The MCP Lifecycle
At the application level, an MCP integration usually goes through a predictable sequence even though the 2026 protocol core is now stateless.
1. Establish reachability
For stdio, the client starts or connects to a local process. For HTTP, it needs a reachable server URL and any required authentication headers.
2. Discover what is available
The client can discover server capabilities and list tools, prompts, or resources. List results in the 2026 specification can carry cache guidance, allowing clients to avoid repeated catalog fetches.
3. Expose selected capabilities to the model
The host should not blindly expose everything. Filter to the tools relevant to the agent's task, especially when multiple servers publish overlapping or sensitive capabilities.
4. Execute calls
The model requests a tool through the agent runtime. The MCP client routes the call to the server, the server performs business logic, and the result is returned to the host.
5. Handle approval and policy
Sensitive actions may pause for human approval. OpenAI's Agents SDK supports approval policies for local and hosted MCP tools, which is a useful pattern even if you use a different runtime.
6. Retry, cache, and observe
Networked MCP calls need ordinary distributed-systems discipline: timeouts, idempotency where appropriate, retry boundaries, tracing, metrics, and careful caching.
7. Shutdown
Local process transports need clean process termination. HTTP deployments typically rely on normal connection lifecycle and server infrastructure rather than protocol sessions.