Known Limitations

Known limitations

Classroom 50 has no server: state lives in GitHub, and work runs as you or as GitHub Actions in your organization. That design keeps your data in your organization, but it also rules some features out and makes others behave unexpectedly. This page lists those limits, each with the reason and the workaround where one exists.

Roster and enrollment

Students can't be looked up by email. GitHub's API provides no way to find an account from an email address, so an emailed invitation can't be matched to a student until they accept it. Classroom 50 records the address on the roster as a pending row and fills in the account at the next sync, from either tool. To have usernames from the start, collect them up front; a signup form works well. See Add students and What triggers a sync.

A retained address is the one you invited. When you invite by email, the address stored on the roster is what you typed, which is not necessarily the email on the student's GitHub account. Treat it as your contact address for that student rather than a verified account detail. To record a different address, edit the roster row or upload a roster CSV once they've joined.

Students can't join through a link alone. GitHub requires an organization owner to invite members, so there's no self-service join link. Adding a student to the roster sends the invitation; once they've accepted it, assignment accept links work with no further action from you.

There's no roster self-identification at accept time. GitHub Classroom lets a student claim "I am this roster entry" when accepting. That step requires a server to mediate identities, so Classroom 50 identifies students by their GitHub account instead. A roster row names an account, not a person waiting to be claimed.

Visibility and feedback

Students can't see scores inside the app. Grading results are published as a Release on each student's repository, and the browser can't read Release assets across origins (GitHub redirects them to storage that lacks CORS headers). Point students at their repository's Releases page or the feedback pull request; the student view's View grade link opens the right Release. In-app scores are on the wish list; see #567.

There are no notifications or webhooks. Nothing runs while no one is signed in, so Classroom 50 can't email you when a student accepts or a grading run fails. GitHub's own notifications still work (for example, watching activity on the classroom50 repository or on feedback pull requests).

State refreshes only when a page loads. With no server polling in the background, the app reads GitHub's current state when you open or reload a page, and scores update only when collection runs (nightly, or Sync now). If a view looks stale, reload it. See When state refreshes.

Templates and student repositories

Students can read private templates in your organization. Accept works by giving the classroom's team read access to the template, so a curious student can browse it, including its history. Never commit solutions (or their history) to a template: develop privately and copy or squash the clean state into the template repository you register.

Student repositories are not forks. Accept generates a copy of the template; there is no upstream link, so template updates can't be pushed or pulled into accepted repositories. .gitignore and .github/ are the exception, re-fetched on every submit. See Updating starter code after students accept.

Renaming a repository breaks tracking. Classroom 50 finds student work by the repository name (<classroom>-<assignment>-<username>). A renamed repository disappears from the submissions view. Tell students not to rename their repositories; if one already did, rename it back.

Students can re-enable paused workflows. Students have write access to their repositories, which includes the Actions tab, so Pause autograding (and any Actions policy) is housekeeping, not enforcement: a student can re-enable the workflow. Treat grading controls as cost management, and use Close submission when you need actual enforcement.

Group repositories have no names. A group repository is named after the founder (the first student to accept); there's no group-name concept and no pre-assigned teams. See How group assignments work.

Timing

Published changes take a moment to go live. Classroom data that students read (the assignment list an accept link resolves against) is published through GitHub Pages, and a deploy takes from about 20 seconds to a few minutes. Right after you create or change an assignment, an accept link can briefly fail or show stale data; wait a minute and retry.

Requested, but architecturally hard

• LTI / LMS grade passback needs a server-to-server integration, which the serverless design doesn't currently accommodate. Exports (score CSVs and scores.json) are the supported path into an LMS today.
• Live in-app scores for students are blocked by the cross-origin limit above (#567).
• Roster self-selection would need a server to arbitrate identity claims.

Classroom 50 is open source and actively developed; if one of these matters to your course, share your use case in Discussions.

Further reading

• How Classroom 50 Works for the design behind these limits.
• Troubleshooting for error messages with fixes.