attempt to add durable object - not working

[jldec]

pnpm dev currently fails with

20:15:59 [WARN] [config] The adapter @astrojs/cloudflare has limited support for "sharp". Certain features may not work as expected.
20:15:59 [types] Generated 0ms
service core:user:__WRANGLER_EXTERNAL_DURABLE_OBJECTS_WORKER: Worker "core:user:__WRANGLER_EXTERNAL_DURABLE_OBJECTS_WORKER"'s binding "MyDurableObject" refers to a service "core:user:worker", but no such service is defined.
The Workers runtime failed to start. There is likely additional logging output above.
  Location:
    /Users/jldec/astro/astro-do/node_modules/.pnpm/[email protected]/node_modules/miniflare/dist/src/index.js:9985:13
  Stack trace:
    at #assembleAndUpdateConfig (/Users/jldec/astro/astro-do/node_modules/.pnpm/[email protected]/node_modules/miniflare/dist/src/index.js:9985:13)
    at async Mutex.runWith (/Users/jldec/astro/astro-do/node_modules/.pnpm/[email protected]/node_modules/miniflare/dist/src/index.js:3632:16)
    at async Miniflare2._getProxyClient (/Users/jldec/astro/astro-do/node_modules/.pnpm/[email protected]/node_modules/miniflare/dist/src/index.js:10166:5)
    at async getPlatformProxy (/Users/jldec/astro/astro-do/node_modules/.pnpm/[email protected]_@[email protected]/node_modules/wrangler/wrangler-dist/cli.js:180408:20)
    at async withTakingALongTimeMsg (file:///Users/jldec/astro/astro-do/node_modules/.pnpm/[email protected]_@[email protected][email protected][email protected][email protected][email protected]/node_modules/astro/dist/integrations/hooks.js:28:18)

pnpm build succeeds, but trying to run the build locally fails as well, with a different error:

Your worker has access to the following bindings:
- Durable Objects:
  - MY_DURABLE_OBJECT: MyDurableObject
[wrangler:inf] Ready on http://localhost:8787

✘ [ERROR] Your Worker depends on the following Durable Objects, which are not exported in your entrypoint file: MyDurableObject.

  You should export these objects from your entrypoint, dist/_worker.js/index.js.