A single-slot local server (LM Studio, Ollama) returns 500 "Context size has been exceeded."
when ANOTHER request — a background review from an earlier session — holds its context.
The foreground loop classified that as context_overflow, tried to compress a one-sentence
conversation, could not shrink it, and rendered "This conversation has grown too long …
/new … /compress" with compression_exhausted=True (gateway auto-reset, user message dropped
from the transcript).
_recover_context_length now measures first: when the server quoted no count of its own and
the local request estimate (+ output reservation) sits under half the known window, the turn
ends with distinct copy naming the likely cause (another request on the server / smaller
server window), failure_reason=server_error, retryable, no compression_exhausted — so CLI,
TUI/Desktop and the gateway all render a transient failure. Servers that quote their own
measurement ("233153 tokens > 200000 maximum") and requests near the window keep the
compress-and-retry path unchanged. The two buffered "keeping context_length … and
compressing" notices drop the trailing clause so they read true on both paths.
Fixes#114644
5e95050608