The previous commit treated a missing miler_status:<id> key as "not available".
In production only 2 of 34 milers have that key at all, so the agent would have
reported "no available rider" for nearly every failure — a confident wrong
answer in the opposite direction from the bug it fixed.
- _miler_presence returns available / unavailable / unknown. No key, an
unparseable value, or an unrecognised status reads as unknown.
- _find_zone prefers a confirmed-available miler, otherwise reports the nearest
unknown-presence one (it may well be assignable), and returns None only when
every nearby candidate is confirmed off duty.
- Facts carry nearest_miler_within_km + nearest_miler_presence; the prompt
states plainly that unknown presence is not evidence of a coverage gap and
should lean to monitor/escalate rather than ops_alert.
- New eval case for riders-nearby-but-no-presence-data; tests for all three
presence states.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012AJLYcbTHCe45fyFnMfEin
Suriyakumarvijayanayagam
5159c8d1a7