MCP Documentation Server

[Model Context Protocol home page](https://modelcontextprotocol.io/) Version 2025-06-18 (latest) Search... Ctrl K Search... Navigation Utilities Progress [Documentation](https://modelcontextprotocol.io/docs/getting-started/intro) [Specification](https://modelcontextprotocol.io/specification/2025-06-18) [Community](https://modelcontextprotocol.io/community/communication) [About MCP](https://modelcontextprotocol.io/about) On this page - [Progress Flow](https://modelcontextprotocol.io/specification/2025-06-18/basic/utilities/progress#progress-flow) - [Behavior Requirements](https://modelcontextprotocol.io/specification/2025-06-18/basic/utilities/progress#behavior-requirements) - [Implementation Notes](https://modelcontextprotocol.io/specification/2025-06-18/basic/utilities/progress#implementation-notes) **Protocol Revision**: 2025-06-18 The Model Context Protocol (MCP) supports optional progress tracking for long-running operations through notification messages. Either side can send progress notifications to provide updates about operation status. <h2>Progress Flow</h2> When a party wants to _receive_ progress updates for a request, it includes a `progressToken` in the request metadata. - Progress tokens **MUST** be a string or integer value - Progress tokens can be chosen by the sender using any means, but **MUST** be unique across all active requests. Copy ``` {\n \"jsonrpc\": \"2.0\",\n \"id\": 1,\n \"method\": \"some_method\",\n \"params\": {\n \"_meta\": {\n \"progressToken\": \"abc123\"\n }\n }\n}\n ``` The receiver **MAY** then send progress notifications containing: - The original progress token - The current progress value so far - An optional “total” value - An optional “message” value Copy ``` {\n \"jsonrpc\": \"2.0\",\n \"method\": \"notifications/progress\",\n \"params\": {\n \"progressToken\": \"abc123\",\n \"progress\": 50,\n \"total\": 100,\n \"message\": \"Reticulating splines...\"\n }\n}\n ``` - The `progress` value **MUST** increase with each notification, even if the total is unknown. - The `progress` and the `total` values **MAY** be floating point. - The `message` field **SHOULD** provide relevant human readable progress information. <h2>Behavior Requirements</h2> 1. Progress notifications **MUST** only reference tokens that: - Were provided in an active request - Are associated with an in-progress operation 2. Receivers of progress requests **MAY** : - Choose not to send any progress notifications - Send notifications at whatever frequency they deem appropriate - Omit the total value if unknown <h2>Implementation Notes</h2> - Senders and receivers **SHOULD** track active progress tokens - Both parties **SHOULD** implement rate limiting to prevent flooding - Progress notifications **MUST** stop after completion