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v1.5.0

This release is equivalent to v1.5.0-pre.1. Thank you to those who tested the pre-release.

In this release we introduce important enhancements to the client-side OAuth flows. We also introduce several smaller fixes and improvements.

Stabilization of client-side OAuth APIs

As previously communicated, we're stabilizing the client-side OAuth APIs in v1.5.0. This means that the mcp_go_client_oauth build tag will no longer be required to compile the functionality and standard backward compatibility guarantees apply from now on.

Compared to the experimental support published in v1.4.0, we made some backwards incompatible changes:

• auth.AuthorizationCodeHandlerConfig.AuthorizationCodeFetcher's type was changed from func(context.Context, *auth.AuthorizationArgs) (*auth.AuthorizationResult, error) to auth.AuthorizationCodeFetcher which is a reusable definition carrying the same underlying function type.
• auth.AuthorizationCodeHandlerConfig.PreregisteredClientConfig was removed and replaced with auth.AuthorizationCodeHandlerConfig.PreregisteredClient which uses a newly introduced oauthex.ClientCredentials type. The type used previously (auth.PreregisteredClientConfig) has been removed.
• Deprecated functionality has been removed from both auth and oauthex packages.

• all: stabilize client OAuth support by @​maciej-kisiel in modelcontextprotocol/go-sdk#861

Enterprise Managed Authorization support added

Support for Enterprise Managed Authorization has been added to auth/extauth package. Huge thanks to @​radar07 for the implementation!

• Enterprise managed authorization by @​radar07 in modelcontextprotocol/go-sdk#770

Note: this support is part of an official MCP extension and is not part of the core protocol. The support of this functionality is not covered by the principles defined in SDK tiers.

Other changes to the SDK

• examples: fix OAuth client example after latest changes. by @​maciej-kisiel in modelcontextprotocol/go-sdk#820
• build(deps): bump actions/upload-artifact from 4.6.1 to 7.0.0 by @​dependabot[bot] in modelcontextprotocol/go-sdk#824
• build(deps): bump ossf/scorecard-action from 2.4.1 to 2.4.3 by @​dependabot[bot] in modelcontextprotocol/go-sdk#825
• build(deps): bump actions/setup-go from 6.2.0 to 6.3.0 by @​dependabot[bot] in modelcontextprotocol/go-sdk#827
• build(deps): bump actions/checkout from 4.2.2 to 6.0.2 by @​dependabot[bot] in modelcontextprotocol/go-sdk#826
• mcp: simplify and unify unit tests introduced for sampling with tools. by @​maciej-kisiel in modelcontextprotocol/go-sdk#799
• auth: fix 2025-03-26 backcompat by @​maciej-kisiel in modelcontextprotocol/go-sdk#821
• chore: update deps after v1.4.0 release by @​maciej-kisiel in modelcontextprotocol/go-sdk#829
• build(deps): bump github/codeql-action from 3 to 4 by @​dependabot[bot] in modelcontextprotocol/go-sdk#823
• mcp: update latestProtocolVersion to 2025-11-25 by @​findleyr in modelcontextprotocol/go-sdk#724
• mcp: protect ioConn.protocolVersion with a mutex by @​maciej-kisiel in modelcontextprotocol/go-sdk#832
• examples: add an example that display header forwarding. by @​maciej-kisiel in modelcontextprotocol/go-sdk#836
• internal: fix Unicode zero character handling by @​maciej-kisiel in modelcontextprotocol/go-sdk#841
• auth: allow passing custom http.Client to AuthorizationCodeHandler by @​maciej-kisiel in modelcontextprotocol/go-sdk#840
• mcp: verify 'Origin' and 'Content-Type' headers by @​maciej-kisiel in modelcontextprotocol/go-sdk#842
• auth: return scope in WWW-Authenticate header. by @​maciej-kisiel in modelcontextprotocol/go-sdk#834
• mcp: fix setProgressToken when Meta is nil by @​StevenRChen in modelcontextprotocol/go-sdk#846
• all: clean up Go 1.24 specific code. by @​maciej-kisiel in modelcontextprotocol/go-sdk#850
• mcp: re-enable race test after fixing data races by @​maciej-kisiel in modelcontextprotocol/go-sdk#851
• mcp: handle empty chunks in MemoryEventStore by @​jba in modelcontextprotocol/go-sdk#862
• oauthex: use internal JSON library for decoding. by @​maciej-kisiel in modelcontextprotocol/go-sdk#866
• all: fix typos by @​alexandear in modelcontextprotocol/go-sdk#869
• mcp: return input validation errors as tool results, not JSON-RPC errors by @​ravyg in modelcontextprotocol/go-sdk#863
• all: modernize code by @​alexandear in modelcontextprotocol/go-sdk#868
• mcp: accept parameterized Accept media types by @​kalvinnchau in modelcontextprotocol/go-sdk#853

... (truncated)

• d3fd25b mcp: use http.ResponseController to ensure writes are flushed (#870)
• 638d404 all: stabilize client OAuth support (#861)
• c1a12cf mcp: accept parameterized Accept media types (#853)
• a1f808c all: modernize code (#868)
• 74d2751 mcp: return input validation errors as tool results, not JSON-RPC errors (#863)
• b71a839 all: fix typos (#869)
• 2d43865 Enterprise managed authorization (#770)
• 05277f6 oauthex: use internal JSON library for decoding. (#866)
• 150bca7 mcp: handle empty chunks in MemoryEventStore (#862)
• 755b9ed mcp: re-enable race test after fixing data races (#851)
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