Add docs on instrumenting PydanticAI (#912)

Co-authored-by: ChristopherGS <[email protected]>
Co-authored-by: Marcelo Trylesinski <[email protected]>

Author: 3 people

docs/images/integrations/pydantic-ai/pydanticai-instrumentation-screenshot.png

@@ -0,0 +1,75 @@
+---
+integration: logfire
+---
+
+## Introduction
+
+Logfire supports instrumenting [PydanticAI](https://ai.pydantic.dev/).
+
+```python hl_lines="5"
+import logfire
+from pydantic_ai import Agent, RunContext
+
+logfire.configure()
+Agent.instrument_all()
+```
+
+!!! note
+    You will need to provide your `LOGFIRE_TOKEN` and LLM-appropriate API key environment variables.
+
+With that you get:
+
+* A span around all LLM calls your agent makes which records duration and captures any exceptions that might occur
+* Human-readable display of the conversation with the agent
+* Details of the request/response, including the number of tokens used
+
+You can also instrument **specific** agents with this approach:
+
+```python hl_lines="15"
+import logfire
+from pydantic_ai import Agent, RunContext
+
+logfire.configure()
+
+
+roulette_agent = Agent(
+    'openai:gpt-4o',
+    deps_type=int,
+    result_type=bool,
+    system_prompt=(
+        'Use the `roulette_wheel` function to see if the '
+        'customer has won based on the number they provide.'
+    ),
+    instrument=True
+)
+
+
+@roulette_agent.tool
+async def roulette_wheel(ctx: RunContext[int], square: int) -> str:
+    """check if the square is a winner"""
+    return 'winner' if square == ctx.deps else 'loser'
+
+
+# Run the agent
+success_number = 18
+result = roulette_agent.run_sync('Put my money on square eighteen', deps=success_number)
+print(result.data)
+#> True
+
+result = roulette_agent.run_sync('I bet five is the winner', deps=success_number)
+print(result.data)
+#> False
+```
+
+The above example displays like this in Logfire:
+
+<figure markdown="span">
+  ![Logfire PydanticAI Instrumentation](../../images/integrations/pydantic-ai/pydanticai-instrumentation-screenshot.
+png)
+  <figcaption>PydanticAI instrumented and displayed in Logfire</figcaption>
+</figure>
+
+You can use PydanticAI with a [large variety of LLMs](https://ai.pydantic.dev/api/models/base/#pydantic_ai.models.KnownModelName), the example
+just happens to show `gpt-4o`.
+
+For more information, see the [PydanticAI docs on instrumenting](https://ai.pydantic.dev/#instrumentation-with-pydantic-logfire) with Logfire.

docs/integrations/llms/pydanticai.md

@@ -99,6 +99,7 @@ nav:
   - Integrations:
       - Integrations: integrations/index.md
       - LLMs:
+          - PydanticAI: integrations/llms/pydanticai.md
           - LLamaIndex: integrations/llms/llamaindex.md
           - OpenAI: integrations/llms/openai.md
           - Anthropic: integrations/llms/anthropic.md