One foundation. Seven specialized skills.

Nine principles for how an agent should write code: think before coding, push back when warranted, plan inline, simplicity first, surgical changes, goal-driven execution, know when to stop, calibrate confidence, maintain context.

Find the spec before you plan. Extract problem, personas, success criteria, and non-goals. Reconcile spec with architecture. Persona-check the implementation. Keep the PRD honest.

Name the boundary before you cross it. Put code where it belongs by ownership and change cadence. Change contracts carefully. Measure coupling and cohesion. Don't abstract until the pattern is real.

Test behavior, not implementation. Pick the right layer. Mock sparingly, mock honestly. One reason to fail. Cover failure paths. Stay deterministic. Don't chase coverage.

Incremental by default. Write the rollback before the migration. Make schema changes safe, not fast. Feature-flag the cutover. Backfill idempotently. Actually remove the old path.

Reproduce before you reason. Keep symptom, cause, and fix separate. Bisect, don't guess. Don't mask - understand. Suspect your assumptions first. Fix the class, not the instance.

Read intent first, code second. Review in layers, top-down. Label comments by severity. Hunt for what isn't there. Review tests like code. Self-review before submit.

Stop the bleeding before finding the wound. Communicate while working. Don't lose evidence. One change at a time. Hypothesize explicitly. Know when to escalate. Write the postmortem honestly.