v0.3.0

Features 🌟

• Added support for Server-Sent Events as a frontend transport option, unblocking server configurations that don't support the default transport (e.g. Amazon SageMaker) (#113)
• Configurable new-notebook template — Added c.MarimoProxyConfig.default_file, pointing at a template file whose contents seed every new notebook (via POST /marimo-tools/create-stub), so teams can ship shared imports/setup instead of the buil
  t-in boilerplate (#105)

Bug Fixes / Dependencies / Maintenance 🐛

• Fixed clipboard copy on non-secure-context deployments — navigator.clipboard is undefined outside HTTPS/localhost, breaking "Copy App Link"; swapped in Clipboard.copyToSystem from @jupyterlab/apputils (#111, reported by @NHanser)
• Fixed PEP 723 header drift introduced by the new-notebook template work (#110)
• Health checks now run client-side instead of proxying through the backend, so only the spawned marimo process is checked server-side (#104)
• Bumped @jupyterlab/builder to 4.5.8 and marimo to 0.23.9 to unblock CI (#106)
• Documented the Jupyter websocket message-size limitation for large cell outputs (#101)
• Dependency/CI maintenance — actions/checkout v7, codecov/codecov-action v7, digest pin updates (#107, #109, #112)

Contributors

• Thanks to @NHanser for reporting and fixing the clipboard bug in #111
• Thanks to @jtriggscw for contribution of templates in #105
• Thanks to @scttfrdmn and @eason9 for helping debug the issue in #8

Full Changelog: v0.2.3...v0.3.0