Support Vercel AI Data Stream Protocol #2923
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This would be a wonderful addon, looking forward to see it soon in main. |
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@samuelcolvin can you add it to docs such that it would be integrated as chat service in existing Fullstack apps that uses pydantic-ai as Agent stack. |
samuelcolvin
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183amir
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Thanks a lot for this! I left some comments on the code and I will try to test this and get back.
pydantic_ai_slim/pydantic_ai/vercel_ai_elements/request_types.py
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# Conflicts: # examples/pydantic_ai_examples/chat_app.py # pydantic_ai_slim/pydantic_ai/agent/abstract.py # pydantic_ai_slim/pydantic_ai/run.py
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# Conflicts: # pyproject.toml # tests/models/test_deepseek.py # tests/models/test_huggingface.py # uv.lock
# Conflicts: # docs/ui/ag-ui.md # examples/pydantic_ai_examples/ag_ui/api/agentic_chat.py # examples/pydantic_ai_examples/ag_ui/api/tool_based_generative_ui.py
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Implements a classmethod to convert Pydantic AI messages to AG-UI format, providing the reverse operation of the existing load_messages() method. This addresses PR pydantic#3068 feedback to use the new AGUIAdapter pattern introduced in PR pydantic#2923 instead of a standalone function. Changes: - Add AGUIAdapter.dump_messages() classmethod in ui/ag_ui/_adapter.py - Create helper functions: _convert_request_part(), _convert_response_parts(), _get_builtin_tool_call_id() - Handle all message part types: UserPromptPart, SystemPromptPart, ToolReturnPart, RetryPromptPart, TextPart, ToolCallPart, BuiltinToolCallPart, BuiltinToolReturnPart, ThinkingPart - Use part.model_response_str() for tool return content - Use part.args_as_json_str() for tool call arguments - Use part.model_response() for retry prompt content - Combine ToolCallPart and BuiltinToolCallPart handling using BaseToolCallPart - Handle text flow interruption by builtin tools (add \n\n separator) - Skip ThinkingPart in message history conversion - Add comprehensive test coverage with 3 new tests 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
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To do:
clai weborAgent.to_web()?This adds support for Vercel AI Elements streams to Pydantic AI.
There's an example frontend in a separate repo github.com/pydantic/pydantic-ai-chat the plan is to either make that into a more complete template, or release a
pydantic-ai-chatpython library which contains a pre-built react frontend.@DouweM we should rename this to use the proper terminology of the "Vercel AI Data Stream Protocol"
Here's a demo of basic usage:
pydantic-ai-chat.mp4