The auxiliary-compression feasibility warning computes its
compression.threshold suggestion as aux_context / main_context,
independently of ContextCompressor._effective_threshold_percent()'s
raise-only small-context floor. For main windows under 512K the floor
raises any configured value below 75% back up, so a suggestion like
'threshold: 0.40' is silently ignored and the same warning returns every
session.
Derive the suggestion's viability through the compressor's own floor
logic: offer the 'lower the threshold' option only when the floored value
still fits the auxiliary model's context; otherwise recommend only a
larger compression model and explain the floor, so the guidance is always
actionable.
Tests: the updated auto-correct test pins the floored branch (no
threshold suggestion, floor explained); two new tests pin the surviving
suggestion at/above the floor on a small window and below 75% on a
512K+ window where no floor applies. The updated test fails against the
previous code.
Fixes#67422
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Sora-bluesky
dbc71fb6e4