Explore, plan, code, PR loop

Separate codebase exploration from implementation, then verify the change and open a reviewable PR.

Engineering Anthropic planning pull-request tests

Use this when implementation risk comes from not understanding the existing system.

Explore the relevant files, commands, docs, and tests without editing.
Write a concrete plan that names files, data flow, risks, and verification.
Implement the plan in the smallest coherent changes.
Run the planned verification.
Fix failures and update the plan if reality changed.
Open a PR with the plan, diff summary, and verification evidence.

Stop when the PR reviewer can understand what changed and how it was proven.