hajer — the Python SDK

Your application's model calls, as traces the Hajer platform stores and shows: every request a trace, every model call a generation under it, every conversation a session you can read top to bottom. And hajer eval: the repository's promptfoo suites, run on a pinned engine in CI and reported to the platform against the workflows and obligations they cover.

This package does not run your application, does not sit in your provider path and decides nothing on your behalf. It records what the application already does and exports it over OpenTelemetry.

Documentation: docs.hajer.ai

Install

pip install "hajer[otel]"          # the SDK with the OpenTelemetry exporter: what a production app installs
pip install hajer                  # httpx + pydantic only: records locally, exports nothing (no OTel SDK)
pip install "hajer[evals]"         # `hajer eval`: run promptfoo suites on the pinned engine (Node >= 22.22 on PATH)

Python ≥ 3.11.

Configure

In the Hajer app, Settings → API keys → Create key shows all three as a .env block. Without a key and team id the SDK is inert: every call is still recorded locally, nothing opens a socket, nothing raises. Every other setting is in Configuration.

Quickstart

import hajer
from openai import OpenAI

hajer.instrument()                      # every provider client built from here on records its model calls
client = OpenAI()                       # (or: client = hajer.wrap(OpenAI()) where you build it)

@hajer.workflow("answer-support-question")      # the unit the platform shows a trace as
def handle_ticket(ticket):
    with hajer.session(ticket.conversation_id), hajer.user(ticket.customer_id):
        reply = client.chat.completions.create(
            model="gpt-5", messages=[{"role": "user", "content": ticket.question}]
        ).choices[0].message.content
    return reply

Each handle_ticket call is one trace: a workflow answer-support-question span with a chat gpt-5 generation under it, and session.id / user.id on both. openai, anthropic, langchain-openai, langchain-anthropic, litellm and google-genai are supported, sync and async, streamed and not. Run hajer doctor when nothing arrives.

Evals

hajer eval            # runs every suite hajer.yaml declares, on the pinned promptfoo
hajer eval --upload   # and reports each run to the platform

Documentation

• Telemetry: instrumenting clients, workflows, sessions, export, redaction, configuration, the command line and the API reference.
• Evals: hajer eval, hajer.yaml, test metadata, providers, uploading, CI and the engine.
• Changelog · Contributing

License

MIT.