MGS9027: internal failure
The server answered 500 internal because a step it owns failed after the
request was accepted.
[MGS9027] target graph failed
see: .../MGS9027.md
Why
The message names the step (attention, target graph, graph build,
render, a diff read) and nothing else. The underlying error can carry the
server's absolute paths, so it goes to the server log and never to the client.
Resolution
Read the server's log output for the line with the same step name and the request path. A failure that repeats for every request usually means the workspace state on disk is unreadable; fix that and retry.