Use a concrete URI that expands the template

A Resource Template example records the concrete requested URI, which must be an RFC 6570 expansion of the containing template. Check the template and URI together, including examples reached through components. Matching a URI does not require network retrieval.

Requirement

A Resource Template example uri is a valid RFC 6570 expansion of the template.

Details

Rule ID: mcpdesc.resource-template.example.expansion
Owner: mcpdesc
Surface: Resource Template example · Path: uri
Kind: mcpdesc-semantic
Requirement level: must
Protocol versions: independent of the MCP protocol version
Status: internal · Enforcement: internal

Required by

• MCP Description 0.9.0, Section 10.4.3
  • 10. Resources and Resource Templates: req-resource-template-example-expansion

Based on

• Tier 2 — Normative referenced standards: RFC 6570, URI Template
  • https://www.rfc-editor.org/rfc/rfc6570#section-3

Examples

Valid example

Source: expected-valid/named-resource-examples.json · Selected: /resourceTemplates/0

{
  "protocolVersions": [
    "2026-07-28"
  ],
  "uriTemplate": "chess://games/{game_id}",
  "name": "game_detail",
  "mimeType": "application/json",
  "examples": {
    "sample-game": {
      "uri": "chess://games/example-1234",
      "result": {
        "resultType": "complete",
        "ttlMs": 300000,
        "cacheScope": "public",
        "contents": [
          {
            "uri": "chess://games/example-1234",
            "mimeType": "application/json",
            "text": "{\"id\":\"example-1234\",\"result\":\"1-0\"}"
          }
        ]
      }
    }
  }
}

Invalid example

Source: expected-invalid/resource-example-result-semantics.json · Selected: /resourceTemplates/0/examples/not-an-expansion

{
  "uri": "chess://players/example-1234",
  "result": {
    "contents": [
      {
        "uri": "chess://players/example-1234",
        "text": "wrong route"
      }
    ]
  }
}

Invalid example

Source: expected-invalid/component-contextual-examples.json · Selected: /components/resourceTemplateExamples/bad-uri

{
  "uri": "data://other/1",
  "result": {
    "resultType": "complete",
    "ttlMs": 1,
    "cacheScope": "private",
    "contents": [
      {
        "uri": "data://other/1",
        "text": "wrong"
      }
    ]
  }
}

Rule Source Code

resource.yaml at immutable tag v0.9.0-rc.3.