Key points
- Plan mode suits complex work: large-scale changes, several valid approaches, architectural decisions and multi-file edits.
- Direct execution suits simple, well-scoped changes such as one validation check in one function.
- Plan mode prevents costly rework by surfacing dependencies and trade-offs before any code changes.
- The Explore subagent handles verbose discovery and returns a summary, keeping the main conversation's context intact.
- A common pattern is investigation in plan mode followed by implementation in direct execution.
Skills the exam expects
- Pick plan mode for architectural tasks such as service restructuring, migrations touching dozens of files, or choosing between integration approaches.
- Pick direct execution for a single-file fix with a clear stack trace or a small conditional.
- Delegate discovery to the Explore subagent during multi-phase tasks to avoid context exhaustion.
- Combine plan mode and direct execution on one task.
Common misconceptions
- "Plan mode is always safer, so use it for everything." It is overhead on a clear one-line fix.
- "Start executing and plan only if things get complicated." Complexity found mid-implementation is the expensive kind.
- "A detailed enough prompt replaces exploration." It assumes you already know what exploration would reveal.
Watch for
- Starting a multi-file migration file by file without a design.
- Raw discovery output flooding the main session.
- Staying in plan mode after the plan is agreed.
Practice task 3.4
55 practice items cover this task in CCA Prep Studio: flashcards, matching, scenario questions and explain-it-back exercises, each tracked toward your mastery score.