c9d36b04bf
Three pages carried names the 2026-07-28 specification does not use: "Multi-Round-Trip Results" for the pattern the specification titles Multi Round-Trip Requests (MRTR) and serves at basic/patterns/mrtr - the results are the `InputRequiredResult` wire type, not the feature - plus "Completions" for the utility the specification titles Completion, and "Notification Subscriptions" for the pattern it titles Subscriptions. Retitle the three pages to the specification's names, move them to /server/mrtr/ and /client/mrtr/, /server/completion/, and /server/subscriptions/ following the specification's slugs, update every internal reference, and keep the URLs published with v1.3.0 working via jekyll-redirect-from. The Discovery page keeps its title but moves from /server/discovery/ to /server/discover/, matching the specification's slug and the `server/discover` RPC, with its published URL redirected the same way.
68 lines
2.8 KiB
Markdown
68 lines
2.8 KiB
Markdown
---
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layout: default
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title: Notifications
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nav_order: 11
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---
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# Notifications
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The server supports sending notifications to clients when lists of tools, prompts, or resources change. This enables real-time updates without polling.
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## Notification Methods
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The server provides the following notification methods:
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- `notify_tools_list_changed` - Send a notification when the tools list changes
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- `notify_prompts_list_changed` - Send a notification when the prompts list changes
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- `notify_resources_list_changed` - Send a notification when the resources list changes
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- `notify_log_message` - Send a structured logging notification message (see [Logging](/server/logging/))
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## Session Scoping
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When using Streamable HTTP transport with multiple clients, each client connection gets its own session. Notifications are scoped as follows:
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- **`report_progress`** and **`notify_log_message`** called via [`server_context`](/server/server-context/) inside a tool handler are automatically sent only to the requesting client.
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No extra configuration is needed.
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- **`notify_tools_list_changed`**, **`notify_prompts_list_changed`**, and **`notify_resources_list_changed`** are always broadcast to all connected clients,
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as they represent server-wide state changes. These should be called on the `server` instance directly.
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On the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) (MCP 2026-07-28), clients receive these broadcasts through the `subscriptions/listen` stream;
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see [Subscriptions](/server/subscriptions/).
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## Notification Format
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Notifications follow the JSON-RPC 2.0 specification and use these method names:
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- `notifications/tools/list_changed`
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- `notifications/prompts/list_changed`
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- `notifications/resources/list_changed`
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- `notifications/cancelled` (see [Cancellation](/server/cancellation/))
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- `notifications/progress` (see [Progress](/server/progress/))
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- `notifications/message` (see [Logging](/server/logging/))
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## Broadcasting a List Change
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Call the matching `notify_*` method after changing a server-wide list:
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```ruby
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server = MCP::Server.new(name: "my_server")
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# Default Streamable HTTP - session oriented
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transport = MCP::Server::Transports::StreamableHTTPTransport.new(server)
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# When tools change, notify clients
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server.define_tool(name: "new_tool") { |**args| MCP::Tool::Response.new([{ type: "text", text: "ok" }]) }
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server.notify_tools_list_changed
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# When prompts change, notify clients
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server.define_prompt(name: "new_prompt") do |args, server_context:|
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MCP::Prompt::Result.new(messages: [])
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end
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server.notify_prompts_list_changed
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# When resources change, notify clients
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server.define_resource(uri: "resource://new", name: "new_resource", mime_type: "text/plain") do
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[MCP::Resource::TextContents.new(uri: "resource://new", mime_type: "text/plain", text: "contents")]
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end
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server.notify_resources_list_changed
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```
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