Shepherd

Shepherd is an early-stage Python runtime for building agents and meta-agents around reversible, inspectable execution traces. It records interactions and workspace changes as durable run histories instead of immediately applying an agent's output. Each result can be reviewed, executed separately, selected, merged, released, or discarded. Tasks are declared as Python functions whose signatures and documentation define the agent contract and required resources. Read-only and read-write repository grants are enforced through native operating-system sandboxing on supported macOS and Linux environments. Runs can be forked, replayed, reverted, and supervised, enabling counterfactual experiments, optimization, and training workflows. Shepherd also retains machine-readable records and supports offline deterministic examples, but its APIs may change while the project remains in alpha.