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Canonical AI event

Model Context Protocol Client 2.2.0 Deprecates Constructors Without Expected Issuer

The client library now throws an error when a provider's client information mismatches the authorization server.

28 Sept 20261 verified claims1 sources1 observations
What happened

The official source reports this update: @modelcontextprotocol/client@2.2.0. Minor Changes #2887 edd12e2 Thanks @maxisbey ! - Constructing ClientCredentialsProvider , PrivateKeyJwtProvider , StaticPrivateKeyJwtProvider or CrossAppAccessProvider without expectedIssuer is deprecated: the constructor logs one console.warn and that call signature is marked @deprecated . Behaviour is otherwise unchanged. Pass the issuer of the authorization server the credentials were registered with. fetchToken() throws AuthorizationServerMismatchError , before sending anything, when the provider's client information is bound to a different authorization server than the one it is called with.

Why it matters

This official update documents a development concerning @modelcontextprotocol/client@2.2.0. Its practical significance depends on the scope and evidence stated by the source.

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Read the official source update and verify its stated scope, evidence and timing before acting on it.

Connected knowledge

Entities affected by this event

Typescript Sdksubject
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Evidence trail

Sources behind the event

Model Context Protocol TypeScript SDK official releases@modelcontextprotocol/client@2.2.0
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