Installation

Arclasp ships as a Python package. The core SDK gives you the Chain API, backend client, payload sanitization, verification helpers, and exception types used by governed workflows. Production policy authority lives in the Arclasp backend.

Requirements

Python 3.10 or later
An Arclasp account
An Arclasp API key

Core SDK

pip install arclasp

Verify the install:

import arclasp

print(arclasp.__version__)

Framework extras

Install only the integration you need:

pip install "arclasp[langgraph]"
pip install "arclasp[langchain]"
pip install "arclasp[crewai]"
pip install "arclasp[mcp]"
pip install "arclasp[all]"

The package metadata is the source of truth for exact dependency ranges. For the current public beta, the intended compatibility constraints are:

Integration	Package constraint
LangGraph	`langgraph>=0.2.0,<0.4.0`
LangChain core	`langchain-core>=0.3.0,<0.4.0`
CrewAI	`crewai>=1.10.0,<2.0.0`
MCP Python SDK	`mcp>=1.0.0,<2.0.0`

The CrewAI optional dependency is installed only on Python versions below 3.14 because of its current dependency marker.

If your application uses additional framework packages, provider integrations, or model clients, install those separately. For example, a LangChain application that uses langchain-openai must install that provider package itself.

Get an API key

Create an API key from the Arclasp dashboard. Current keys retain the compatibility prefix prail_. Store the key in your own environment or secrets manager:

ARCLASP_API_KEY=prail_your_key_here

The SDK does not automatically read ARCLASP_API_KEY; your application reads it and passes the value to arclasp.init().

Initialize hosted Arclasp

import os
import arclasp

arclasp.init(
    api_key=os.environ["ARCLASP_API_KEY"],
)

Hosted Arclasp is the default backend. For local SDK/backend development, explicitly pass backend_url="http://localhost:8000".

Installing from source

For SDK development, install from a checkout:

pip install -e .

Normal users should install the released package from PyPI.

Get Started

Concepts

Framework Integration

Guides

Other

Installation

Installation

Requirements

Core SDK

Framework extras

Get an API key

Initialize hosted Arclasp

Installing from source

​Installation

​Requirements

​Core SDK

​Framework extras

​Get an API key

​Initialize hosted Arclasp

​Installing from source

Installation

Requirements

Core SDK

Framework extras

Get an API key

Initialize hosted Arclasp

Installing from source