feat(openai): (v1) support pdfs passed via url in standard format

[ccurme]

This requires a small refactor.

Currently we pass all standard inputs through convert_to_openai_data_block in langchain-core, which returns chat completions format. BaseChatOpenAI then translates to Responses format if needed.

PDFs specified via URLs are not supported by chat completions, so ideally convert_to_openai_data_block continues to raise an informative ValueError there.

Simplest solution IMO is to enable convert_to_openai_data_block to return either Chat Completions or Responses format, and do the translation there instead of in BaseChatOpenAI.

BaseChatOpenAI continues to accept chat completions format directly on Responses path.

[vercel]

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Project	Deployment	Preview	Comments	Updated (UTC)
langchain	Ready	Preview	Comment	Sep 10, 2025 2:12pm

[codspeed-hq]

CodSpeed WallTime Performance Report

Merging #32876 will degrade performances by 12.53%

_{Comparing cc/openai_pdf_url (9a9fc88) with wip-v1.0 (a48ace5)}

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

Summary

❌ 3 regressions
✅ 10 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	test_import_time[BaseChatModel]	494.9 ms	565.8 ms	-12.53%
❌	test_import_time[ChatPromptTemplate]	554.3 ms	628.8 ms	-11.84%
❌	test_import_time[PydanticOutputParser]	499.9 ms	561.3 ms	-10.94%

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #32876 will not alter performance

_{Comparing cc/openai_pdf_url (9a9fc88) with wip-v1.0 (a48ace5)}

Summary

✅ 14 untouched benchmarks

[ccurme]

Need to add back more descriptive warning / error if users pass {"type": "file", "url": "..."} to chat completions.