Jev in practice: typed decisions, scoped authority

safe-upgrade is an open-source dependency-upgrade agent that separates judgment, control flow, and authority by combining Jev (typed probabilistic decisions), LangGraph (durable workflow state), and Tenuo (scoped runtime warrants). Repository evidence is transformed into a bounded set of eligible transitions by trusted code, Jev chooses among those options and returns a typed Choice with probabilities and confidence, and the runtime validates and routes that choice to a known worker; low confidence triggers deterministic fallbacks. This lets rich repository context be condensed into a small, machine-usable decision while preserving explicit uncertainty for routing and retries.

Once a decision maps to a worker, Tenuo issues short-lived, narrowed warrants that constrain tools, arguments, paths, and lifetime - for example, authoring tests gets read access plus test-write and run-check rights while implementers get separate write permissions but cannot alter tests. LangGraph records findings, attempts, and checkpoints so verification runs against the exact commit and working tree. In CI, a run-level warrant binds the run to a package, version, branch, and draft policy, providing two-tier control alongside job permissions. The architecture enforces closed decisions, scoped execution, separated duties, independent evidence, contained processes, and explicit uncertainty, and it generalizes to any workflow that computes valid transitions, asks Jev, validates the typed response, issues a narrow warrant, and verifies results.