UV cannot be detected

[ChiehHsi333]

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[msanatan]

@ChiehHsi333 there's not enough info for this ticket to be useful.

What's your OS, how did you install uv, what version are you using... you have to provide details so we can reproduce and fix

[ChiehHsi333]

@ChiehHsi333 there's not enough info for this ticket to be useful.

What's your OS, how did you install uv, what version are you using... you have provide details so we can reproduce and fix

Thank you for the reply. I resolved the uv issue with Cursor, but the server won’t launch today. I'm using Windows 11, Unity 6000.0.43f1 editor.

MCP-FOR-UNITY: [WebSocket] Connection failed: Unable to connect to the remote server
UnityEngine.Debug:LogError (object)
MCPForUnity.Editor.Helpers.McpLog:Error (string) (at E:/Anity/unity-mcp-main/MCPForUnity/Editor/Helpers/McpLog.cs:50)
MCPForUnity.Editor.Services.Transport.Transports.WebSocketTransportClient/d__34:MoveNext () (at E:/Anity/unity-mcp-main/MCPForUnity/Editor/Services/Transport/Transports/WebSocketTransportClient.cs:233)
System.Threading._ThreadPoolWaitCallback:PerformWaitCallback ()

Cursor debug log:
{"id":"log_1766472280873_onstart_clicked","timestamp":1766472280873,"location":"McpConnectionSection.cs:299","message":"OnStartLocalHttpServerClicked entry","data":{},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1,S2,S3"}
{"id":"log_1766472280877_start_entry","timestamp":1766472280877,"location":"ServerManagementService.cs:160","message":"StartLocalHttpServer entry","data":{},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1"}
{"id":"log_1766472280877_start_cmd","timestamp":1766472280877,"location":"ServerManagementService.cs:172","message":"Command built","data":{"command":"C:/Users/Administrator/.local/bin/uv.exe mcp-for-unity --transport http --http-url http://localhost:8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1"}
{"id":"log_1766472280878_entry","timestamp":1766472280878,"location":"ServerManagementService.cs:220","message":"StopLocalHttpServer entry","data":{"method":"StopLocalHttpServer"},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,B,C,D,E"}
{"id":"log_1766472280878_url","timestamp":1766472280878,"location":"ServerManagementService.cs:223","message":"HTTP URL retrieved","data":{"httpUrl":"http://localhost:8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"B"}
{"id":"log_1766472280878_islocal","timestamp":1766472280878,"location":"ServerManagementService.cs:224","message":"IsLocalUrl check result","data":{"isLocal":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"B"}
{"id":"log_1766472280878_port","timestamp":1766472280878,"location":"ServerManagementService.cs:232","message":"Port extracted from URI","data":{"port":8080},"sessionId":"debug-session","runId":"run1","hypothesisId":"C"}
{"id":"log_1766472280880_getpid_entry","timestamp":1766472280880,"location":"ServerManagementService.cs:262","message":"GetProcessIdForPort entry","data":{"port":8080,"platform":"WindowsEditor"},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,E"}
{"id":"log_1766472280919_netstat","timestamp":1766472280919,"location":"ServerManagementService.cs:272","message":"netstat command executed","data":{"success":false,"stdout":"","stderr":"","command":"/c netstat -ano | findstr :8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"E"}
{"id":"log_1766472280919_netstat_nomatch","timestamp":1766472280919,"location":"ServerManagementService.cs:279","message":"netstat returned no matches","data":{"command":"/c netstat -ano | findstr :8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"A"}
{"id":"log_1766472280919_getpid_return_neg1","timestamp":1766472280919,"location":"ServerManagementService.cs:319","message":"GetProcessIdForPort returning -1","data":{"returnValue":-1},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,D"}
{"id":"log_1766472280919_pid","timestamp":1766472280919,"location":"ServerManagementService.cs:242","message":"GetProcessIdForPort result","data":{"pid":-1,"port":8080},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,D,E"}
{"id":"log_1766472280920_return_false_nopid","timestamp":1766472280920,"location":"ServerManagementService.cs:252","message":"Returning false - No process found","data":{"returnValue":false,"pid":-1},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,D"}
{"id":"log_1766472280920_uv_exists","timestamp":1766472280920,"location":"ServerManagementService.cs:176","message":"uv executable presence","data":{"uvPath":"C:/Users/Administrator/.local/bin/uv.exe","exists":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"S4"}
{"id":"log_1766472282210_start_user_choice","timestamp":1766472282210,"location":"ServerManagementService.cs:185","message":"User dialog choice","data":{"confirmed":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"S3"}
{"id":"log_1766472282218_start_success","timestamp":1766472282218,"location":"ServerManagementService.cs:197","message":"Process start invoked","data":{"fileName":"cmd.exe","arguments":"/c start "MCP Server" cmd.exe /k "C:/Users/Administrator/.local/bin/uv.exe mcp-for-unity --transport http --http-url http://localhost:8080\""},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1"}
{"id":"log_1766472282218_onstart_result","timestamp":1766472282218,"location":"McpConnectionSection.cs:308","message":"StartLocalHttpServer returned","data":{"started":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1,S2,S3"}
{"id":"log_1766472296868_ws_start","timestamp":1766472296868,"location":"WebSocketTransportClient.cs:102","message":"StartAsync entry","data":{"baseUrl":"http://localhost:8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4"}
{"id":"log_1766472296871_ws_endpoint","timestamp":1766472296871,"location":"WebSocketTransportClient.cs:112","message":"WebSocket endpoint built","data":{"endpoint":"ws://localhost:8080/hub/plugin"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1"}
{"id":"log_1766472296875_ws_connect_begin","timestamp":1766472296875,"location":"WebSocketTransportClient.cs:226","message":"ConnectAsync begin","data":{"endpoint":"ws://localhost:8080/hub/plugin","keepAliveSeconds":15},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4"}
{"id":"log_1766472301006_ws_connect_fail","timestamp":1766472301006,"location":"WebSocketTransportClient.cs:233","message":"ConnectAsync failed","data":{"endpoint":"ws://localhost:8080/hub/plugin","exception":"Unable to connect to the remote server"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4,H5"}
{"id":"log_1766472323961_ws_start","timestamp":1766472323961,"location":"WebSocketTransportClient.cs:102","message":"StartAsync entry","data":{"baseUrl":"http://localhost:8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4"}
{"id":"log_1766472323962_ws_endpoint","timestamp":1766472323962,"location":"WebSocketTransportClient.cs:112","message":"WebSocket endpoint built","data":{"endpoint":"ws://localhost:8080/hub/plugin"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1"}
{"id":"log_1766472323962_ws_connect_begin","timestamp":1766472323962,"location":"WebSocketTransportClient.cs:226","message":"ConnectAsync begin","data":{"endpoint":"ws://localhost:8080/hub/plugin","keepAliveSeconds":15},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4"}
{"id":"log_1766472324682_onstart_clicked","timestamp":1766472324682,"location":"McpConnectionSection.cs:299","message":"OnStartLocalHttpServerClicked entry","data":{},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1,S2,S3"}
{"id":"log_1766472324682_start_entry","timestamp":1766472324682,"location":"ServerManagementService.cs:160","message":"StartLocalHttpServer entry","data":{},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1"}
{"id":"log_1766472324682_start_cmd","timestamp":1766472324682,"location":"ServerManagementService.cs:172","message":"Command built","data":{"command":"C:/Users/Administrator/.local/bin/uv.exe mcp-for-unity --transport http --http-url http://localhost:8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1"}
{"id":"log_1766472324682_entry","timestamp":1766472324682,"location":"ServerManagementService.cs:220","message":"StopLocalHttpServer entry","data":{"method":"StopLocalHttpServer"},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,B,C,D,E"}
{"id":"log_1766472324682_url","timestamp":1766472324682,"location":"ServerManagementService.cs:223","message":"HTTP URL retrieved","data":{"httpUrl":"http://localhost:8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"B"}
{"id":"log_1766472324682_islocal","timestamp":1766472324682,"location":"ServerManagementService.cs:224","message":"IsLocalUrl check result","data":{"isLocal":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"B"}
{"id":"log_1766472324683_port","timestamp":1766472324683,"location":"ServerManagementService.cs:232","message":"Port extracted from URI","data":{"port":8080},"sessionId":"debug-session","runId":"run1","hypothesisId":"C"}
{"id":"log_1766472324683_getpid_entry","timestamp":1766472324683,"location":"ServerManagementService.cs:262","message":"GetProcessIdForPort entry","data":{"port":8080,"platform":"WindowsEditor"},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,E"}
{"id":"log_1766472324719_netstat","timestamp":1766472324719,"location":"ServerManagementService.cs:272","message":"netstat command executed","data":{"success":true,"stdout":" TCP 127.0.0.1:11435 127.0.0.1:8080 SYN_SENT 6796\r\n","stderr":"","command":"/c netstat -ano | findstr :8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"E"}
{"id":"log_1766472324720_lines","timestamp":1766472324720,"location":"ServerManagementService.cs:275","message":"Parsing netstat output","data":{"lineCount":1},"sessionId":"debug-session","runId":"run1","hypothesisId":"E"}
{"id":"log_1766472324720_getpid_return_neg1","timestamp":1766472324720,"location":"ServerManagementService.cs:319","message":"GetProcessIdForPort returning -1","data":{"returnValue":-1},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,D"}
{"id":"log_1766472324720_pid","timestamp":1766472324720,"location":"ServerManagementService.cs:242","message":"GetProcessIdForPort result","data":{"pid":-1,"port":8080},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,D,E"}
{"id":"log_1766472324720_return_false_nopid","timestamp":1766472324720,"location":"ServerManagementService.cs:252","message":"Returning false - No process found","data":{"returnValue":false,"pid":-1},"sessionId":"debug-session","runId":"run1","hypothesisId":"A,D"}
{"id":"log_1766472324721_uv_exists","timestamp":1766472324721,"location":"ServerManagementService.cs:176","message":"uv executable presence","data":{"uvPath":"C:/Users/Administrator/.local/bin/uv.exe","exists":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"S4"}
{"id":"log_1766472326117_start_user_choice","timestamp":1766472326117,"location":"ServerManagementService.cs:185","message":"User dialog choice","data":{"confirmed":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"S3"}
{"id":"log_1766472326120_start_success","timestamp":1766472326120,"location":"ServerManagementService.cs:197","message":"Process start invoked","data":{"fileName":"cmd.exe","arguments":"/c start "MCP Server" cmd.exe /k "C:/Users/Administrator/.local/bin/uv.exe mcp-for-unity --transport http --http-url http://localhost:8080\""},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1"}
{"id":"log_1766472326120_onstart_result","timestamp":1766472326120,"location":"McpConnectionSection.cs:308","message":"StartLocalHttpServer returned","data":{"started":true},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1,S2,S3"}
{"id":"log_1766472328045_ws_connect_fail","timestamp":1766472328045,"location":"WebSocketTransportClient.cs:233","message":"ConnectAsync failed","data":{"endpoint":"ws://localhost:8080/hub/plugin","exception":"Unable to connect to the remote server"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4,H5"}
{"id":"log_1766472329009_ws_start","timestamp":1766472329009,"location":"WebSocketTransportClient.cs:102","message":"StartAsync entry","data":{"baseUrl":"http://localhost:8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4"}
{"id":"log_1766472329009_ws_endpoint","timestamp":1766472329009,"location":"WebSocketTransportClient.cs:112","message":"WebSocket endpoint built","data":{"endpoint":"ws://localhost:8080/hub/plugin"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1"}
{"id":"log_1766472329009_ws_connect_begin","timestamp":1766472329009,"location":"WebSocketTransportClient.cs:226","message":"ConnectAsync begin","data":{"endpoint":"ws://localhost:8080/hub/plugin","keepAliveSeconds":15},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4"}
{"id":"log_1766472333075_ws_connect_fail","timestamp":1766472333075,"location":"WebSocketTransportClient.cs:233","message":"ConnectAsync failed","data":{"endpoint":"ws://localhost:8080/hub/plugin","exception":"Unable to connect to the remote server"},"sessionId":"debug-session","runId":"run1","hypothesisId":"H1,H4,H5"}

[msanatan]

@ChiehHsi333 what do the logs of the MCP server show?

From your logs, nothing is running on that port:

{"id":"log_1766472280919_netstat","timestamp":1766472280919,"location":"ServerManagementService.cs:272","message":"netstat command executed","data":{"success":false,"stdout":"","stderr":"","command":"/c netstat -ano | findstr :8080"},"sessionId":"debug-session","runId":"run1","hypothesisId":"E"}

Did you start a local server via the editor or otherwise? I see this log:

{"id":"log_1766472326120_start_success","timestamp":1766472326120,"location":"ServerManagementService.cs:197","message":"Process start invoked","data":{"fileName":"cmd.exe","arguments":"/c start "MCP Server" cmd.exe /k "C:/Users/Administrator/.local/bin/uv.exe mcp-for-unity --transport http --http-url http://localhost:8080\""},"sessionId":"debug-session","runId":"run1","hypothesisId":"S1"}

[dsarno]

Closing for lack of information and ability to reproduce.