Three coupled fixes that surfaced from a single FunctionGemma test
session where the SLM-as-execution-arm assumption broke down and
every subsequent prompt failed with 'session not idle (state: error)'.
(A) [slm].register_as_arm config. The SLM has always been
unconditionally registered as both classifier AND tier-0 execution
arm. Fine for general-purpose models (ministral, qwen3-chat); breaks
for task-specialised models (FunctionGemma emits function-call
syntax instead of prose; embedding models can't generate). New
pointer-bool config: nil/absent preserves the historical default
(true), explicit false makes the SLM classifier-only and the
execution path skips the slm/* arm. Three table tests cover absent
/ explicit-false / explicit-true decode paths.
(B) Session error recovery. After any routing or engine error, the
session moved to StateError and stayed there until restart — every
new user prompt got rejected with 'session not idle (state: error)'.
ResetError() was already wired for the /init retry path, but the
general user-input and slash-command paths didn't call it. Added
ResetError() before every user-initiated Send in the TUI so a fresh
prompt always represents intent-to-retry. The /init internal retry
already had its own ResetError; left alone.
(C) filterFeasible per-arm rejection logging. Today's 'no feasible
arm for task X' error tells you THAT every arm was rejected but
nothing about WHY. Added slog.Debug per rejection (arm, task,
complexity, reason, the specific violated constraint) plus a
summary line when zero arms are feasible at any quality. Visible
with --verbose; quiet otherwise. Surface area expansion only — no
behaviour change for users not chasing a bug.
vikingowl
0d3d190a8b