Shepherd
Runtime substrate that turns agent's execution into a Git-like trace
...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.