Claude Corner: Blind Agent Edits → Plan Mode Before Disk Changes

• Start Claude Code in plan mode (--permission-mode plan or Shift+Tab) so it explores and proposes without editing until you approve.
• Pin plan as the project default with permissions.defaultMode, then approve into Manual, accept-edits, or auto when the plan is ready.
• Use Desktop's Code-tab mode selector the same way when you are not in the terminal, and treat plan-first as the cheap way to avoid rework loops.

You ask Claude Code to "fix auth," and it starts rewriting three modules before you see the approach. On a shared Team seat that is not just messy git. It is wasted reads, wasted tools, and a second pass when the first direction was wrong. Plan mode flips the order: research and propose first, touch disk only after you say yes.

Why it matters

Anthropic's cost guidance calls out plan mode for complex work because a wrong first direction burns tokens on repair. Plan mode is a permission mode, not an effort dial: Claude can read files, explore read-only, and write a plan, while source edits stay blocked until you approve. That is a different lever from the Claude Code effort-cap Corner, which caps how hard a session thinks. Use plan when the risk is premature edits, and effort caps when the risk is quota burn on already-approved work. The one move: start big changes in plan, review (edit in your editor if needed), then approve into the mode you want for implementation.

How to run plan mode before edits

Plan mode works in Claude Code CLI, JetBrains (same terminal shortcuts), VS Code (mode indicator), and Claude Desktop's Code tab (mode selector beside send). CLI status target: ⏸ plan mode on.

1. 1. For one session: claude --permission-mode plan. Mid-session, press Shift+Tab (or Alt+M on some Windows terminals) until the status bar shows plan mode. For a single prompt without changing the session mode, prefix with /plan.
2. 2. Give a scoped task ("refactor login rate limits; do not touch billing"). Claude explores and writes a plan. It should not edit source while plan mode is active.
3. 3. When the plan appears: keep planning if wrong; approve and manually review each edit; or approve into auto / accept-edits when offered. Press Ctrl+G to open the plan in your default editor before approval.
4. 4. Make plan the default for terminal sessions in a repo with permissions.defaultMode: "plan" in .claude/settings.json. Override one launch with --permission-mode. In Desktop's Code tab, pick Plan from the mode selector (Plan is session-only; other modes can stick per folder).
5. 5. After approval, implement, then /clear before the next unrelated task so planning context does not tax later turns.

# Explore and plan only (no source edits until you approve)
claude --permission-mode plan

# Mid-session: Shift+Tab until status shows "plan mode on"
# Single prompt: /plan redesign the retry queue without touching auth

mkdir -p .claude
cat > .claude/settings.json <<'JSON'
{
  "permissions": {
    "defaultMode": "plan"
  }
}
JSON

# Optional: start in plan, keep bypassPermissions in the Shift+Tab cycle
# for later (isolated containers/VMs only; not a normal laptop)
# claude --permission-mode plan --allow-dangerously-skip-permissions

# After approve choices or Shift+Tab, leave plan mode.
# Desktop Code tab: mode selector next to send.

Gotchas

• Plan mode blocks source edits until you approve. Read-only exploration still runs. With useAutoModeDuringPlan left on (default), the classifier can approve some shell commands during planning; set it false if you want every non-read-only command to prompt.
• Approving a plan exits plan mode into the mode that approve option describes. To plan again, Shift+Tab back or prefix /plan.
• Project defaultMode: "plan" applies to terminal sessions. VS Code uses claudeCode.initialPermissionMode (or the mode indicator) and does not take the starting mode from the project's .claude/settings.json.
• Plan decides when disk changes are allowed. Effort decides how expensive each turn is. Pair them; do not swap them.
• bypassPermissions is for isolated containers/VMs. Prefer normal plan mode on day-to-day machines.

Recommended AI prompt

Copy this paragraph into ChatGPT, Claude, Gemini, Grok, or whatever you use.

Sources: Plan before editing · Permission modes · Manage costs · Interactive mode · Settings reference