User context in the Model Context Protocol (MCP) is maintained across sessions through a combination of session identifiers, server-side storage, and client-server coordination. When a user initiates a session, MCP assigns a unique session ID that acts as a reference to their interaction history and contextual data. This ID is stored on the server and shared with the client (e.g., a user’s device or application). During subsequent sessions, the client sends this ID back to the server, allowing the system to retrieve and apply the stored context. This approach ensures continuity without requiring the client to manage large amounts of data locally.
The protocol relies on server-side databases or caching systems to store context data tied to each session ID. For example, if a user interacts with an MCP-powered chatbot, their conversation history, preferences, and temporary variables (like a partially completed form) are saved under their session ID. When the user returns, the client sends the ID, and the server reconstructs the context from stored data. This design minimizes client-side complexity and centralizes context management, making it easier to update or scale the system. Developers can configure storage duration, with options like time-based expiration or manual deletion to balance performance and privacy.
A practical example involves a user resuming a task across devices. Suppose a user starts a workflow on a mobile app (session A) and later switches to a desktop (session B). If both devices share the same session ID (e.g., via user authentication), the server can synchronize context between sessions. This ensures the desktop session picks up where the mobile session left off. Developers must ensure secure handling of session IDs—using HTTPS, encryption, or tokenization—to prevent unauthorized access. By decoupling context storage from client devices, MCP simplifies maintaining stateful interactions while keeping clients lightweight and interoperable.