Pull request checks for executable preconditions and postconditions
Teams evaluating coding agents can add executable specification checks to their review path for repository tasks. CodeSpecBench shows why this matters: function-level spec generation reaches 47.0% pass rate, but repository-level performance on 500 SWE-bench Verified issues falls to 20.2% for the best model. The gap points to a concrete failure mode in production code review: an agent may produce a plausible patch without capturing the intended input constraints, state assumptions, or output guarantees.
A practical build is a CI step that asks the model for preconditions and postconditions on the functions touched by a pull request, runs them against existing and generated tests, and flags mismatches for reviewer inspection. This fits teams already using agent-written patches in Python services or libraries, because the output is executable and can be checked with the same test harnesses they trust today. A cheap pilot is a one-week trial on bug-fix PRs in one repository: track how often generated specs fail while the patch still looks acceptable in review, and whether those failures surface hidden semantic regressions earlier than existing tests.