Fixed issue modelcontextprotocol#326 - MCP client with npx not working when env parameter of StdioServerParameters is set

maxguru · web-flow · commit 785e09fa8130 · 2025-03-20T05:38:32.000Z
diff --git a/src/mcp/client/stdio.py b/src/mcp/client/stdio.py
@@ -103,7 +103,7 @@ async def stdio_client(server: StdioServerParameters):
 
     process = await anyio.open_process(
         [server.command, *server.args],
-        env=server.env if server.env is not None else get_default_environment(),
+        env={**get_default_environment(), **server.env} if server.env is not None else get_default_environment(),
         stderr=sys.stderr,
         cwd=server.cwd,
     )

Original file line number	Diff line number	Diff line change
`@@ -103,7 +103,7 @@ async def stdio_client(server: StdioServerParameters):`
`103`	`103`
`104`	`104`	`process = await anyio.open_process(`
`105`	`105`	`[server.command, *server.args],`
`106`		`- env=server.env if server.env is not None else get_default_environment(),`
	`106`	`+ env={get_default_environment(), server.env} if server.env is not None else get_default_environment(),`
`107`	`107`	`stderr=sys.stderr,`
`108`	`108`	`cwd=server.cwd,`
`109`	`109`	`)`