[nikolas-sapa]

Fixes #3720

Summary

• Ensures RFC 8707 resource parameter is preserved and forwarded to OAuthAuthorizationServerProvider.exchange_authorization_code and exchange_refresh_token.
• Adds backwards-compatible signature detection so existing custom providers without resource kwargs continue working without modification.
• Adds comprehensive unit tests for authorization code and refresh token exchanges with query and body resource indicators.

Motivation

Per RFC 8707 (Resource Indicators for OAuth 2.0), clients may specify a target resource parameter when exchanging authorization codes or refreshing tokens. Previously, TokenHandler did not pass resource down to exchange handlers, preventing authorization servers from issuing audience-scoped access tokens matching the target MCP server.

[github-actions]

This PR has been closed automatically. This repo only keeps pull requests open when they come from a maintainer, or from a contributor a maintainer has assigned to the linked issue, and you aren't currently assigned to #3720.

If a maintainer assigns you to #3720, this PR reopens on its own and there's nothing more you need to do here. Assignment is a maintainer call based on capacity; comments that only ask to be assigned don't factor in. What does help is engaging on the issue itself by confirming the repro, explaining why it matters for your use case, or describing the approach you'd take.

You're welcome to keep pushing commits here (just avoid force-pushing, since GitHub can't reopen a rewritten branch), but that on its own won't get the PR reviewed or the issue assigned, and realistically most auto-closed PRs stay closed. There's no need to open a new PR either way.

CONTRIBUTING.md has the full reasoning, but in short:

• We're a small team with very little capacity to review community PRs right now.
• Many recent PRs are AI-generated with little human review, and reviewing one carefully still costs a maintainer as much time as it ever did. A well-described issue is usually more useful to us than the code.

Maintainers: reopen, remove missing-issue-link, or add bypass-issue-check to override.