Skip to content
{mcpdesc}

4. Versioning

4. Versioning

Section titled “4. Versioning”

4.1 The mcpdesc Field

Section titled “4.1 The mcpdesc Field”

Every MCP Description document MUST include a mcpdesc property at the root level. This property declares which version of this specification the document conforms to.

{
  "mcpdesc": "0.7.0"
}

4.2 Version Format

Section titled “4.2 Version Format”

The mcpdesc value MUST be a string matching a published version of this specification. The current version is "0.7.0".

The specification uses Semantic Versioning for its own version numbers:

  • Major version changes indicate breaking changes to the document structure
  • Minor version changes add new optional features in a backward-compatible manner
  • Patch version changes address errata or clarifications without structural changes

4.3 Version Compatibility

Section titled “4.3 Version Compatibility”

Implementations SHOULD support the latest specification version. Implementations MAY support multiple versions.

When processing a document, implementations MUST check the mcpdesc value and:

  • Accept documents with a recognized mcpdesc version
  • Reject documents with an unrecognized mcpdesc version or provide a clear warning

4.4 Forward Compatibility

Section titled “4.4 Forward Compatibility”

Implementations SHOULD ignore unknown properties within known objects. This allows documents authored against a newer minor version to be partially processed by implementations supporting an older minor version of the same major version.

4.5 Relationship to MCP Protocol Versions

Section titled “4.5 Relationship to MCP Protocol Versions”

The mcpdesc version is independent of the MCP protocol version. The MCP protocol version implemented by a server is declared in info.protocolVersion.

A single MCP Description specification version MAY support documents describing servers implementing different MCP protocol versions.