Rasputin

Runtime recorder

An optional add-on for SvelteKit that attaches recent function arguments, return values, and call history to an error — not just the stack trace. Errors still report if you skip tuning it.

How it works

While a request runs, Rasputin can watch the functions your code calls and keep a short record of what they received and returned. If that work throws, the record is attached to the error.

The Vite plugin wraps those functions at build time. That wrapping is instrumentation. Do not add rasputin-instrument, --preload, or --import.

What you need to set up

If you followed Installation, both pieces are already in place:

1. Instrument functions

The @rasputin-ai/sveltekit/vite plugin instruments client and SSR modules.

2. Scope an execution

rasputinServerHooks creates one execution per HTTP request. Recorded state is only kept inside that request and attached if it throws.

Where to go next

  1. Compatibility — confirm adapter-node and your SvelteKit version.
  2. Setup — optionally redact fields or exclude noisy sources.