The scheduled-research task reads research_max_tokens,
research_extraction_timeout_seconds, and research_extraction_concurrency
with bare int() casts and no guard. A hand-edited or agent-written
data/settings.json value like {"research_max_tokens": "invalid"} raised
ValueError and killed every scheduled research run until settings.json was
fixed by hand (#5049). src/research_handler.py already guards the same reads
defensively (_bounded_int); this mirrors that for the scheduler.
Wrap the three reads in try/except (TypeError, ValueError) falling back to
the documented defaults 8192 / 90 / 3. Valid values (numeric strings like
"4096") still parse; the change is limited to the scheduler's reads (agent_loop
sites are tracked separately in #5051).
Child of maintainer subtracker #5335 (RaresKeY) whose acceptance criteria state:
"Non-numeric agent/scheduler settings fall back safely instead of crashing or
silently degrading." Prior PR #5050 attempted the same fix but was closed
unmerged in the 2026-07-23 repo-transfer bulk close and never resubmitted —
redoing it with credit.
Fixes#5049.
