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Agent frameworks

Pydantic AI

Capture traces from Pydantic AI by pointing Logfire at Voxmith

Choose a setup method

Method Use it when
Voxmith skill You want your coding agent to inspect the app, make the change, and verify it.
Voxmith SDK You want explicit control over the interaction boundaries and fields.
OpenTelemetry The framework already emits useful spans or you operate an OTel pipeline.

Start with one method for a call path. Combining SDK tracking with framework OpenTelemetry on the same call can create duplicate interactions.

Recommended. Choose this path when you want your coding agent to inspect the project, select a supported transport, make the smallest instrumentation change, send a test event, and verify that it reached Voxmith.

Install the skill once in your coding-agent environment:

npx skills add Voxmith/skills --skill voxmith

Run the framework-specific prompt below from the application root. Review the resulting diff before deploying it.

Use the voxmith skill to add Voxmith analytics to this Pydantic AI application.
Org ID: your-org-id
Instrument the real agent.run_sync() or agent.run() path and verify one fresh interaction.

Manual setup: Voxmith SDK

pip install voxmith
import voxmith

voxmith.init("your-org-id")
interaction = voxmith.begin(user_id="u-42", agent_name="pydantic-support", input=prompt)
try:
    result = agent.run_sync(prompt)
    interaction.end(output=str(result.output))
except Exception as exc:
    interaction.end(output=str(exc), success=False)
    raise
finally:
    voxmith.shutdown()

Manual setup: OpenTelemetry

Pydantic AI uses Logfire for instrumentation. Point Logfire's OTLP exporter at Voxmith and disable its hosted backend.

Install

pip install pydantic-ai logfire

Setup

import os, logfire
from pydantic_ai import Agent
from opentelemetry import trace

os.environ["OTEL_EXPORTER_OTLP_ENDPOINT"] = "https://otel.voxmith.com"
os.environ["OTEL_EXPORTER_OTLP_HEADERS"] = "X-Voxmith-Org-ID=<your-org-id>"

logfire.configure(send_to_logfire=False)  # required: don't dual-send to Logfire
logfire.instrument_pydantic_ai()

agent = Agent("anthropic:claude-sonnet-4-5", system_prompt="...")

tracer = trace.get_tracer(__name__)
with tracer.start_as_current_span("chat-turn") as span:
    span.set_attribute("gen_ai.conversation.id", "sess-123")
    span.set_attribute("user.id", "u-42")
    agent.run_sync("Hello")

Spans use OTel GenAI semconv (gen_ai.input.messages, gen_ai.output.messages, gen_ai.tool.call.arguments, gen_ai.usage.*) plus pydantic_ai.all_messages. gen_ai.conversation.id is emitted natively when message history is provided to the agent.

Caveats

Do not set LOGFIRE_TOKEN: that re-enables the hosted backend.

Verify

Run one agent.run_sync call, then open Events in Voxmith. Confirm gen_ai.* and pydantic_ai.* attributes are present.

Troubleshooting

  • Keep send_to_logfire=False if you do not want dual-send to Logfire.
  • Do not set LOGFIRE_TOKEN unless you explicitly want hosted Logfire enabled.
  • Confirm OTEL_EXPORTER_OTLP_HEADERS contains X-Voxmith-Org-ID=<your-org-id>.

References

Next steps

  • Conversations: review the complete Pydantic AI interaction.
  • Events: inspect agent, model, and tool activity.
  • Intents: organize production conversations by what users wanted.