Plan Mode (experimental)

Plan Mode is a safe, read-only mode for researching and designing complex changes. It prevents modifications while you research, design and plan an implementation strategy.

Note: Plan Mode is currently an experimental feature.

Experimental features are subject to change. To use Plan Mode, enable it via /settings (search for Plan) or add the following to your settings.json:

{
  "experimental": {
    "plan": true
  }
}

Your feedback is invaluable as we refine this feature. If you have ideas, suggestions, or encounter issues:

• Use the /bug command within the CLI to file an issue.
• Open an issue on GitHub.

• Starting in Plan Mode
• How to use Plan Mode
  • Entering Plan Mode
  • The Planning Workflow
  • Exiting Plan Mode
• Tool Restrictions
  • Customizing Planning with Skills
  • Customizing Policies

Starting in Plan Mode

You can configure Gemini CLI to start directly in Plan Mode by default:

1. Type /settings in the CLI.
2. Search for Default Approval Mode.
3. Set the value to Plan.

Other ways to start in Plan Mode:

• CLI Flag: gemini --approval-mode=plan

• Manual Settings: Manually update your settings.json:

  {
    "general": {
      "defaultApprovalMode": "plan"
    }
  }

How to use Plan Mode

Entering Plan Mode

You can enter Plan Mode in three ways:

1. Keyboard Shortcut: Press Shift+Tab to cycle through approval modes (Default -> Plan -> Auto-Edit).
2. Command: Type /plan in the input box.
3. Natural Language: Ask the agent to “start a plan for…”. The agent will then call the enter_plan_mode tool to switch modes.

The Planning Workflow

1. Requirements: The agent clarifies goals using ask_user.
2. Exploration: The agent uses read-only tools (like read_file) to map the codebase and validate assumptions.
3. Design: The agent proposes alternative approaches with a recommended solution for you to choose from.
4. Planning: A detailed plan is written to a temporary Markdown file.
5. Review: You review the plan.
   • Approve: Exit Plan Mode and start implementation (switching to Auto-Edit or Default approval mode).
   • Iterate: Provide feedback to refine the plan.

Exiting Plan Mode

To exit Plan Mode:

1. Keyboard Shortcut: Press Shift+Tab to cycle to the desired mode.
2. Tool: The agent calls the exit_plan_mode tool to present the finalized plan for your approval.

Tool Restrictions

Plan Mode enforces strict safety policies to prevent accidental changes.

These are the only allowed tools:

• FileSystem (Read): read_file, list_directory, glob
• Search: grep_search, google_web_search
• Interaction: ask_user
• MCP Tools (Read): Read-only MCP tools (e.g., github_read_issue, postgres_read_schema) are allowed.
• Planning (Write): write_file and replace ONLY allowed for .md files in the ~/.gemini/tmp/<project>/<session-id>/plans/ directory.
• Skills: activate_skill (allows loading specialized instructions and resources in a read-only manner)

Customizing Planning with Skills

You can leverage Agent Skills to customize how Gemini CLI approaches planning for specific types of tasks. When a skill is activated during Plan Mode, its specialized instructions and procedural workflows will guide the research and design phases.

For example:

• A “Database Migration” skill could ensure the plan includes data safety checks and rollback strategies.
• A “Security Audit” skill could prompt the agent to look for specific vulnerabilities during codebase exploration.
• A “Frontend Design” skill could guide the agent to use specific UI components and accessibility standards in its proposal.

To use a skill in Plan Mode, you can explicitly ask the agent to “use the [skill-name] skill to plan…” or the agent may autonomously activate it based on the task description.

Customizing Policies

Plan Mode is designed to be read-only by default to ensure safety during the research phase. However, you may occasionally need to allow specific tools to assist in your planning.

Because user policies (Tier 2) have a higher base priority than built-in policies (Tier 1), you can override Plan Mode’s default restrictions by creating a rule in your ~/.gemini/policies/ directory.

Example: Allow git status and git diff in Plan Mode

This rule allows you to check the repository status and see changes while in Plan Mode.

~/.gemini/policies/git-research.toml

[[rule]]
toolName = "run_shell_command"
commandPrefix = ["git status", "git diff"]
decision = "allow"
priority = 100
modes = ["plan"]

Example: Enable research sub-agents in Plan Mode

You can enable experimental research sub-agents like codebase_investigator to help gather architecture details during the planning phase.

~/.gemini/policies/research-subagents.toml

[[rule]]
toolName = "codebase_investigator"
decision = "allow"
priority = 100
modes = ["plan"]

Tell the agent it can use these tools in your prompt, for example: “You can check ongoing changes in git.”

For more information on how the policy engine works, see the Policy Engine Guide.