Support Vercel AI Data Stream Protocol

.gitignore

@@ -10,7 +10,7 @@ env*/
 /TODO.md
 /postgres-data/
 .DS_Store
-examples/pydantic_ai_examples/.chat_app_messages.sqlite
+.chat_app_messages.sqlite
 .cache/
 .vscode/
 /question_graph_history.json

README.md

@@ -50,8 +50,8 @@ Designed to give your IDE or AI coding agent as much context as possible for aut
 5. **Powerful Evals**:
 Enables you to systematically test and [evaluate](https://ai.pydantic.dev/evals) the performance and accuracy of the agentic systems you build, and monitor the performance over time in Pydantic Logfire.
 
-6. **MCP, A2A, and AG-UI**:
-Integrates the [Model Context Protocol](https://ai.pydantic.dev/mcp/client), [Agent2Agent](https://ai.pydantic.dev/a2a), and [AG-UI](https://ai.pydantic.dev/ag-ui) standards to give your agent access to external tools and data, let it interoperate with other agents, and build interactive applications with streaming event-based communication.
+6. **MCP, A2A, and UI**:
+Integrates the [Model Context Protocol](https://ai.pydantic.dev/mcp/overview), [Agent2Agent](https://ai.pydantic.dev/a2a), and various [UI event stream](https://ai.pydantic.dev/ui/overview) standards to give your agent access to external tools and data, let it interoperate with other agents, and build interactive applications with streaming event-based communication.
 
 7. **Human-in-the-Loop Tool Approval**:
 Easily lets you flag that certain tool calls [require approval](https://ai.pydantic.dev/deferred-tools#human-in-the-loop-tool-approval) before they can proceed, possibly depending on tool call arguments, conversation history, or user preferences.

docs-site/src/index.ts

@@ -55,6 +55,7 @@ const redirect_lookup: Record<string, string> = {
   '/examples': 'examples/setup/',
   '/mcp': '/mcp/overview/',
   '/models': '/models/overview/',
+  '/ag-ui': '/ui/ag-ui/'
 }
 
 function redirect(pathname: string): string | null {

docs/agents.md

@@ -103,6 +103,9 @@ async def main():
         FinalResultEvent(tool_name=None, tool_call_id=None),
         PartDeltaEvent(index=0, delta=TextPartDelta(content_delta='Mexico is Mexico ')),
         PartDeltaEvent(index=0, delta=TextPartDelta(content_delta='City.')),
+        PartEndEvent(
+            index=0, part=TextPart(content='The capital of Mexico is Mexico City.')
+        ),
         AgentRunResultEvent(
             result=AgentRunResult(output='The capital of Mexico is Mexico City.')
         ),

docs/api/ui/ag_ui.md

@@ -0,0 +1,5 @@
+# `pydantic_ai.ui.ag_ui`
+
+::: pydantic_ai.ui.ag_ui
+
+::: pydantic_ai.ui.ag_ui.app

docs/api/ui/base.md

@@ -0,0 +1,3 @@
+# `pydantic_ai.ui`
+
+::: pydantic_ai.ui

docs/api/ui/vercel_ai.md

@@ -0,0 +1,7 @@
+# `pydantic_ai.ui.vercel_ai`
+
+::: pydantic_ai.ui.vercel_ai
+
+::: pydantic_ai.ui.vercel_ai.request_types
+
+::: pydantic_ai.ui.vercel_ai.response_types

docs/examples/ag-ui.md

@@ -2,11 +2,11 @@
 
 Example of using Pydantic AI agents with the [AG-UI Dojo](https://github.com/ag-ui-protocol/ag-ui/tree/main/typescript-sdk/apps/dojo) example app.
 
-See the [AG-UI docs](../ag-ui.md) for more information about the AG-UI integration.
+See the [AG-UI docs](../ui/ag-ui.md) for more information about the AG-UI integration.
 
 Demonstrates:
 
-- [AG-UI](../ag-ui.md)
+- [AG-UI](../ui/ag-ui.md)
 - [Tools](../tools.md)
 
 ## Prerequisites

docs/index.md

@@ -25,8 +25,8 @@ Designed to give your IDE or AI coding agent as much context as possible for aut
 5. **Powerful Evals**:
 Enables you to systematically test and [evaluate](evals.md) the performance and accuracy of the agentic systems you build, and monitor the performance over time in Pydantic Logfire.
 
-6. **MCP, A2A, and AG-UI**:
-Integrates the [Model Context Protocol](mcp/client.md), [Agent2Agent](a2a.md), and [AG-UI](ag-ui.md) standards to give your agent access to external tools and data, let it interoperate with other agents, and build interactive applications with streaming event-based communication.
+6. **MCP, A2A, and UI**:
+Integrates the [Model Context Protocol](mcp/overview.md), [Agent2Agent](a2a.md), and various [UI event stream](ui/overview.md) standards to give your agent access to external tools and data, let it interoperate with other agents, and build interactive applications with streaming event-based communication.
 
 7. **Human-in-the-Loop Tool Approval**:
 Easily lets you flag that certain tool calls [require approval](deferred-tools.md#human-in-the-loop-tool-approval) before they can proceed, possibly depending on tool call arguments, conversation history, or user preferences.

docs/install.md

@@ -40,36 +40,35 @@ pip/uv-add "pydantic-ai-slim[openai]"
 
 `pydantic-ai-slim` has the following optional groups:
 
-* `logfire` — installs [`logfire`](logfire.md) [PyPI ↗](https://pypi.org/project/logfire){:target="_blank"}
-* `evals` — installs [`pydantic-evals`](evals.md) [PyPI ↗](https://pypi.org/project/pydantic-evals){:target="_blank"}
-* `openai` — installs `openai` [PyPI ↗](https://pypi.org/project/openai){:target="_blank"}
-* `vertexai` — installs `google-auth` [PyPI ↗](https://pypi.org/project/google-auth){:target="_blank"} and `requests` [PyPI ↗](https://pypi.org/project/requests){:target="_blank"}
-* `google` — installs `google-genai` [PyPI ↗](https://pypi.org/project/google-genai){:target="_blank"}
-* `anthropic` — installs `anthropic` [PyPI ↗](https://pypi.org/project/anthropic){:target="_blank"}
-* `groq` — installs `groq` [PyPI ↗](https://pypi.org/project/groq){:target="_blank"}
-* `mistral` — installs `mistralai` [PyPI ↗](https://pypi.org/project/mistralai){:target="_blank"}
-* `cohere` - installs `cohere` [PyPI ↗](https://pypi.org/project/cohere){:target="_blank"}
-* `bedrock` - installs `boto3` [PyPI ↗](https://pypi.org/project/boto3){:target="_blank"}
-* `huggingface` - installs `huggingface-hub[inference]` [PyPI ↗](https://pypi.org/project/huggingface-hub){:target="_blank"}
-* `outlines-transformers` - installs `outlines[transformers]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
-* `outlines-llamacpp` - installs `outlines[llamacpp]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
-* `outlines-mlxlm` - installs `outlines[mlxlm]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
-* `outlines-sglang` - installs `outlines[sglang]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
-* `outlines-vllm-offline` - installs `outlines[vllm-offline]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
-* `duckduckgo` - installs `ddgs` [PyPI ↗](https://pypi.org/project/ddgs){:target="_blank"}
-* `tavily` - installs `tavily-python` [PyPI ↗](https://pypi.org/project/tavily-python){:target="_blank"}
-* `cli` - installs `rich` [PyPI ↗](https://pypi.org/project/rich){:target="_blank"}, `prompt-toolkit` [PyPI ↗](https://pypi.org/project/prompt-toolkit){:target="_blank"}, and `argcomplete` [PyPI ↗](https://pypi.org/project/argcomplete){:target="_blank"}
-* `mcp` - installs `mcp` [PyPI ↗](https://pypi.org/project/mcp){:target="_blank"}
-* `fastmcp` - installs `fastmcp` [PyPI ↗](https://pypi.org/project/fastmcp){:target="_blank"}
-* `a2a` - installs `fasta2a` [PyPI ↗](https://pypi.org/project/fasta2a){:target="_blank"}
-* `ag-ui` - installs `ag-ui-protocol` [PyPI ↗](https://pypi.org/project/ag-ui-protocol){:target="_blank"} and `starlette` [PyPI ↗](https://pypi.org/project/starlette){:target="_blank"}
-* `dbos` - installs [`dbos`](durable_execution/dbos.md) [PyPI ↗](https://pypi.org/project/dbos){:target="_blank"}
-* `prefect` - installs [`prefect`](durable_execution/prefect.md) [PyPI ↗](https://pypi.org/project/prefect){:target="_blank"}
-
-See the [models](models/overview.md) documentation for information on which optional dependencies are required for each model.
+* `logfire` — installs [Pydantic Logfire](logfire.md) dependency `logfire` [PyPI ↗](https://pypi.org/project/logfire){:target="_blank"}
+* `evals` — installs [Pydantic Evals](evals.md) dependency `pydantic-evals` [PyPI ↗](https://pypi.org/project/pydantic-evals){:target="_blank"}
+* `openai` — installs [OpenAI Model](models/openai.md) dependency `openai` [PyPI ↗](https://pypi.org/project/openai){:target="_blank"}
+* `vertexai` — installs `GoogleVertexProvider` dependencies `google-auth` [PyPI ↗](https://pypi.org/project/google-auth){:target="_blank"} and `requests` [PyPI ↗](https://pypi.org/project/requests){:target="_blank"}
+* `google` — installs [Google Model](models/google.md) dependency `google-genai` [PyPI ↗](https://pypi.org/project/google-genai){:target="_blank"}
+* `anthropic` — installs [Anthropic Model](models/anthropic.md) dependency `anthropic` [PyPI ↗](https://pypi.org/project/anthropic){:target="_blank"}
+* `groq` — installs [Groq Model](models/groq.md) dependency `groq` [PyPI ↗](https://pypi.org/project/groq){:target="_blank"}
+* `mistral` — installs [Mistral Model](models/mistral.md) dependency `mistralai` [PyPI ↗](https://pypi.org/project/mistralai){:target="_blank"}
+* `cohere` - installs [Cohere Model](models/cohere.md) dependency `cohere` [PyPI ↗](https://pypi.org/project/cohere){:target="_blank"}
+* `bedrock` - installs [Bedrock Model](models/bedrock.md) dependency `boto3` [PyPI ↗](https://pypi.org/project/boto3){:target="_blank"}
+* `huggingface` - installs [Hugging Face Model](models/huggingface.md) dependency `huggingface-hub[inference]` [PyPI ↗](https://pypi.org/project/huggingface-hub){:target="_blank"}
+* `outlines-transformers` - installs [Outlines Model](models/outlines.md) dependency `outlines[transformers]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
+* `outlines-llamacpp` - installs [Outlines Model](models/outlines.md) dependency `outlines[llamacpp]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
+* `outlines-mlxlm` - installs [Outlines Model](models/outlines.md) dependency `outlines[mlxlm]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
+* `outlines-sglang` - installs [Outlines Model](models/outlines.md) dependency `outlines[sglang]` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"}
+* `outlines-vllm-offline` - installs [Outlines Model](models/outlines.md) dependencies `outlines` [PyPI ↗](https://pypi.org/project/outlines){:target="_blank"} and `vllm` [PyPI ↗](https://pypi.org/project/vllm){:target="_blank"}
+* `duckduckgo` - installs [DuckDuckGo Search Tool](common-tools.md#duckduckgo-search-tool) dependency `ddgs` [PyPI ↗](https://pypi.org/project/ddgs){:target="_blank"}
+* `tavily` - installs [Tavily Search Tool](common-tools.md#tavily-search-tool) dependency `tavily-python` [PyPI ↗](https://pypi.org/project/tavily-python){:target="_blank"}
+* `cli` - installs [CLI](cli.md) dependencies `rich` [PyPI ↗](https://pypi.org/project/rich){:target="_blank"}, `prompt-toolkit` [PyPI ↗](https://pypi.org/project/prompt-toolkit){:target="_blank"}, and `argcomplete` [PyPI ↗](https://pypi.org/project/argcomplete){:target="_blank"}
+* `mcp` - installs [MCP](mcp/client.md) dependency `mcp` [PyPI ↗](https://pypi.org/project/mcp){:target="_blank"}
+* `fastmcp` - installs [FastMCP](mcp/fastmcp-client.md) dependency `fastmcp` [PyPI ↗](https://pypi.org/project/fastmcp){:target="_blank"}
+* `a2a` - installs [A2A](a2a.md) dependency `fasta2a` [PyPI ↗](https://pypi.org/project/fasta2a){:target="_blank"}
+* `ui` - installs [UI Event Streams](ui/overview.md) dependency `starlette` [PyPI ↗](https://pypi.org/project/starlette){:target="_blank"}
+* `ag-ui` - installs [AG-UI Event Stream Protocol](ui/ag-ui.md) dependencies `ag-ui-protocol` [PyPI ↗](https://pypi.org/project/ag-ui-protocol){:target="_blank"} and `starlette` [PyPI ↗](https://pypi.org/project/starlette){:target="_blank"}
+* `dbos` - installs [DBOS Durable Execution](durable_execution/dbos.md) dependency `dbos` [PyPI ↗](https://pypi.org/project/dbos){:target="_blank"}
+* `prefect` - installs [Prefect Durable Execution](durable_execution/prefect.md) dependency `prefect` [PyPI ↗](https://pypi.org/project/prefect){:target="_blank"}
 
 You can also install dependencies for multiple models and use cases, for example:
 
 ```bash
-pip/uv-add "pydantic-ai-slim[openai,vertexai,logfire]"
+pip/uv-add "pydantic-ai-slim[openai,google,logfire]"
 ```

docs/output.md

@@ -614,7 +614,6 @@ async def main():
             #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the '}
             #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the dog and the pyr'}
             #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the dog and the pyramid'}
-            #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the dog and the pyramid'}
 ```
 
 _(This example is complete, it can be run "as is" — you'll need to add `asyncio.run(main())` to run `main`)_
@@ -662,6 +661,7 @@ async def main():
             #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the dog and the pyr'}
             #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the dog and the pyramid'}
             #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the dog and the pyramid'}
+            #> {'name': 'Ben', 'dob': date(1990, 1, 28), 'bio': 'Likes the chain the dog and the pyramid'}
 ```
 
 1. [`stream_responses`][pydantic_ai.result.StreamedRunResult.stream_responses] streams the data as [`ModelResponse`][pydantic_ai.messages.ModelResponse] objects, thus iteration can't fail with a `ValidationError`.