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The overview's Key Features and Supported Methods listed `roots`, `sampling`, and `logging/setLevel` with no deprecation marking, while their own pages carry the SEP-2577 warnings, presenting a current-looking feature surface to a reader skimming the overview. The five entries now carry the pages' "deprecated as of 2026-07-28" wording; `elicitation/create` stays unmarked - it is not deprecated, and the modern lifecycle keeps carrying it as requests embedded per the multi round-trip requests pattern.
53 lines
3 KiB
Markdown
53 lines
3 KiB
Markdown
---
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layout: default
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title: Overview
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nav_order: 1
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permalink: /server/
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redirect_from:
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- /building-servers.html
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- /building-servers/
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---
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# Building an MCP Server
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The `MCP::Server` class is the core component that handles JSON-RPC requests and responses.
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It implements the Model Context Protocol specification, handling model context requests and responses.
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## Key Features
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- Implements JSON-RPC 2.0 message handling
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- Supports protocol initialization and capability negotiation
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- Manages tool registration and invocation
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- Supports prompt registration and execution
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- Supports resource registration and retrieval
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- Supports stdio and Streamable HTTP (including SSE) transports
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- Supports notifications for list changes (tools, prompts, resources)
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- Supports roots (server-to-client filesystem boundary queries; deprecated as of 2026-07-28)
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- Supports sampling (server-to-client LLM completion requests; deprecated as of 2026-07-28)
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- Supports cursor-based pagination for list operations
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- Supports cancellation of in-flight requests on both server and client (notifications/cancelled)
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## Supported Methods
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- `initialize` - Initializes the protocol and returns server capabilities
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- `server/discover` - Sessionless capability discovery (MCP 2026-07-28, SEP-2575): returns the server's capabilities
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before `initialize` and without an `Mcp-Session-Id`, and anchors the stateless modern lifecycle; see [Discovery](/server/discover/)
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- `subscriptions/listen` - Long-lived notification subscription stream (MCP 2026-07-28, SEP-2575), replacing the legacy HTTP GET
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listening stream; see [Subscriptions](/server/subscriptions/)
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- Multi round-trip `input_required` results (MCP 2026-07-28, SEP-2322): handlers return `MCP::Server::InputRequiredResult` to ask
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the client for additional input instead of performing a server-initiated request; see [Multi Round-Trip Requests](/server/mrtr/)
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- `ping` - Simple health check
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- `logging/setLevel` - Configures the minimum log level for the server (deprecated as of 2026-07-28)
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- `tools/list` - Lists all registered tools and their schemas
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- `tools/call` - Invokes a specific tool with provided arguments
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- `prompts/list` - Lists all registered prompts and their schemas
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- `prompts/get` - Retrieves a specific prompt by name
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- `resources/list` - Lists all registered resources and their schemas
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- `resources/read` - Retrieves a specific resource by name
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- `resources/templates/list` - Lists all registered resource templates and their schemas
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- `resources/subscribe` - Subscribes to updates for a specific resource
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- `resources/unsubscribe` - Unsubscribes from updates for a specific resource
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- `completion/complete` - Returns autocompletion suggestions for prompt arguments and resource URIs
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- `roots/list` - Requests filesystem roots from the client (server-to-client; deprecated as of 2026-07-28)
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- `sampling/createMessage` - Requests LLM completion from the client (server-to-client; deprecated as of 2026-07-28)
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- `elicitation/create` - Requests user input from the client (server-to-client)
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