[Doc] Clarify that StreamableHTTPTransport requires a single-process server#290
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koic merged 1 commit intomodelcontextprotocol:mainfrom Apr 3, 2026
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…s server ## Motivation and Context `StreamableHTTPTransport` stores session and SSE stream state in memory using instance variables (`@sessions`, `@mutex`). This design requires all HTTP requests to be handled within the same process to share state. Process-based servers like Unicorn fork separate worker processes that do not share memory, which breaks session management and SSE connections. This requirement is not obvious from the current documentation. ## How Has This Been Tested? Documentation-only change. ## Breaking Changes None.
atesgoral
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Apr 3, 2026
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We could probably introduce a session store adapter later |
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koic
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## Motivation and Context PR #290 documented that `StreamableHTTPTransport` requires a single-process server. However, when running multiple server instances behind a load balancer, requests for the same session must be routed to the same instance since session state is stored in memory. This adds a note about using sticky sessions (session affinity) based on the `Mcp-Session-Id` header. ## How Has This Been Tested? Documentation-only change. ## Breaking Changes None.
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Motivation and Context
StreamableHTTPTransportstores session and SSE stream state in memory using instance variables (@sessions,@mutex). This design requires all HTTP requests to be handled within the same process to share state.Process-based servers like Unicorn fork separate worker processes that do not share memory, which breaks session management and SSE connections. This requirement is not obvious from the current documentation.
How Has This Been Tested?
Documentation-only change.
Breaking Changes
None.
Types of changes
Checklist