[lamestllama]

A language reader, lexer or formatting hook that prints to stdout can interleave plain text with Content-Length frames and corrupt the LSP connection.

Discard callback stdout during request dispatch and scheduled work. The separate response writer retains the protocol output port, and stderr is preserved. Both scopes are needed because the scheduler thread exists before request dispatch establishes its output scope.

A server-subprocess regression exercises a noisy reader through initialization, document open and edit, semantic-token requests, diagnostics, formatting and shutdown. It requires exact protocol framing, useful token/formatting results, and preserved reader stderr. Negative controls fail on contaminated protocol headers when either output scope is removed.

Validation: 431 local tests passed on Racket 9.1 CS/Linux ARM64; formatting checked with fixw. Optional fmt, Resyntax, Nanopass and Pie integrations were unavailable locally and remain covered by CI.