Plan Mode for Complex Work

When to Use Plan Mode

Plan mode is for any task that has 3+ steps, involves architectural decisions, or spans multiple files/systems. Jumping straight to implementation on complex work produces messy results.

Trigger plan mode by prepending your request with:

"Plan: Build a real-time notification system..."

Or use the /plan command.

The Planning Cycle

Plan mode produces:

1. Spec — what are we building and why
2. Architecture — how it fits into the existing system
3. Task list — ordered, dependency-aware steps
4. Risks — what could go wrong

Review the plan before approving execution. Push back on ambitious plans — ship small wins.

Evals Before Specs

Before writing a spec, define success criteria:

• What does "done" look like?
• What does "broken" look like?
• What edge cases must work?

This prevents building the wrong thing correctly. Use the evals-before-specs skill to structure this process.

Spec-Based Development for Multi-Day Work

For features taking more than one day:

1. Spend a session writing the spec (with the spec-interviewer skill)
2. Save the spec to tasks/spec-YYYYMMDD.md
3. Start a fresh session and execute from the spec

Fresh context + clear spec = cleaner implementation than continuing a stale session.

The Dialectic Review

For expensive-to-reverse decisions (architecture, vendor choice, data model), spawn a FOR agent and an AGAINST agent, then have a Referee synthesize. This surfaces blind spots before you're committed.

Use the dialectic-review skill for any choice where you catch yourself saying "I'm not sure."