# FrontierCode

Cognition built FrontierCode 1.1 with maintainers of 36 open source repositories, asking agents to change real repositories and judging whether a maintainer would merge the change. Grading goes beyond passing tests to cover excessive changes, edits outside the relevant scope, and unhelpful tests. Artificial Analysis runs the 100-task Main set in one shared Stirrup harness with three attempts per task; Claude Opus 5.5 leads at 52% average score and 58% pass rate, yet leading models still fail more than 40% of attempts.

Cognition built FrontierCode 1.1 with maintainers of 36 open source repositories, asking agents to change real repositories and judging whether a maintainer would merge the change. Grading goes beyond passing tests to cover excessive changes, edits outside the relevant scope, and unhelpful tests. Artificial Analysis runs the 100-task Main set in one shared Stirrup harness with three attempts per task; Claude Opus 5.5 leads at 52% average score and 58% pass rate, yet leading models still fail more than 40% of attempts.