Implement Plan Phase

Overview

Read a plan file generated by prd-to-plan, determine the next phase that should be implemented, verify that the recorded plan state still matches the codebase, then implement the next slice and update the plan as work lands.

Keep the workflow conservative around plan drift: when the plan and the code disagree about what is already done, summarize the mismatch and ask the user how to proceed instead of silently rewriting history.

Inputs

Require a concrete plan file path or enough context to identify a single plan file.

Prefer plan files in ./plans/. If the user does not specify a path, search ./plans/ first and infer the most likely file from the request. If multiple candidates fit, ask the user to choose.

Treat the prd-to-plan template as the default structure: