Haystack

Haystack is a Python framework for building retrieval-augmented pipelines and AI agents. Developers compose model generators, tools, document processing and other components inside their own applications. It is a framework rather than a ready-to-use assistant or a plugin for a coding-agent harness.

Version 3.4.0 adds an experimental ToolResultOffloadCompactor that can move older tool results out of an agent’s active context while preserving their contents in a store. Applications must provide a read-back tool using that same store if the agent should retrieve the full results later. The release requires Python 3.11 or newer and adds Python 3.15 support. The Apache 2.0 license covers the framework; model-provider access and any hosted inference charges remain separate.