https://developers.cloudflare.com/workers/configuration/multipart-upload-metadata/ - see here. You a
https://developers.cloudflare.com/workers/configuration/multipart-upload-metadata/
- see here. You are also missing the Workflow definition. Otherwise, this isn’t specific to Workflows
Cloudflare Docs
If you're using the Workers Script Upload API or Version Upload API directly, multipart/form-data uploads require you to specify a metadata part. This metadata defines the Worker's configuration in JSON format, analogue to the wrangler.toml file.

