Harden non-success trajectory truncation

README.md

@@ -210,13 +210,21 @@ Training use is tracked separately as `SFT_FULL`, `SFT_STEP_ONLY`,
 
 1. The boundary call receives the trajectory as roughly 32-turn blocks without
    splitting an assistant action from its immediate tool result. It cannot see
-   `resolved`, model patches, or reference patches. It selects the earliest
+   `resolved` or reference patches, but it does see the trajectory's own final
+   model patch to check task coverage and diff pollution. It selects the earliest
    unrepaired major/critical assistant turn, keeps a safe full process trace,
    or returns `HOLD` when neither decision is supported.
 2. Python slices the exact messages before that assistant turn. The quality call
    receives only this materialized prefix, so suffix behavior cannot affect its
    score.
 
+For a complete trajectory, the quality call also sees its final model patch. A
+truncated prefix never receives that suffix-derived patch. Every non-success
+trajectory (`resolved=0` or `-1`) is capped before its first statically detected
+state-changing assistant turn. The effective boundary is the earlier of this
+local cap and the GLM boundary. This intentionally prefers a shorter, safer
+investigation trace.
+
 Successful trajectories skip boundary selection and are scored as complete
 trajectories. The command remains simple: