feat(models): add ChatGPT 5.3/5.4 aliases + OpenAI gpt-5.4-pro

[vincentkoc]

Relevant issues

Supersedes outdated PRs:

• feat: add gpt-5.3-codex model support #20550
• feat: add chatgpt 5.3-codex provider model (chatgpt/gpt-5.3-codex) #20552

Pre-Submission checklist

Please complete all items before asking a LiteLLM maintainer to review your PR

• I have Added testing in the tests/litellm/ directory, Adding at least 1 test is a hard requirement - see details
• My PR passes all unit tests on make test-unit
  • Targeted checks run in this environment:
    • uv run ruff check tests/test_litellm/llms/chatgpt/responses/test_chatgpt_responses_transformation.py (pass)
    • jq empty model_prices_and_context_window.json (pass)
    • jq empty litellm/model_prices_and_context_window_backup.json (pass)
  • Blocker for pytest in this environment:
    • ModuleNotFoundError: No module named 'litellm.llms.chatgpt'
    • ModuleNotFoundError: No module named 'litellm.llms.base_llm.evals'
• My PR's scope is as isolated as possible, it only solves 1 specific problem

CI (LiteLLM team)

• Branch creation CI run
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• Merge / cherry-pick CI run
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Type

🆕 New Feature
📖 Documentation
✅ Test

Changes

• Add ChatGPT OAuth model aliases for GPT-5.3 variants to both model maps:
  • chatgpt/gpt-5.3-codex
  • chatgpt/gpt-5.3-codex-spark
  • chatgpt/gpt-5.3-chat-latest
  • chatgpt/gpt-5.3-instant
• Update ChatGPT provider docs to use GPT-5.3 examples and list common GPT-5.3 model IDs.
• Extend ChatGPT responses transformation tests to verify provider config registration for 5.3 aliases and run core request/response assertions with 5.3 model names.

References

• https://developers.openai.com/api/docs/models/gpt-5.3-codex
• https://developers.openai.com/api/docs/models/gpt-5.3-chat-latest
• https://openai.com/index/introducing-gpt-5-3-codex-spark/
• https://openai.com/index/gpt-5-3-instant/

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Project	Deployment	Actions	Updated (UTC)
litellm	Ready	Preview, Comment	Mar 5, 2026 10:04pm

[greptile-apps]

Greptile Summary

This PR adds six new ChatGPT provider model aliases (chatgpt/gpt-5.4, chatgpt/gpt-5.4-pro, chatgpt/gpt-5.3-codex, chatgpt/gpt-5.3-codex-spark, chatgpt/gpt-5.3-instant, chatgpt/gpt-5.3-chat-latest) and two OpenAI provider entries (gpt-5.4-pro and gpt-5.4-pro-2026-03-05) to both model_prices_and_context_window.json files. Documentation is updated to reflect the new models in both ChatGPT and OpenAI provider guides, with complete proxy configuration examples. Test coverage is extended through parametrization of existing tests to verify provider configuration registration and parameter behavior for all new model variants.

The changes are consistent across JSON model registries, documentation, and test coverage. All new models are properly registered with appropriate endpoint support, token limits, and capability flags.

Confidence Score: 4/5

• Safe to merge - adds new model aliases with proper registration in model pricing files, consistent documentation, and parametrized test coverage.
• The PR successfully adds 6 new chatgpt/* model aliases (gpt-5.4, gpt-5.4-pro, gpt-5.3-codex, gpt-5.3-codex-spark, gpt-5.3-instant, gpt-5.3-chat-latest) and 2 OpenAI provider entries (gpt-5.4-pro variants) with complete JSON entries, updated documentation, and proper test coverage. All referenced models are properly registered in both model_prices_and_context_window.json files. The proxy configuration examples in chatgpt.md include all new aliases. Test coverage extends existing test suites with parametrization to verify provider configuration registration and parameter behavior for the new models.
• No files require special attention. All changes are consistent and complete.

_{Last reviewed commit: ba3ce77}

[vincentkoc]

Rebased on latest origin/main and addressed follow-up scope.

What I changed

• Added OpenAI API model map support for:
  • gpt-5.4-pro
  • gpt-5.4-pro-2026-03-05
• Added ChatGPT OAuth model aliases:
  • chatgpt/gpt-5.4
  • chatgpt/gpt-5.4-pro
• Updated docs:
  • OpenAI provider table now includes gpt-5.4* and gpt-5.4-pro*
  • ChatGPT provider examples now include gpt-5.4 / gpt-5.4-pro and keep 5.3 codex/spark/instant examples
• Extended tests:
  • ChatGPT responses config registration test includes chatgpt/gpt-5.4 + chatgpt/gpt-5.4-pro
  • GPT-5 transformation tests now assert gpt-5.4 detection and reasoning_effort="xhigh" behavior

Validation run

• jq empty model_prices_and_context_window.json
• jq empty litellm/model_prices_and_context_window_backup.json
• uv run ruff check tests/test_litellm/llms/chatgpt/responses/test_chatgpt_responses_transformation.py tests/test_litellm/llms/openai/test_gpt5_transformation.py

References

• https://openai.com/index/introducing-gpt-5-4/
• https://developers.openai.com/api/docs/models/gpt-5.4
• https://developers.openai.com/api/docs/models/gpt-5.4-pro

[vincentkoc]

@Sameerlite linking this as a follow-up to #22916. This PR covers the ChatGPT OAuth aliases and gpt-5.4-pro support that were not included there. Requesting your review.