Sandbox

New in v3.7.0. The Sandbox is where code your AI agent generates through the MCP tools actually lives: custom Gutenberg blocks, custom Elementor widgets, and PHP snippets. Everything is isolated under wp-content/emcp-sandbox, never your theme, WordPress core, or another plugin, and every artifact is created inactive. A human has to review and activate it before it runs. That review step is the whole point: the AI never writes raw PHP or JS directly into your site.

EMCP Tools → Sandbox is a three-card overview (Blocks / Widgets / PHP Snippets), each opening its own management screen.

Pillar	Tier	What it is
Blocks	Pro	AI-generated custom Gutenberg blocks, compiled from a spec. Active blocks appear in the block editor inserter under “EMCP Custom.”
Widgets	Pro	AI-generated custom Elementor widgets, sandboxed and shown in the panel under “Custom (EMCP).” Tool reference: Widget Builder.
PHP Snippets	Free (capability-gated)	Small PHP snippets an AI agent can draft, run as a shortcode or on a hook, that stay inactive until reviewed.

This page covers the PHP Snippets tools (undocumented elsewhere) and the admin review workflow shared by all three pillars. For creating custom Elementor widgets, see Widget Builder; for custom Gutenberg blocks, the tool reference is below.

PHP Snippets tools

A snippet runs as a shortcode ([emcp_snippet id="N"]), on a WordPress hook, or both. Code is validated on every create/update and rejected if it trips a critical security finding, the findings come back so the agent can fix it. create-php-snippet always produces an inactive draft; it never runs until an admin activates it in the Sandbox.

Tool	Purpose
emcp-tools/validate-php-snippet	Dry-run validation, no code is saved.
emcp-tools/create-php-snippet	Create a snippet as an inactive draft.
emcp-tools/update-php-snippet	Update code/settings; re-validates. An active snippet is recompiled, or demoted to draft if it no longer passes.
emcp-tools/get-php-snippet	Return a snippet’s code, settings, and status.
emcp-tools/list-php-snippets	List snippets (id, title, status).
emcp-tools/delete-php-snippet	Delete a snippet.

create-php-snippet / update-php-snippet input:

• title — a label for the snippet.
• code (required on create) — PHP code, no <?php tag needed, runs inside an isolated function. Use return or echo for shortcode output.
• context — "shortcode", "hook", or "both". Defaults to shortcode.
• hook — the WordPress action to attach to when context is hook/both (e.g. wp_footer, init).
• priority — hook priority, default 10.

Activation always requires a human, in the Sandbox UI, regardless of who created the draft.

Custom Gutenberg Blocks tools

Same shape as Widget Builder, for the block editor instead of Elementor: the agent submits a JSON spec plus an HTML template with {{control}} placeholders, never raw JS, and the plugin compiles a real block.

Tool	Purpose
emcp-tools/list-block-control-types	List supported attribute types + template syntax, call first.
emcp-tools/validate-block-spec	Dry-run the generator, no code saved.
emcp-tools/create-custom-block	Generate a block as an inactive draft from a spec.
emcp-tools/update-custom-block	Replace a block’s spec, regenerate, re-validate.
emcp-tools/get-custom-block	Return a block’s spec, generated code, and status.
emcp-tools/list-custom-blocks	List generated blocks (id, title, block name, status).
emcp-tools/set-block-status	Activate or deactivate a block.
emcp-tools/delete-custom-block	Delete a block (record + sandbox files).

Template syntax matches the Widget Builder: {{attribute_name}} for values, {{#if name}}…{{/if}} for conditionals, {{#each repeater}}…{{/each}} for loops, every value escaped by its declared attribute type. A runtime safety net isolates compile failures, a malformed block is demoted to draft with a recorded error rather than breaking the block editor.

The Sandbox admin screens

Each pillar’s management screen (Blocks, Widgets, PHP Snippets) shows a table of that pillar’s artifacts with the same core actions:

• Activate / Deactivate — the human review gate. Nothing an agent creates runs until this happens.
• Delete — removes the record and its sandbox files.
• Export — download a .json bundle of the artifact.
• Import a bundle — upload a .json bundle exported from another site (or from Export); imports always land as a new inactive draft.
• View code — inspect the generated PHP/JS before deciding whether to activate it.

Cloud Library and Marketplace

If the EMCP Cloud module is connected, each pillar also gets:

• Save to Cloud — back up an artifact to your EMCP Cloud account.
• Cloud Library — browse and import artifacts you’ve saved from any of your connected sites into the current one, as a new inactive draft to review.
• Publish — publish an artifact to the EMCP Marketplace for others to install.
• Push update — publish a new version of something you already published; artifacts published before update-tracking existed self-heal to offer this on their first push.

These buttons, and the plain Export / Import a bundle buttons above, are calls to MCP tools an agent can also use directly: export-sandbox-artifact / import-sandbox-artifact for the general portable-bundle mechanism (no Cloud connection needed), and cloud-backup / cloud-pull / cloud-marketplace-list / cloud-marketplace-install for the Cloud-connected versions. Full tool reference: EMCP Cloud & Marketplace.

Permissions

Creating, updating, activating, and deleting any Sandbox artifact requires manage_options plus unfiltered_html, the same bar as site-wide custom code. Read/validate tools require edit_posts.