Skip to content

docs(core): note that the protocol version constants are legacy-era only #2585

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
katayama8000 wants to merge 1 commit into
base: main
Choose a base branch
from
+25 −0
Open

docs(core): note that the protocol version constants are legacy-era only #2585

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 25 additions & 0 deletions packages/core/src/constants.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,30 @@
/* Legacy-era protocol revisions. These three constants describe only the legacy
* protocol era — the 2025-11-25 family and earlier, negotiated via the `initialize`
* handshake. The modern era (2026-07-28 and later) has no `initialize` handshake and
* is versioned separately, so no modern revision ever appears here. */

/**
* The newest protocol revision negotiable via the legacy `initialize` handshake.
*
* This is **not** the newest revision this SDK implements, and it is not a usable
* signal for whether the installed version supports a given spec revision — modern-era
* (2026-07-28+) support is deliberately kept out of this constant so that a modern
* version string can never leak into a legacy handshake.
*/
export const LATEST_PROTOCOL_VERSION = '2025-11-25';

/**
* The revision assumed for a legacy-era HTTP request that carries no
* `MCP-Protocol-Version` header, per the 2025-06-18 spec's backwards-compatibility rule.
*/
export const DEFAULT_NEGOTIATED_PROTOCOL_VERSION = '2025-03-26';

/**
* Legacy-era revisions this SDK can negotiate via `initialize`, in preference order.
*
* Used to validate the `MCP-Protocol-Version` header on the legacy HTTP transport.
* Modern-era revisions are tracked separately and are never members of this list.
*/
export const SUPPORTED_PROTOCOL_VERSIONS = [LATEST_PROTOCOL_VERSION, '2025-06-18', '2025-03-26', '2024-11-05', '2024-10-07'];

/**
Expand Down
Loading