refactor: create McpServer per session for reliable HTTP reconnection#299
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refactor: create McpServer per session for reliable HTTP reconnection#299
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The MCP SDK expects one McpServer per transport connection. The previous code shared a single instance across all HTTP sessions, which meant reconnecting clients hit "Already connected to a transport" errors because the old session's binding was never released. Now each StreamableHTTP and SSE session gets its own McpServer instance, matching the pattern from the SDK documentation. Sessions are tracked in a unified map with their transport and server for cleanup.
The MCP SDK expects one McpServer per transport connection. The previous code shared a single instance across all HTTP sessions, which meant reconnecting clients hit "Already connected to a transport" errors because the old session's binding was never released. Now each StreamableHTTP and SSE session gets its own McpServer instance, matching the pattern from the SDK documentation. Sessions are tracked in a unified map with their transport and server for cleanup. Also adds reconnection tests including a dirty-close scenario that reproduces the original bug, and promotes the multi-client test from it.fails to it (now works with per-session servers).
medyas
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Mar 22, 2026
… errors - Adopt upstream GLips#299 per-session McpServer architecture: each HTTP session gets its own McpServer instance, fixing "Already connected" errors on client reconnection. Preserved fork additions (health endpoint, metrics, caching support). - fetchWithRetry: throw combined error with both fetch and curl failure reasons instead of silently discarding curl context. - writeLogs: switch from sync fs to async fs/promises to avoid blocking the event loop when writing large debug files in development mode. - style.ts: fix let→const for never-reassigned backgroundRepeat.
compassalessandrolorenz
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Mar 25, 2026
…GLips#299) * refactor: create McpServer per session instead of sharing one instance The MCP SDK expects one McpServer per transport connection. The previous code shared a single instance across all HTTP sessions, which meant reconnecting clients hit "Already connected to a transport" errors because the old session's binding was never released. Now each StreamableHTTP and SSE session gets its own McpServer instance, matching the pattern from the SDK documentation. Sessions are tracked in a unified map with their transport and server for cleanup. * refactor: create McpServer per session instead of sharing one instance The MCP SDK expects one McpServer per transport connection. The previous code shared a single instance across all HTTP sessions, which meant reconnecting clients hit "Already connected to a transport" errors because the old session's binding was never released. Now each StreamableHTTP and SSE session gets its own McpServer instance, matching the pattern from the SDK documentation. Sessions are tracked in a unified map with their transport and server for cleanup. Also adds reconnection tests including a dirty-close scenario that reproduces the original bug, and promotes the multi-client test from it.fails to it (now works with per-session servers).
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Summary
McpServerinstance per StreamableHTTP/SSE session instead of sharing one across all connectionssessionsmap that stores both the transport and its associated serverit.failstoit(now works with per-session servers)Test plan