenAI APIlogprobs for vLLM models in OpenAI Frontend
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Pull request overview
This PR adds support for logprobs (log probabilities) functionality in the OpenAI-compatible frontend for vLLM models. The feature allows users to request detailed probability information for generated tokens, which is useful for understanding model confidence and exploring alternative completions.
Key changes:
- Added logprobs support for both chat completions and standard completions endpoints
- Implemented conversion from vLLM's logprobs format to OpenAI's format
- Added comprehensive test coverage for logprobs functionality including validation and streaming
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| python/openai/openai_frontend/engine/utils/triton.py | Added helper functions to parse and convert logprobs from vLLM responses to OpenAI format for both chat and completion endpoints |
| python/openai/openai_frontend/engine/triton_engine.py | Integrated logprobs support into request handling, validation, and response generation for both streaming and non-streaming modes |
| python/openai/tests/test_openai_client.py | Added async tests for logprobs functionality using the OpenAI client library, including validation tests |
| python/openai/tests/test_chat_completions.py | Added HTTP-level tests for chat completions with logprobs, including edge cases and validation |
| python/openai/tests/test_completions.py | Added HTTP-level tests for completions with logprobs, including edge cases and validation |
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whoisj
reviewed
Nov 24, 2025
yinggeh
reviewed
Nov 26, 2025
pskiran1
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What does the PR do?
This PR adds support for
logprobsfunctionality in the OpenAI-compatible frontend for vLLM models. The feature allows users to request detailed probability information for generated tokens, which is useful for understanding model confidence and exploring alternative completions.Key changes:
Background:
https://platform.openai.com/docs/api-reference/completions/create
https://platform.openai.com/docs/api-reference/chat/create
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