preval 0.1.0a1

AI Agent Observability — trace, evaluate, and debug LLM and voice AI agents in production.

Preval Python SDK

AI Agent Observability for production LLM and voice agents.

Preval traces, evaluates, and debugs your AI agents in production. Drop the SDK into your code and get a full waterfall view of every call, every span, every token — with cost, latency, and quality scores per request.

Install

pip install preval

For framework integrations, install an extra:

pip install preval[openai]
pip install preval[langchain]
pip install preval[crewai]
pip install preval[livekit]
pip install preval[vapi]
pip install preval[deepgram]
pip install preval[opentelemetry]   # auto-instrument 20+ providers

Or install everything at once:

pip install preval[all]

Quickstart

import preval

p = preval.init(
    api_key="your-api-key",
    project="my-project",
)
p.init_opentelemetry()

# All OpenAI / Anthropic / LangChain calls are now auto-traced
from openai import OpenAI

client = OpenAI()
response = client.chat.completions.create(
    model="gpt-4.1",
    messages=[{"role": "user", "content": "Hello!"}],
)

That's it. Open your dashboard at https://preval.dev and you'll see the trace within seconds.

Manual tracing

If you want full control over span boundaries:

from preval import PrevalObserve

observe = PrevalObserve(api_key="your-api-key", project="my-project")

with observe.trace("call-123", modality="voice", agent_name="support-bot") as t:
    with t.span("transcribe", type="stt", provider="deepgram") as s:
        s.set_output("Hello, how can I help?", confidence=0.95)
    with t.span("generate", type="llm", provider="openai", model="gpt-4o") as s:
        s.set_output("I can help you with that.")
        s.set_tokens(input=120, output=45)

observe.shutdown()

Integrations

Framework	Install	Usage
OpenAI	pip install preval[openai]	p.instrument_openai()
OpenAI Assistants	pip install preval[openai-assistants]	p.wrap_openai_assistants(client)
LangChain	pip install preval[langchain]	handler = p.langchain_handler()
CrewAI	pip install preval[crewai]	from preval.integrations.crewai_wrapper import instrument_crew
LiveKit	pip install preval[livekit]	from preval.integrations.livekit import PrevalLiveKitPlugin
Vapi	pip install preval[vapi]	from preval.integrations.vapi import VapiWebhookHandler
Deepgram	pip install preval[deepgram]	p.instrument_deepgram()
OpenTelemetry	pip install preval[opentelemetry]	p.init_opentelemetry() (auto-instruments 20+ providers)

Links

• Dashboard: https://preval.dev
• Documentation: https://docs.preval.dev
• Issues: https://github.com/preval-dev/preval-python-sdk/issues
• Changelog: https://github.com/preval-dev/preval-python-sdk/blob/main/CHANGELOG.md

License

MIT — see the LICENSE file for details.