# Plan Mode (experimental)

Plan Mode is a read-only environment for architecting robust solutions before
implementation. It allows you to:

- **Research:** Explore the project in a read-only state to prevent accidental
  changes.
- **Design:** Understand problems, evaluate trade-offs, and choose a solution.
- **Plan:** Align on an execution strategy before any code is modified.

> **Note:** This is a preview feature currently under active development. Your
> feedback is invaluable as we refine this feature. If you have ideas,
> suggestions, or encounter issues:
>
> - [Open an issue](https://github.com/google-gemini/gemini-cli/issues) on
>   GitHub.
> - Use the **/bug** command within Gemini CLI to file an issue.

- [Enabling Plan Mode](#enabling-plan-mode)
- [How to use Plan Mode](#how-to-use-plan-mode)
  - [Entering Plan Mode](#entering-plan-mode)
  - [Planning Workflow](#planning-workflow)
  - [Exiting Plan Mode](#exiting-plan-mode)
- [Tool Restrictions](#tool-restrictions)
  - [Customizing Planning with Skills](#customizing-planning-with-skills)
  - [Customizing Policies](#customizing-policies)
    - [Example: Allow git commands in Plan Mode](#example-allow-git-commands-in-plan-mode)
    - [Example: Enable research subagents in Plan Mode](#example-enable-research-subagents-in-plan-mode)
  - [Custom Plan Directory and Policies](#custom-plan-directory-and-policies)
- [Automatic Model Routing](#automatic-model-routing)

## Enabling Plan Mode

To use Plan Mode, enable it via **/settings** (search for **Plan**) or add the
following to your `settings.json`:

```json
{
  "experimental": {
    "plan": true
  }
}
```

## How to use Plan Mode

### Entering Plan Mode

You can configure Gemini CLI to start in Plan Mode by default or enter it
manually during a session.

- **Configuration:** 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**.

  Alternatively, use the `gemini --approval-mode=plan` CLI flag or manually
  update:

  ```json
  {
    "general": {
      "defaultApprovalMode": "plan"
    }
  }
  ```

- **Keyboard Shortcut:** Press `Shift+Tab` to cycle through approval modes
  (`Default` -> `Auto-Edit` -> `Plan`).

  > **Note:** Plan Mode is automatically removed from the rotation when Gemini
  > CLI is actively processing or showing confirmation dialogs.

- **Command:** Type `/plan` in the input box.

- **Natural Language:** Ask Gemini CLI to "start a plan for...". Gemini CLI then
  calls the [`enter_plan_mode`] tool to switch modes.
  > **Note:** This tool is not available when Gemini CLI is in [YOLO mode].

### Planning Workflow

1.  **Explore & Analyze:** Analyze requirements and use read-only tools to map
    the codebase and validate assumptions. For complex tasks, identify at least
    two viable implementation approaches.
2.  **Consult:** Present a summary of the identified approaches via [`ask_user`]
    to obtain a selection. For simple or canonical tasks, this step may be
    skipped.
3.  **Draft:** Once an approach is selected, write a detailed implementation
    plan to the plans directory.
4.  **Review & Approval:** Use the [`exit_plan_mode`] tool to present the plan
    and formally request approval.
    - **Approve:** Exit Plan Mode and start implementation.
    - **Iterate:** Provide feedback to refine the plan.

For more complex or specialized planning tasks, you can
[customize the planning workflow with skills](#customizing-planning-with-skills).

### Exiting Plan Mode

To exit Plan Mode, you can:

- **Keyboard Shortcut:** Press `Shift+Tab` to cycle to the desired mode.

- **Tool:** Gemini CLI 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 or your
  [custom plans directory](#custom-plan-directory-and-policies).
- **Skills:** [`activate_skill`] (allows loading specialized instructions and
  resources in a read-only manner)

### Customizing Planning with Skills

You can use [Agent Skills](./skills.md) 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, design and planning phases.

For example:

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

To use a skill in Plan Mode, you can explicitly ask Gemini CLI to "use the
`<skill-name>` skill to plan..." or Gemini CLI may autonomously activate it
based on the task description.

### Customizing Policies

Plan Mode's default tool restrictions are managed by the [policy engine] and
defined in the built-in [`plan.toml`] file. The built-in policy (Tier 1)
enforces the read-only state, but you can customize these rules by creating your
own policies in your `~/.gemini/policies/` directory (Tier 2).

#### Example: Automatically approve read-only MCP tools

By default, read-only MCP tools require user confirmation in Plan Mode. You can
use `toolAnnotations` and the `mcpName` wildcard to customize this behavior for
your specific environment.

`~/.gemini/policies/mcp-read-only.toml`

```toml
[[rule]]
mcpName = "*"
toolAnnotations = { readOnlyHint = true }
decision = "allow"
priority = 100
modes = ["plan"]
```

#### Example: Allow git commands in Plan Mode

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

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

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

#### Example: Enable research subagents in Plan Mode

You can enable experimental research [subagents] like `codebase_investigator` to
help gather architecture details during the planning phase.

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

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

Tell Gemini CLI 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]
docs.

### Custom Plan Directory and Policies

By default, planning artifacts are stored in a managed temporary directory
outside your project: `~/.gemini/tmp/<project>/<session-id>/plans/`.

You can configure a custom directory for plans in your `settings.json`. For
example, to store plans in a `.gemini/plans` directory within your project:

```json
{
  "general": {
    "plan": {
      "directory": ".gemini/plans"
    }
  }
}
```

To maintain the safety of Plan Mode, user-configured paths for the plans
directory are restricted to the project root. This ensures that custom planning
locations defined within a project's workspace cannot be used to escape and
overwrite sensitive files elsewhere. Any user-configured directory must reside
within the project boundary.

Using a custom directory requires updating your [policy engine] configurations
to allow `write_file` and `replace` in that specific location. For example, to
allow writing to the `.gemini/plans` directory within your project, create a
policy file at `~/.gemini/policies/plan-custom-directory.toml`:

```toml
[[rule]]
toolName = ["write_file", "replace"]
decision = "allow"
priority = 100
modes = ["plan"]
# Adjust the pattern to match your custom directory.
# This example matches any .md file in a .gemini/plans directory within the project.
argsPattern = "\"file_path\":\"[^\"]+[\\\\/]+\\.gemini[\\\\/]+plans[\\\\/]+[\\w-]+\\.md\""
```

## Automatic Model Routing

When using an [**auto model**], Gemini CLI automatically optimizes [**model
routing**] based on the current phase of your task:

1.  **Planning Phase:** While in Plan Mode, the CLI routes requests to a
    high-reasoning **Pro** model to ensure robust architectural decisions and
    high-quality plans.
2.  **Implementation Phase:** Once a plan is approved and you exit Plan Mode,
    the CLI detects the existence of the approved plan and automatically
    switches to a high-speed **Flash** model. This provides a faster, more
    responsive experience during the implementation of the plan.

This behavior is enabled by default to provide the best balance of quality and
performance. You can disable this automatic switching in your settings:

```json
{
  "general": {
    "plan": {
      "modelRouting": false
    }
  }
}
```

[`list_directory`]: /docs/tools/file-system.md#1-list_directory-readfolder
[`read_file`]: /docs/tools/file-system.md#2-read_file-readfile
[`grep_search`]: /docs/tools/file-system.md#5-grep_search-searchtext
[`write_file`]: /docs/tools/file-system.md#3-write_file-writefile
[`glob`]: /docs/tools/file-system.md#4-glob-findfiles
[`google_web_search`]: /docs/tools/web-search.md
[`replace`]: /docs/tools/file-system.md#6-replace-edit
[MCP tools]: /docs/tools/mcp-server.md
[`activate_skill`]: /docs/cli/skills.md
[subagents]: /docs/core/subagents.md
[policy engine]: /docs/reference/policy-engine.md
[`enter_plan_mode`]: /docs/tools/planning.md#1-enter_plan_mode-enterplanmode
[`exit_plan_mode`]: /docs/tools/planning.md#2-exit_plan_mode-exitplanmode
[`ask_user`]: /docs/tools/ask-user.md
[YOLO mode]: /docs/reference/configuration.md#command-line-arguments
[`plan.toml`]:
  https://github.com/google-gemini/gemini-cli/blob/main/packages/core/src/policy/policies/plan.toml
[auto model]: /docs/reference/configuration.md#model-settings
[model routing]: /docs/cli/telemetry.md#model-routing
