Planner Agents

The planner is the most under-appreciated role. Its only job is to convert an ambiguous task into a concrete plan with file-level changes, a test strategy, and an estimate. Good planners read the codebase first; bad planners hallucinate based on the issue title alone.

System prompts for planners should over-index on "read first, propose second." The bias to action that helps builders is poison for planners. A planner that proposes without reading the relevant files is producing fiction.