v2: move registered primitives to classes

[KKonstantinov]

Refactor RegisteredTool, RegisteredPrompt, RegisteredResource to proper classes

Motivation and Context

The RegisteredTool, RegisteredPrompt, RegisteredResource, and RegisteredResourceTemplate types were previously plain object types. This refactoring converts them to proper classes with:

• Private fields using # syntax for encapsulation
• Getter methods for read-only access to properties
• Simplified update() method using Object.assign for protocol fields
• Constructor callbacks pattern for communicating with McpServer
• New getter methods on McpServer to retrieve all registered items
• Added icons support to RegisteredTool (for parity with protocol Tool type)

How Has This Been Tested?

• pnpm lint:fix:all - passes
• pnpm typecheck:all - passes
• pnpm test:all - 487 tests passing

Breaking Changes

Yes, users will need to update their code:

v1 (update field)	v2 (update field)	Applies to
paramsSchema	inputSchema	RegisteredTool.update()
callback	handler	RegisteredTool.update()

Note: In v1, the RegisteredTool.update() method used paramsSchema which did not match the inputSchema field used in registerTool(). This inconsistency has been fixed in v2 — both now use inputSchema.

New getter methods on McpServer:

• mcpServer.tools → ReadonlyMap<string, RegisteredTool>
• mcpServer.prompts → ReadonlyMap<string, RegisteredPrompt>
• mcpServer.resources → ReadonlyMap<string, RegisteredResource>
• mcpServer.resourceTemplates → ReadonlyMap<string, RegisteredResourceTemplate>

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

New file structure

packages/server/src/server/primitives/
├── index.ts          # Re-exports all classes and types
├── types.ts          # Shared callback types (OnUpdate, OnRename, OnRemove)
├── tool.ts           # RegisteredTool class
├── prompt.ts         # RegisteredPrompt class
├── resource.ts       # RegisteredResource class
└── resourceTemplate.ts # RegisteredResourceTemplate class + ResourceTemplate class

Key design decisions

1. Private fields with #: Uses JavaScript private class fields for true encapsulation
2. Protocol fields grouped: Protocol-derived fields stored in #protocolFields object, SDK-specific fields stored separately
3. Simplified update(): Uses Object.assign(this.#protocolFields, protocolUpdates) so new protocol fields automatically work
4. Constructor callbacks: Classes receive onUpdate, onRename, onRemove callbacks for communicating state changes to McpServer
5. Type derivation with Omit: Config types derived from protocol types using Omit to automatically include new fields

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commit: 3dbc7c0

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Latest commit: 3dbc7c0

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