Project a document to one MCP protocol version

A single-version projection validates the source, keeps the declarations whose effective scope includes the protocol version, removes their scopes, and keeps everything else unchanged: security forms, examples, client requirements, tags, extensions, and the components still referenced.

Requirement

An Effective Protocol View is a valid document for one protocol version that keeps the applicable declarations and preserves their content, security semantics, and referenced components.

Details

Rule ID: mcpdesc.view.projection
Owner: mcpdesc
Surface: Effective Protocol View
Kind: mcpdesc-semantic
Requirement level: must
Protocol versions: independent of the MCP protocol version
Status: delegated · Enforcement: external

Required by

• MCP Description 0.9.0, Section 4.12, and the view requirements of Sections 3 to 17
  • 4. Versioning: req-view-projection
  • 4. Versioning: req-view-projection-transports
  • 3. Document Structure: req-security-empties-preserved
  • 7. Security: req-security-empty-distinction
  • 7. Security: req-security-projection
  • 15. Serialization: req-serialization-empty-values-preserved
  • 9. Tools: req-tool-example-views-preserved
  • 9. Tools: req-interaction-views-preserved
  • 8. Capabilities: req-client-requirements-views
  • 10. Resources and Resource Templates: req-resource-example-views
  • 10. Resources and Resource Templates: req-template-completion-views
  • 11. Prompts: req-prompt-example-views
  • 11. Prompts: req-prompt-completion-views
  • 13. Tags: req-tags-views
  • 14. Specification Extensions: req-extension-views
  • 17. Reusable Components and Local References: req-component-pruning

Notes

Checked by the cases in view-fixtures/, which scripts/test-view-fixtures.mjs recomputes with the reference operations of scripts/mcpdesc-views.mjs. Implementations such as @mcpdesc/core must pass them.

Examples

View succeeds

Source: view-fixtures/view-client-requirements-2026-07-28.json · Selected: /expected

"expected/view-client-requirements-2026-07-28.json"

View succeeds

Source: view-fixtures/view-completion-examples-2026-07-28.json · Selected: /expected

"expected/view-completion-examples-2026-07-28.json"

View succeeds

Source: view-fixtures/view-component-pruning-2026-07-28.json · Selected: /expected

"expected/view-component-pruning-2026-07-28.json"

View succeeds

Source: view-fixtures/view-prompt-examples-2026-07-28.json · Selected: /expected

"expected/view-prompt-examples-2026-07-28.json"

View succeeds

Source: view-fixtures/view-protocol-scoped-primitives-2025-11-25.json · Selected: /expected

"expected/view-protocol-scoped-primitives-2025-11-25.json"

View succeeds

Source: view-fixtures/view-protocol-scoped-primitives-2026-07-28.json · Selected: /expected

"expected/view-protocol-scoped-primitives-2026-07-28.json"

View succeeds

Source: view-fixtures/view-resource-examples-2026-07-28.json · Selected: /expected

"expected/view-resource-examples-2026-07-28.json"

View succeeds

Source: view-fixtures/view-security-forms-2025-11-25.json · Selected: /expected

"expected/view-security-forms-2025-11-25.json"

View succeeds

Source: view-fixtures/view-security-forms-2026-07-28.json · Selected: /expected

"expected/view-security-forms-2026-07-28.json"

View succeeds

Source: view-fixtures/view-specification-extensions-2025-11-25.json · Selected: /expected

"expected/view-specification-extensions-2025-11-25.json"

View succeeds

Source: view-fixtures/view-tool-interaction-examples-2025-11-25.json · Selected: /expected

"expected/view-tool-interaction-examples-2025-11-25.json"

View fails

Source: view-fixtures/view-protocol-version-not-declared.json · Selected: /expectedFailure

"req-view-projection"

View fails

Source: view-fixtures/view-source-invalid.json · Selected: /expectedFailure

"req-view-projection"

Rule Source Code

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