Sourced from github.com/modelcontextprotocol/go-sdk's releases.

v1.2.0

This release is equivalent to v1.2.0-pre.2. Thank you to those who tested the prerelease.

This release adds partial support for the 2025-11-25 version of the MCP spec and fixes some bugs in the streamable transports. It also includes some minor new APIs, changes to contributing flows, and small bugfixes.

Contributing changes

• CONTRIBUTING.md is updated to remove the ad-hoc antitrust policy (#651), and add a dependency update policy (#635).
• An example server (examples/server/conformance) is added for the new conformance tests at modelcontextprotocol/conformance. Test can be run with scripts/conformance.sh (#650).

Partial support for the 2025-11-25 spec

The following SEPs from the 2025-11-25 spec are now supported. Please see modelcontextprotocol/go-sdk#725 for the proposed API additions included to support these SEPs.

• SEP-973: icons and metadata (modelcontextprotocol/go-sdk#570)
• SEP-986: tool name validation (modelcontextprotocol/go-sdk#640)
• SEP-1024: elicitation defaults (modelcontextprotocol/go-sdk#644)
• SEP-1036: URL mode elicitation (modelcontextprotocol/go-sdk#646)
• SEP-1699: SSE polling (modelcontextprotocol/go-sdk#663)
• SEP-1330: elicitation enum improvements (modelcontextprotocol/go-sdk#676)

Other API additions

• Common error codes are now available through the sentinel jsonrpc.Error (#452)
• OAuth 2.0 Protected Resource Metadata support (#643)
• ClientCapabilities.RootsV2 and RootCapabilities are added to work around an API bug (#607)
• Capabilities fields are added to ServerOptions and ClientOptions, to simplify capability configuration (#706)

Streamable fixes

Several bug fixes are included for the streamable transports:

• mcp: relax SSE connection response handling in non-strict mode by @​zhxie in modelcontextprotocol/go-sdk#611
• Fix: Skip non-message SSE events in processStream by @​raphaelmansuy in modelcontextprotocol/go-sdk#637
• mcp: better handling for streamable context cancellation by @​findleyr in modelcontextprotocol/go-sdk#677
• mcp: don't break the streamable client connection for transient errors by @​findleyr in modelcontextprotocol/go-sdk#723

Other notable bugfixes

• fix: handle Windows CRLF in MCP client by @​isfzhang in modelcontextprotocol/go-sdk#665
• auth, mcp: add UserID to TokenInfo for session hijacking prevention by @​findleyr in modelcontextprotocol/go-sdk#695
• internal/docs: document UserID for session hijacking prevention by @​findleyr in modelcontextprotocol/go-sdk#697
• mcp: allow re-using connections in more cases by @​howardjohn in modelcontextprotocol/go-sdk#709
• oauthex: validate URL schemes in auth server metadata and DCR by @​findleyr in modelcontextprotocol/go-sdk#712
• mcp: debounce server change notifications by @​findleyr in modelcontextprotocol/go-sdk#717
• oauthex: fix content type check in getJSON by @​nikolavp in modelcontextprotocol/go-sdk#721

New Contributors

• @​zhxie made their first contribution in modelcontextprotocol/go-sdk#611
• @​SpringMT made their first contribution in modelcontextprotocol/go-sdk#614

... (truncated)

• 411d5a0 mcp: switch icon theme to named string type (#733)
• 76e6854 docs: add GitHub Pages redirect to latest release documentation (#702)
• 875d1d3 mcp: don't break the streamable client connection for transient errors (#723)
• e009bac oauthex: fix content type check in getJSON (#721)
• 3430e22 mcp: add Capabilities fields to ServerOptions and ClientOptions (#713)
• bae0929 mcp: address review comments on streamable cleanup (#716)
• b3399e6 mcp: use args struct for CloseSSEStream (#718)
• 1a964ae mcp: debounce server change notifications (#717)
• a5e369e mcp: fix broken client root capabilities (#698)
• 307e32c oauthex: validate URL schemes in auth server metadata and DCR
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