Cascade — Blast-radius analysis for PRs

Cascade helps teams see merge risk before production. Most AI coding tools only see a snippet; Cascade is built around IBM Bob Shell running non‑interactively on the server, fed a strict CASCADE‑ARCHITECT prompt so the agent can reason with real repository context (diff + curated file snapshots) and return validated JSON describing changed symbols, downstream impacts, severity, and suggested regression tests. The product is a Next.js “blast radius observatory”: users can run preset scenarios from a bundled demo monorepo, paste any unified diff, or paste a public GitHub PR URL to fetch the PR patch plus head‑branch file contents for context. The UI streams status, trace, and partial structured output over Server‑Sent Events, then renders an impact table once the response passes a Zod schema—so demos stay honest and failures are explicit (for example when Bob isn’t installed in an environment). For the hackathon, Cascade demonstrates Bob as a practical dev partner: it automates a workflow engineers already dread—estimating blast radius on PRs—and makes the result reviewable, shareable, and demo‑safe. The same architecture can extend to private repos with a token, stricter context limits, or a dedicated host where Bob Shell is available end‑to‑end.