The native generateContent adapter never runs uncapped: when
model.max_tokens is unset it sends maxOutputTokens=65,535
(GEMINI_DEFAULT_MAX_OUTPUT_TOKENS) because Gemini treats an omitted cap
as a low internal default. The context compressor's trigger is
pct×(window − max_tokens), and constructing it with max_tokens=None
reserved 0 — so on a 128K Gemma window the trigger landed at 98,304
while the real safe input budget was 65,537, and the provider 400'd
before compaction fired.
Live repro (real imports, temp HERMES_HOME, native Gemini base_url,
window=131072, max_tokens unset):
before: compressor.max_tokens=None, threshold_tokens=98304,
wire maxOutputTokens=65535 → trigger ABOVE the safe budget
after: compressor.max_tokens=65535, threshold_tokens=64000 → below it
Scoped to the native Gemini wiring (provider names + native base_url via
is_native_gemini_base_url; the /openai compat endpoint is excluded). The
generic provider-default reservation gap remains tracked in #63839.
Reported by @Artemonim in #57275 (residual claim 4).
7cefa87ea7