Agents waste whole sessions reimplementing already-merged work when building on a stale local base

A coding agent reimplemented an entire feature (recognition lift, gate wiring, edge provenance, schema constraints, a parity harness) that was ALREADY merged on the team's integration branch via a recently-landed PR. Root cause: the local checkout's base branch was dozens of commits behind origin, and the planning/tracker docs the agent read described the work as "to do" while origin already had it done. The agent trusted the local tracker markdown as ground truth instead of checking origin. The whole effort had to be closed; only one small genuinely-novel piece survived.

This is a general agent failure mode: [REDACTED], and a local checkout can be arbitrarily stale.