MCP API: sometimes returns "no output" even when output exists

PSU 2026.1.6

MCP output:

2026-06-08 13:46:35.507 [info] [editor -> server] {"jsonrpc":"2.0","id":4,"method":"tools/call","params":{"name":"Get_OS_installation_compliance","arguments":{"Servername":"REDACTED"},"_meta":{"progressToken":"REDACTED","vscode.conversationId":"REDACTED","vscode.requestId":"REDACTED","traceparent":"REDACTED"}}}
2026-06-08 13:47:05.682 [info] [server -> editor] {"result":{"content":[{"type":"text","text":"Job completed successfully with no output."}]},"id":4,"jsonrpc":"2.0"}

PSU job log output:

Get-PSUJobPipelineOutput -RunId 'e8add5e9-5152-4e99-9c9e-391a7682b464' -UseDefaultCredentials -ComputerName 'http://localhost:5075'
{"Message":{"REDACTED"},"Result":1}

Screenshot:

This works in several scripts that are structured the same and in some it doesn't. I can't really see a difference why most scripts/tools would answer fine and some have this problem.

Both functions do something like this to return data
return $ComplianceResult
And in both cases I do something like this to serialize it
Function-Call -Parameters Inputs | ConvertTo-Json -Depth 100 -Compress

Curiously, I get the following error in the Pipeline Output tab. But I don't think it's relevant to this problem, because I get this error in the tools that don't work, but also in the tools that do work: