Add MCP protocol version 2025-11-25 - #1304
Open
DivyaMaddipudi wants to merge 2 commits into
Open
Conversation
franco2002lu
reviewed
Aug 5, 2026
| permits ProtocolVersion.UnknownVersion, ProtocolVersion.v2024_11_05, ProtocolVersion.v2025_03_26, | ||
| ProtocolVersion.v2025_06_18 { | ||
| ProtocolVersion.v2025_06_18, ProtocolVersion.v2025_11_25 { | ||
| public static final class v2025_11_25 extends ProtocolVersion { |
Contributor
There was a problem hiding this comment.
do you also intend to implement some of the new mcp features as well?
Contributor
Author
There was a problem hiding this comment.
For now we would like to support only the protocol version
franco2002lu
approved these changes
Aug 5, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What behavior changes?
Before: When a client sends
"protocolVersion": "2025-11-25"in the initialize request, the server treats it asUnknownVersionand omitsprotocolVersionfrom the response (falling back to the builder default"2024-11-05"). This breaks the handshake for clients expecting the server to echo back"2025-11-25".After: The server recognizes
"2025-11-25"as a known version and correctly echoes it back in the initialize response.Why is this change needed?
Clients like Claude Code and Cursor have adopted MCP spec version
2025-11-25and are sending it during initialization. The smithy-java MCP server only recognized versions up to2025-06-18, causing initialization failures for these clients. The2025-11-25spec uses the same handshake model (initialize → response → initialized) as prior versions, so no protocol-level changes are required beyond accepting the version string.How was this validated?
ProtocolVersionTest: validates version resolution, null handling, ordering, and unknown-version behaviorMcpServerTest.initializeWithV2025_11_25ProtocolVersion: end-to-end test confirming the server echoes the version and serves tools/list after handshakeWhat should reviewers focus on?
ProtocolVersion.java: The only production change — addsv2025_11_25to the sealed class hierarchy and switch statement. Note thatdefaultVersion()intentionally remains atv2025_03_26until the new capabilities (tasks, richer elicitation) are implemented.Additional Links