Title: WP_CLI::debug()
Published: June 12, 2025
Last modified: May 22, 2026

---

# WP_CLI::debug()

## In this article

 * [Usage](https://make.wordpress.org/cli/handbook/references/internal-api/wp-cli-debug/?output_format=md#usage)
 * [Notes](https://make.wordpress.org/cli/handbook/references/internal-api/wp-cli-debug/?output_format=md#notes)
 * [Related](https://make.wordpress.org/cli/handbook/references/internal-api/wp-cli-debug/?output_format=md#related)

[↑ Back to top](https://make.wordpress.org/cli/handbook/references/internal-api/wp-cli-debug/?output_format=md#wp--skip-link--target)

Display debug message prefixed with "Debug: " when `--debug` is used.

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## 󠀁[Usage](https://make.wordpress.org/cli/handbook/references/internal-api/wp-cli-debug/?output_format=md#usage)󠁿

    ```
    WP_CLI::debug( $message, $group = false )
    ```

 **$message** (string|WP_Error|Exception|Throwable) Message to write to STDERR.
**
$group** (string|bool) Organize debug message to a specific group.Use `false` to
not group the message. **@return** (void)

---

## 󠀁[Notes](https://make.wordpress.org/cli/handbook/references/internal-api/wp-cli-debug/?output_format=md#notes)󠁿

Debug message is written to STDERR, and includes script execution time.

Helpful for optionally showing greater detail when needed. Used throughout
 WP-CLIWP-
CLI WP-CLI is the Command Line Interface for WordPress, used to do administrative
and development tasks in a programmatic way. The project page is [http://wp-cli.org/](http://wp-cli.org/)
[https://make.wordpress.org/cli/](https://make.wordpress.org/cli/) bootstrap process
for easier debugging and profiling.

    ```
    # Called in `WP_CLI\Runner::set_wp_root()`.
    private static function set_wp_root( $path ) {
        define( 'ABSPATH', Utils\trailingslashit( $path ) );
        WP_CLI::debug( 'ABSPATH defined: ' . ABSPATH );
        $_SERVER['DOCUMENT_ROOT'] = realpath( $path );
    }

    # Debug details only appear when `--debug` is used.
    # $ wp --debug
    # [...]
    # Debug: ABSPATH defined: /srv/www/wordpress-develop.dev/src/ (0.225s)
    ```

_Internal APIAPI An API or Application Programming Interface is a software intermediary
that allows programs to interact with each other and share data in limited, clearly
defined ways. documentation is generated from the WP-CLI codebase on every release.
To suggest improvements, please submit a pull request._

---

## 󠀁[Related](https://make.wordpress.org/cli/handbook/references/internal-api/wp-cli-debug/?output_format=md#related)󠁿

 * **[WP_CLI\Utils\format_items()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-utils-format-items/)**–
   Render a collection of items as an ASCII table, JSONJSON JSON, or JavaScript 
   Object Notation, is a minimal, readable format for structuring data. It is used
   primarily to transmit data between a server and web application, as an alternative
   to XML., CSV, YAML, list of ids, or count.
 * **[WP_CLI\Utils\make_progress_bar()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-utils-make-progress-bar/)**–
   Create a progress bar to display percent completion of a given operation.
 * **[WP_CLI::colorize()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-colorize/)**–
   Colorize a string for output.
 * **[WP_CLI::line()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-line/)**–
   Display informational message without prefix, and ignore `–quiet`.
 * **[WP_CLI::log()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-log/)**–
   Display informational message without prefix.
 * **[WP_CLI::success()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-success/)**–
   Display success message prefixed with "Success: ".
 * **[WP_CLI::warning()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-warning/)**–
   Display warning message prefixed with "Warning: ".
 * **[WP_CLI::error()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-error/)**–
   Display error message prefixed with "Error: " and exit script.
 * **[WP_CLI::halt()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-halt/)**–
   Halt script execution with a specific return code.
 * **[WP_CLI::error_multi_line()](https://make.wordpress.org/cli/handbook/internal-api/wp-cli-error-multi-line/)**–
   Display a multi-line error message in a red box. Doesn’t exit script.

First published

June 12, 2025

Last updated

May 22, 2026

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