fix: ignore SSE retry: field to prevent McpTransportException - #1082
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chao6118 wants to merge 1 commit into
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fix: ignore SSE retry: field to prevent McpTransportException#1082chao6118 wants to merge 1 commit into
chao6118 wants to merge 1 commit into
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The SSE specification includes 'retry:' as a valid field for setting the reconnection interval. However, the SseLineSubscriber treats any unrecognized line as an error, causing McpTransportException when MCP servers (e.g., rmcp-based servers like SurrealDB) emit retry directives in SSE responses. This fix adds a handler that silently ignores 'retry:' lines, matching the existing behaviour for ':' comment lines. Related: servers using rmcp (Rust MCP SDK) send 'retry: 3000' by default, which triggers this error and breaks Streamable HTTP connections to SurrealDB and other rmcp-based MCP servers.
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Problem
The SSE specification includes
retry:as a valid field.SseLineSubscriber.hookOnNext()treats unrecognized lines as errors, crashing when servers emit retry directives.Reproduction
Connect to a SurrealDB MCP server (rmcp-based) via Streamable HTTP. The server sends
retry: 3000in SSE, causing:Fix
Ignore
retry:lines silently, same as:comments. The W3C SSE spec definesretry:as a valid field.Related
#685 (SSE comment handling)