Roughly in the order features were added. Each works independently — the fastest way to try something is to open the Reproductions, Guide, or Spec pages.

Three execution layers

• Layer 1 — in-browser WebAssembly. Python (Pyodide) / Ruby.wasm / php-wasm / Rust (wasm32-wasip1). No account, no install — open the page and it runs.
• Layer 2 — Docker catalogue. Pinned Dockerfile + GHCR-published image. Visitor reproduces locally with one docker run.
• Layer 3 — record-replay. Self-contained GHCR images with the rr trace baked in. rr replay rewinds deterministically.

Reproduction catalogue

• 15 recipes shipped across the three layers, from browser-native WASM pages to Docker and record-replay snapshots.
• Faceted gallery, paste-an-error candidate matcher, project-level landing pages.

Public spec + CI integration

• Contract v1 — the verdict.json wire shape published as JSON Schema.
• Manifest v1 — TOML manifest letting an external repo declare a Vivarium-runnable reproduction with one .vivarium/manifest.toml file.
• Reusable verdict-capture GitHub Actions workflow, weekly cron drift detection, interactive manifest scaffolder.

AI agent integration

• Vivarium MCP server — 12 tools covering recipe discovery, verdict lookup, error-to-recipe matching, branch-fix verification, and authoring scaffolders (see the package README for the full surface).
• AI-slop verification flow — match the error → open a recipe → paste a candidate fix → re-run → compare verdicts side-by-side, end-to-end.

User interface

• Full EN ⇄ JA i18n with a symmetric URL tree and locale switcher.
• Persona-route guide (5 minutes / repo integration / AI agent / write a reproduction / verify a branch fix / run on a fork / glossary).
• Branch-fix verdict capture pipeline + side-by-side comparison page.

The forward-looking direction is being written up by the maintainer; details will land here at a separate moment.

For now this page captures "what's been built so far." If you have a use case or a "this is how I'd want to use it" request, drop it on GitHub Issues — those become the inputs when the forward map gets drawn up.