# Policy engine

Gemini CLI includes a powerful policy engine that provides fine-grained control
over tool execution. It allows users and administrators to define rules that
determine whether a tool call should be allowed, denied, or require user
confirmation.

## Quick start

To create your first policy:

1.  **Create the policy directory** if it doesn't exist:

    **macOS/Linux**

    ```bash
    mkdir -p ~/.gemini/policies
    ```

    **Windows (PowerShell)**

    ```powershell
    New-Item -ItemType Directory -Force -Path "$env:USERPROFILE\.gemini\policies"
    ```

2.  **Create a new policy file** (for example,
    `~/.gemini/policies/my-rules.toml`). You can use any filename ending in
    `.toml`; all such files in this directory will be loaded and combined:
    ```toml
    [[rule]]
    toolName = "run_shell_command"
    commandPrefix = "rm -rf"
    decision = "deny"
    priority = 100
    ```
3.  **Run a command** that triggers the policy (for example, ask Gemini CLI to
    `rm -rf /`). The tool will now be blocked automatically.

## Core concepts

The policy engine operates on a set of rules. Each rule is a combination of
conditions and a resulting decision. When a large language model wants to
execute a tool, the policy engine evaluates all rules to find the
highest-priority rule that matches the tool call.

A rule consists of the following main components:

- **Conditions**: Criteria that a tool call must meet for the rule to apply.
  This can include the tool's name, the arguments provided to it, or the current
  approval mode.
- **Decision**: The action to take if the rule matches (`allow`, `deny`, or
  `ask_user`).
- **Priority**: A number that determines the rule's precedence. Higher numbers
  win.

For example, this rule will ask for user confirmation before executing any `git`
command.

```toml
[[rule]]
toolName = "run_shell_command"
commandPrefix = "git"
decision = "ask_user"
priority = 100
```

### Conditions

Conditions are the criteria that a tool call must meet for a rule to apply. The
primary conditions are the tool's name and its arguments.

#### Tool Name

The `toolName` in the rule must match the name of the tool being called.

- **Wildcards**: You can use wildcards to match multiple tools.
  - `*`: Matches **any tool** (built-in or MCP).
  - `mcp_server_*`: Matches any tool from a specific MCP server.
  - `mcp_*_toolName`: Matches a specific tool name across **all** MCP servers.
  - `mcp_*`: Matches **any tool from any MCP server**.

> **Recommendation:** While FQN wildcards are supported, the recommended
> approach for MCP tools is to use the `mcpName` field in your TOML rules. See
> [Special syntax for MCP tools](#special-syntax-for-mcp-tools).

#### Arguments pattern

If `argsPattern` is specified, the tool's arguments are converted to a stable
JSON string, which is then tested against the provided regular expression. If
the arguments don't match the pattern, the rule does not apply.

#### Execution environment

If `interactive` is specified, the rule will only apply if the CLI's execution
environment matches the specified boolean value:

- `true`: The rule applies only in interactive mode.
- `false`: The rule applies only in non-interactive (headless) mode.

If omitted, the rule applies to both interactive and non-interactive
environments.

### Decisions

There are three possible decisions a rule can enforce:

- `allow`: The tool call is executed automatically without user interaction.
- `deny`: The tool call is blocked and is not executed. For global rules (those
  without an `argsPattern`), tools that are denied are **completely excluded
  from the model's memory**. This means the model will not even see the tool as
  an option, which is more secure and saves context window space.
- `ask_user`: The user is prompted to approve or deny the tool call. (In
  non-interactive mode, this is treated as `deny`.)

<!-- prettier-ignore -->
> [!NOTE]
> The `deny` decision is the recommended way to exclude tools. The
> legacy `tools.exclude` setting in `settings.json` is deprecated in favor of
> policy rules with a `deny` decision.

### Priority system and tiers

The policy engine uses a sophisticated priority system to resolve conflicts when
multiple rules match a single tool call. The core principle is simple: **the
rule with the highest priority wins**.

To provide a clear hierarchy, policies are organized into three tiers. Each tier
has a designated number that forms the base of the final priority calculation.

| Tier      | Base | Description                                                                       |
| :-------- | :--- | :-------------------------------------------------------------------------------- |
| Default   | 1    | Built-in policies that ship with Gemini CLI.                                      |
| Extension | 2    | Policies defined in extensions.                                                   |
| Workspace | 3    | Policies defined in the current workspace's configuration directory.              |
| User      | 4    | Custom policies defined by the user.                                              |
| Admin     | 5    | Policies managed by an administrator (for example, in an enterprise environment). |

Within a TOML policy file, you assign a priority value from **0 to 999**. The
engine transforms this into a final priority using the following formula:

`final_priority = tier_base + (toml_priority / 1000)`

This system guarantees that:

- Admin policies always override User, Workspace, and Default policies (defined
  in policy TOML files).
- User policies override Workspace and Default policies.
- Workspace policies override Default policies.
- You can still order rules within a single tier with fine-grained control.

For example:

- A `priority: 50` rule in a Default policy TOML becomes `1.050`.
- A `priority: 10` rule in a Workspace policy TOML becomes `2.010`.
- A `priority: 100` rule in a User policy TOML becomes `3.100`.
- A `priority: 20` rule in an Admin policy TOML becomes `4.020`.

### Approval modes

Approval modes allow the policy engine to apply different sets of rules based on
the CLI's operational mode. A rule in a TOML policy file can be associated with
one or more modes (for example, `yolo`, `autoEdit`, `plan`). The rule will only
be active if the CLI is running in one of its specified modes. If a rule has no
modes specified, it is always active.

- `default`: The standard interactive mode where most write tools require
  confirmation.
- `autoEdit`: Optimized for automated code editing; some write tools may be
  auto-approved.
- `plan`: A strict, read-only mode for research and design. See
  [Customizing Plan Mode Policies](../cli/plan-mode.md#customizing-policies).
- `yolo`: A mode where all tools are auto-approved (use with extreme caution).

To maintain the integrity of Plan Mode as a safe research environment,
persistent tool approvals are context-aware. When you select **"Allow for all
future sessions"**, the policy engine explicitly includes the current mode and
all more permissive modes in the hierarchy (`plan` < `default` < `autoEdit` <
`yolo`).

- **Approvals in `plan` mode**: These represent an intentional choice to trust a
  tool globally. The resulting rule explicitly includes all modes (`plan`,
  `default`, `autoEdit`, and `yolo`).
- **Approvals in other modes**: These only apply to the current mode and those
  more permissive. For example:
  - An approval granted in **`default`** mode applies to `default`, `autoEdit`,
    and `yolo`.
  - An approval granted in **`autoEdit`** mode applies to `autoEdit` and `yolo`.
  - An approval granted in **`yolo`** mode applies only to `yolo`. This ensures
    that trust flows correctly to more permissive environments while maintaining
    the safety of more restricted modes like `plan`.

## Rule matching

When a tool call is made, the engine checks it against all active rules,
starting from the highest priority. The first rule that matches determines the
outcome.

A rule matches a tool call if all of its conditions are met:

1.  **Tool name**: The `toolName` in the TOML rule must match the name of the
    tool being called.
    - **Wildcards**: You can use wildcards like `*`, `mcp_server_*`, or
      `mcp_*_toolName` to match multiple tools. See [Tool Name](#tool-name) for
      details.
2.  **Arguments pattern**: If `argsPattern` is specified, the tool's arguments
    are converted to a stable JSON string, which is then tested against the
    provided regular expression. If the arguments don't match the pattern, the
    rule does not apply.

## Configuration

Policies are defined in `.toml` files. The CLI loads these files from Default,
User, and (if configured) Admin directories.

### Policy locations

| Tier          | Type   | Location                                  |
| :------------ | :----- | :---------------------------------------- |
| **User**      | Custom | `~/.gemini/policies/*.toml`               |
| **Workspace** | Custom | `$WORKSPACE_ROOT/.gemini/policies/*.toml` |
| **Admin**     | System | _See below (OS specific)_                 |

#### System-wide policies (Admin)

Administrators can enforce system-wide policies (Tier 4) that override all user
and default settings. These policies can be loaded from standard system
locations or supplemental paths.

##### Standard Locations

These are the default paths the CLI searches for admin policies:

| OS          | Policy Directory Path                             |
| :---------- | :------------------------------------------------ |
| **Linux**   | `/etc/gemini-cli/policies`                        |
| **macOS**   | `/Library/Application Support/GeminiCli/policies` |
| **Windows** | `C:\ProgramData\gemini-cli\policies`              |

##### Supplemental Admin Policies

Administrators can also specify supplemental policy paths using:

- The `--admin-policy` command-line flag.
- The `adminPolicyPaths` setting in a system settings file.

These supplemental policies are assigned the same **Admin** tier (Base 4) as
policies in standard locations.

**Security Guard**: Supplemental admin policies are **ignored** if any `.toml`
policy files are found in the standard system location. This prevents flag-based
overrides when a central system policy has already been established.

#### Security Requirements

To prevent privilege escalation, the CLI enforces strict security checks on the
**standard system policy directory**. If checks fail, the policies in that
directory are **ignored**.

- **Linux / macOS:** Must be owned by `root` (UID 0) and NOT writable by group
  or others (for example, `chmod 755`).
- **Windows:** Must be in `C:\ProgramData`. Standard users (`Users`, `Everyone`)
  must NOT have `Write`, `Modify`, or `Full Control` permissions. If you see a
  security warning, use the folder properties to remove write permissions for
  non-admin groups. You may need to "Disable inheritance" in Advanced Security
  Settings.

<!-- prettier-ignore -->
> [!NOTE]
> Supplemental admin policies (provided via `--admin-policy` or
> `adminPolicyPaths` settings) are **NOT** subject to these strict ownership
> checks, as they are explicitly provided by the user or administrator in their
> current execution context.

### TOML rule schema

Here is a breakdown of the fields available in a TOML policy rule:

```toml
[[rule]]
# A unique name for the tool, or an array of names.
toolName = "run_shell_command"

# (Optional) The name of a subagent. If provided, the rule only applies to tool
# calls made by this specific subagent.
subagent = "codebase_investigator"

# (Optional) The name of an MCP server. Can be combined with toolName
# to form a composite FQN internally like "mcp_mcpName_toolName".
mcpName = "my-custom-server"

# (Optional) Metadata hints provided by the tool. A rule matches if all
# key-value pairs provided here are present in the tool's annotations.
toolAnnotations = { readOnlyHint = true }

# (Optional) A regex to match against the tool's arguments.
argsPattern = '"command":"(git|npm)'

# (Optional) A string or array of strings that a shell command must start with.
# This is syntactic sugar for `toolName = "run_shell_command"` and an
# `argsPattern`.
commandPrefix = "git"

# (Optional) A regex to match against the entire shell command.
# This is also syntactic sugar for `toolName = "run_shell_command"`.
# Note: This pattern is tested against the JSON representation of the arguments
# (e.g., `{"command":"<your_command>"}`). Because it prepends `"command":"`,
# it effectively matches from the start of the command.
# Anchors like `^` or `$` apply to the full JSON string,
# so `^` should usually be avoided here.
# You cannot use commandPrefix and commandRegex in the same rule.
commandRegex = "git (commit|push)"

# The decision to take. Must be "allow", "deny", or "ask_user".
decision = "ask_user"

# The priority of the rule, from 0 to 999.
priority = 10

# (Optional) A custom message to display when a tool call is denied by this
# rule. This message is returned to the model and user,
# useful for explaining *why* it was denied.
denyMessage = "Deletion is permanent"

# (Optional) An array of approval modes where this rule is active.
# If omitted or empty, the rule applies to all modes.
modes = ["default", "autoEdit", "yolo"]

# (Optional) A boolean to restrict the rule to interactive (true) or
# non-interactive (false) environments.
# If omitted, the rule applies to both.
interactive = true

# (Optional) If true, lets shell commands use redirection operators
# (>, >>, <, <<, <<<). By default, the policy engine asks for confirmation
# when redirection is detected, even if a rule matches the command.
# This permission is granular; it only applies to the specific rule it's
# defined in. In chained commands (e.g., cmd1 > file && cmd2), each
# individual command rule must permit redirection if it's used.
allowRedirection = true
```

### Using arrays (lists)

To apply the same rule to multiple tools or command prefixes, you can provide an
array of strings for the `toolName` and `commandPrefix` fields.

**Example:**

This single rule will apply to both the `write_file` and `replace` tools.

```toml
[[rule]]
toolName = ["write_file", "replace"]
decision = "ask_user"
priority = 10
```

### Special syntax for `run_shell_command`

To simplify writing policies for `run_shell_command`, you can use
`commandPrefix` or `commandRegex` instead of the more complex `argsPattern`.

- `commandPrefix`: Matches if the `command` argument starts with the given
  string.
- `commandRegex`: Matches if the `command` argument matches the given regular
  expression.

**Example:**

This rule will ask for user confirmation before executing any `git` command.

```toml
[[rule]]
toolName = "run_shell_command"
commandPrefix = "git"
decision = "ask_user"
priority = 100
```

### Special syntax for MCP tools

You can create rules that target tools from Model Context Protocol (MCP) servers
using the `mcpName` field. **This is the recommended approach** for defining MCP
policies, as it is much more robust than manually writing Fully Qualified Names
(FQNs) or string wildcards.

<!-- prettier-ignore -->
> [!WARNING]
> Do not use underscores (`_`) in your MCP server names (for example, use
> `my-server` rather than `my_server`). The policy parser splits Fully Qualified
> Names (`mcp_server_tool`) on the _first_ underscore following the `mcp_`
> prefix. If your server name contains an underscore, the parser will
> misinterpret the server identity, which can cause wildcard rules and security
> policies to fail silently.

**1. Targeting a specific tool on a server**

Combine `mcpName` and `toolName` to target a single operation. When using
`mcpName`, the `toolName` field should strictly be the simple name of the tool
(for example, `search`), **not** the Fully Qualified Name (for example,
`mcp_server_search`).

```toml
# Allows the `search` tool on the `my-jira-server` MCP
[[rule]]
mcpName = "my-jira-server"
toolName = "search"
decision = "allow"
priority = 200
```

**2. Targeting all tools on a specific server**

Specify only the `mcpName` to apply a rule to every tool provided by that
server.

**Note:** This applies to all decision types (`allow`, `deny`, `ask_user`).

```toml
# Denies all tools from the `untrusted-server` MCP
[[rule]]
mcpName = "untrusted-server"
decision = "deny"
priority = 500
denyMessage = "This server is not trusted by the admin."
```

**3. Targeting all MCP servers**

Use `mcpName = "*"` to create a rule that applies to **all** tools from **any**
registered MCP server. This is useful for setting category-wide defaults.

```toml
# Ask user for any tool call from any MCP server
[[rule]]
toolName = "*"
mcpName = "*"
decision = "ask_user"
priority = 10
```

### Special syntax for subagents

You can secure and govern subagents using standard policy rules by treating the
subagent's name as the `toolName`.

When the main agent invokes a subagent (e.g., using the unified `invoke_agent`
tool), the Policy Engine automatically treats the target `agent_name` as a
virtual tool alias for rule matching.

**Example:**

This rule denies access to the `codebase_investigator` subagent.

```toml
[[rule]]
toolName = "codebase_investigator"
decision = "deny"
priority = 500
deny_message = "Deep codebase analysis is restricted for this session."
```

- **Backward Compatibility**: Any rules written targeting historical 1:1
  subagent tool names will continue to match transparently.
- **Context differentiation**: To create rules based on **who** is calling a
  tool, use the `subagent` field instead. See
  [TOML rule schema](#toml-rule-schema).

## Context-Aware Security (Conseca)

Context-Aware Security (Conseca) is an experimental feature that uses an LLM to
dynamically evaluate tool calls based on the intent of your prompt. It provides
an additional layer of protection by identifying potentially harmful actions
that might otherwise match an "allow" rule.

### How it works

When Conseca is enabled, every tool call that would be automatically allowed is
first sent to a security classifier. The classifier analyzes the tool call, its
arguments, and the original user prompt to determine if the action is safe and
aligned with the user's intent.

If the classifier identifies a potential security risk, it can override an
`allow` decision and force it to `ask_user` or `deny`.

### Enable Conseca

To enable Conseca, set the `security.enableConseca` setting to `true`.

```bash
gemini config set security.enableConseca true
```

<!-- prettier-ignore -->
> [!NOTE]
> Conseca is an experimental feature and may increase the latency of tool
> execution, as it requires an additional model call for security validation.

## Default policies

Gemini CLI ships with a set of default policies to provide a safe out-of-the-box
experience.

- **Read-only tools** (like `read_file`, `glob`) are generally **allowed**.
- **Agent delegation** defaults to **`ask_user`** to ensure remote agents can
  prompt for confirmation, but local sub-agent actions are executed silently and
  checked individually.
- **Write tools** (like `write_file`, `run_shell_command`) default to
  **`ask_user`**.
- In **`yolo`** mode, a high-priority rule allows all tools.
- In **`autoEdit`** mode, rules allow certain write operations to happen without
  prompting.