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{mcpdesc}

15. Conformance

15. Conformance

Section titled “15. Conformance”

15.1 Document Conformance

Section titled “15.1 Document Conformance”

A conforming MCP Description document MUST:

  1. Be a valid JSON document (Section 14).
  2. Include the mcpdesc property with a recognized specification version (Section 4).
  3. Include the info object with at least name and version (Section 5).
  4. Include the transports array with at least one transport object (Section 6).
  5. Include at least one of: tools, resources, resourceTemplates, or prompts (Section 3.3).
  6. Validate against the JSON Schema for the declared mcpdesc version.
  7. Not contain unknown properties at the root level except specification extensions matching ^x-.

15.2 Implementation Conformance

Section titled “15.2 Implementation Conformance”

A conforming implementation (tool, validator, or platform) MUST:

  1. Accept and correctly parse documents conforming to this specification.
  2. Reject documents that fail the requirements in Section 15.1.
  3. Ignore unrecognized specification extensions without error (Section 13.4).
  4. Preserve specification extensions when processing and re-serializing documents (Section 13.4).

A conforming implementation SHOULD:

  1. Support at least the current specification version.
  2. Provide clear error messages when rejecting non-conforming documents.
  3. Support JSON Schema validation against the published schema.

15.3 Partial Conformance

Section titled “15.3 Partial Conformance”

Implementations that support only a subset of the specification (e.g., only tools, or only a specific transport type) SHOULD document their limitations clearly.

15.4 Versioned Conformance

Section titled “15.4 Versioned Conformance”

Conformance is assessed against a specific specification version. An implementation claiming conformance MUST state which mcpdesc version(s) it supports.

Appendix A: Icon Object

Section titled “Appendix A: Icon Object”

The Icon object is used throughout the specification for UI display.

Property Type Required Description
src string (URI) Yes URI pointing to an icon resource (HTTP/HTTPS URL or data: URI).
mimeType string No MIME type override (e.g., "image/png", "image/svg+xml").
sizes array<string> No Sizes at which the icon can be used (e.g., "48x48", "96x96", "any").
theme string No Theme this icon is designed for: "light" or "dark".

Clients MUST support image/png and image/jpeg. Clients SHOULD also support image/svg+xml and image/webp.

Appendix B: Complete Example

Section titled “Appendix B: Complete Example”

See examples/full-featured.yaml for a complete MCP Description document demonstrating all features of this specification.

Appendix C: JSON Schema

Section titled “Appendix C: JSON Schema”

The normative JSON Schema for this specification version is available at:

Appendix D: References

Section titled “Appendix D: References”

Normative References

Section titled “Normative References”
  • [RFC 2119] Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels”, RFC 2119, March 1997.
  • [RFC 3986] Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax”, RFC 3986, January 2005.
  • [RFC 6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M., and D. Orchard, “URI Template”, RFC 6570, March 2012.
  • [RFC 8259] Bray, T., “The JavaScript Object Notation (JSON) Data Interchange Format”, RFC 8259, December 2017.
  • [JSON Schema] Wright, A., Andrews, H., Hutton, B., “JSON Schema: A Media Type for Describing JSON Documents”, draft-bhutton-json-schema-01, June 2022.

Informative References

Section titled “Informative References”