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An explicit empty `resource=` parameter was hitting the
`len(resources) == 1` branch and calling `GrantAudience("")`, producing
`aud:[""]` instead of the intended default. The fix is to treat an empty
string the same as an absent parameter by adding `&& resources[0] != ""`
to the condition, so an explicit empty value falls through to the
defaulting `else if` branch. A test covering this case is also added.
The comment on the defaulting branch overstated the invariant by
attributing safety to config-validation-time enforcement. The actual
safety comes from the `len == 1` guard on the same line; the comment is
updated to reflect that.
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The `TokenHandler` only granted an audience claim when the client included the RFC 8707 `resource` parameter. Clients that omit this optional parameter received a token with an empty `aud`, which caused `VirtualMCPServer` to reject every token its own auth server issued: the incoming OIDC validator requires `audience` to be set and rejects tokens that do not carry a matching claim. When no `resource` parameter is present and `AllowedAudiences` contains exactly one entry, the handler now defaults to granting that audience. The intended audience is unambiguous in that case, and `AllowedAudiences` is always non-empty (enforced at config validation time). The defaulting is restricted to `authorization_code` grants; for `refresh_token` grants fosite carries the originally-granted audience forward through the stored session automatically, so re-granting would conflict with its matching strategy. Fixes #4794
An explicit empty `resource=` parameter was hitting the
`len(resources) == 1` branch and calling `GrantAudience("")`, producing
`aud:[""]` instead of the intended default. The fix is to treat an empty
string the same as an absent parameter by adding `&& resources[0] != ""`
to the condition, so an explicit empty value falls through to the
defaulting `else if` branch. A test covering this case is also added.
The comment on the defaulting branch overstated the invariant by
attributing safety to config-validation-time enforcement. The actual
safety comes from the `len == 1` guard on the same line; the comment is
updated to reflect that.
The three separate tests covering the `aud` claim behaviour of `TokenHandler` shared identical structure. Merge them into a single `TestTokenHandler_AudienceClaim` table-driven test with subtests for the explicit-resource, absent-resource, and explicit-empty-resource cases. Also upgrades the former `TestTokenHandler_ResourceParameter`, which only asserted a 200 response, to verify the `aud` claim in the issued JWT.
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Test failures are unrelated with the change, I'll fix them anyway in a separate branch. |
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The fix in #4805 defaults the aud claim to the sole AllowedAudiences entry when clients omit the RFC 8707 resource parameter, but only included unit tests. Add an end-to-end integration test that verifies the full OAuth flow (authorize -> callback -> token exchange -> JWT validation) produces the correct audience when resource is omitted. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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…4818) The fix in #4805 defaults the aud claim to the sole AllowedAudiences entry when clients omit the RFC 8707 resource parameter, but only included unit tests. Add an end-to-end integration test that verifies the full OAuth flow (authorize -> callback -> token exchange -> JWT validation) produces the correct audience when resource is omitted. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
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The
TokenHandleronly granted an audience claim when the client included the RFC 8707resourceparameter. Clients that omit this optional parameter received a token with an emptyaud, which causedVirtualMCPServerto reject every token its own auth server issued: the incoming OIDC validator requiresaudienceto be set and rejects tokens that do not carry a matching claim.When no
resourceparameter is present andAllowedAudiencescontains exactly one entry, the handler now defaults to granting that audience. The intended audience is unambiguous in that case, andAllowedAudiencesis always non-empty (enforced at config validation time). The defaulting is restricted toauthorization_codegrants; forrefresh_tokengrants fosite carries the originally-granted audience forward through the stored session automatically, so re-granting would conflict with its matching strategy.Fixes #4794