Haystack 2.31

Apply the Python 3 prompt first. These rules cover Haystack 2.31 pipelines, prompt templates, agents and tools, retrieval, converters, model providers, telemetry, and deployment, and were checked against 2.31.0.

Version scope and runtime

• Install haystack-ai from the application's lock file and run it on Python 3.10 through 3.14, the interpreter versions this release classifies; its package metadata requires Python 3.10 or newer without declaring an upper bound.
• Treat 2.31 as a maintenance line that receives only security patches and critical bug fixes until the end of October 2026, and schedule the 3.x migration before that date.
• Do not carry Haystack 3.x behavior into this deployment: 2.31 has no deserialization module allowlist, no unsafe deserialization switch, and still executes tool calls through ToolInvoker.
• Enforce application controls for pipeline loading, URL fetching, and document-borne prompt injection; Haystack's security policy assigns these input-validation and trust boundaries to the application.

Pipeline definitions and serialization

• Treat every pipeline YAML, JSON, or dict as executable source: when a component type is not already registered, Pipeline.from_dict(), Pipeline.loads(), and Pipeline.load() import its named module before requiring the class to appear in the component registry.
• Remember that 2.31 keeps no allowlist over the modules a definition may name, so importing one executes its top-level code even when the registry lookup afterwards fails.
• Apply the same controls to serialized tools, toolsets, snapshot