No way to re-request a review on a PR created from a fork when the user is an external contributor

[gimenete]

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I'm trying to re-request a review (user-facing docs here https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/requesting-a-pull-request-review ) using the API but I get permissions errors, but it's a functionality that's possible to do via the UI. It doesn't seem to be possible to do via API when the request is made on behalf of a user that's an external contributor that created a PR in the base repo.

Expected workflow:

• User creates a fork of a public repo.
• User creates a PR where the headRepository is the fork and the baseRepository is the original repo.
• Someone reviews the PR.
• Through the API the user re-requests the review.

I've tried with the GraphQL API and with the REST API.

• For the GraphQL API I'm trying to use the RequestReviews mutation, but I get the following error: <user> does not have the correct permissions to execute RequestReviews
• With the REST API I'm using this endpoint https://docs.github.com/en/rest/pulls/review-requests?apiVersion=2022-11-28#request-reviewers-for-a-pull-request and I get a 404 (even though the base repository is public).

After the user that created the pull request is invited as collaborator, the same calls to the GraphQL API or the REST API succeed. For that reason I think this is a bug in the implementation:

• The REST endpoint and the GraphQL mutation work when the user is a collaborator.
• They return a permission error when the user is not a collaborator.
• However the action is possible to do in the UI also when the user is not a collaborator but is the author of the PR.

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[AndyKorol]

I've submitted a related feature request that expands on this issue for all reviewers (including bot reviewers like Copilot):

👉 https://github.com/orgs/community/discussions/186152

The core problem is the same: the API can request initial reviews, but there's no way to re-request a review programmatically. This becomes critical for AI-agent workflows where bots need to iterate on PR feedback.

If you're affected by this limitation, please upvote #186152 to help prioritize API parity with the web UI!

[gimenete]

Thanks! Upvoted!