Skip to content

Cassian Gate

Deterministic pre-production proof layer for network changes.

Get started Read the principles


What it is

Cassian Gate is an execution-backed validation gate for network changes. Engineers declare topology, tests, and scenarios; the gate runs them through a clean-state authoritative path and returns explicit PASS/FAIL outcomes backed by auditable artifacts. The posture is behavior-first, artifact-authoritative, CI-safe, and local-first.

Where the authority line sits

Cassian Gate is not a general-purpose lab platform, not a chaos engine, not a controller, not a heuristic validator, not an AI decision system, and not a feature-parity NOS platform. AI surfaces remain advisory only — never authoritative. Exploratory workflows do not count as deployment authority.

Who it's for

Cassian Gate is built for network engineers who need proof before production, platform engineers who want a CI-safe gate around network changes, and teams that need machine-consumable artifacts instead of "probably safe" judgment. v2 ships the deterministic gate engine, FRR-based validation, named routing and policy invariants, scenario-based failure choreography, replay, blast radius, preflight, two-run comparison, candidate-config workflows, state capture, PCAP capture, and Terraform / Ansible adapters.

Get started

  • Quickstart


    Shortest path to an authoritative first PASS verdict from this repo.

    Get started

  • Topology Schema


    Schema spec for topologies, invariants, scenarios, and state probes.

    Schema (v1.5)

  • CLI Reference


    Every cassian subcommand, its flags, and its exit codes.

    CLI Reference

  • Proof Kit


    Sample topologies showing authoritative PASS and authoritative FAIL.

    Proof Kit

  • CI Integration


    GitHub Actions and GitLab CI templates that gate merges on proof.

    CI Integration

  • Project principles


    What Cassian Gate decides, and what it does not.

    Project principles