§ tools · storyline
MCP Spec v2025-06-18
Model Context Protocol publishes spec revision 2025-06-18, with SDK adoption at individual maintainers' pace and prior versions remaining valid during transition.
This release marks the initial 2025-06-18 revision of the Model Context Protocol. For a detailed overview of changes, see 2025-06-18 changelog. _To users and implementors:_ note that SDKs will adopt this version at their own pace, and the prior version of the spec may remain in use for an undetermined amount of time.
The spec describes how clients and servers perform version negotiation with one another, permitting backwards and forwards compatibility.
§ sources1 publication · timeline below
- github.comspecification 2025-06-18primary