langchain-ai/langchainjs @langchain/mcp-adapters@2.0.1

on GitHub

Patch Changes

• #11804 0552450 Thanks @byhow! - Keep the SDK error as cause after an HTTP→SSE fallback. When a Streamable HTTP connection falls back to SSE and the SSE attempt fails, the thrown MCPClientError now has the SSE attempt's SDK error (an UnauthorizedError, or the SSE 401) as its cause, one level down as for a direct HTTP or SSE connection, instead of a second MCPClientError. Code that checks UnauthorizedError.isInstance(error.cause), such as an OAuth login handler, now works for SSE-only servers too.

• #11845 1b5ac16 Thanks @hntrl! - Use a single underscore between MCP server names and tool names (server_tool instead of server__tool). The separator for additionalToolNamePrefix remains unchanged (mcp__server_tool).