MCP tools reference

HCTI’s MCP server provides image generation and organization resource management. Connect your assistant using a client setup guide, then approve the permissions needed for your work.

Listed tools describe supported capabilities. Your current connection may not have permission to execute every tool. Plan eligibility also applies.

Screenshots and rendering

These tools require images:create. Rendering uses the organization’s image credits.

Tool	Arguments	Result
`create_image`	`content` with `html`, optional `css`, and render options; optional `include_image_data`	Created image details.
`create_url_image`	`content` with `url` and render options; optional `include_image_data`	Screenshot details.
`create_templated_image`	`template_id`, `template_values`; optional `version`, `include_image_data`	Image created from the selected template.
`create_batch_images`	Top-level `default_options` and `variations`	Batch image results. Check `get_max_batch_size` first.

For example, arguments to create_url_image:

{
  "content": {
    "url": "https://example.com",
    "viewport_width": 1440,
    "viewport_height": 900,
    "device_scale": 1
  },
  "include_image_data": false
}

Use the rendering parameters and the tool’s input schema for supported options. include_image_data defaults to false; enable it for an inline preview when needed. A deferred render URL requires a separate authenticated PUT and must not be treated as an already rendered, readable image. See storage behavior.

When you already know a template ID, pass it directly. Finding a template by name first requires templates:read.

Template management

Tool	Required permission	Arguments and behavior
`create_template`	`templates:create_update`	`content` with template HTML/CSS and options. Returns template creation details.
`update_template`	`templates:create_update`	`template_id` and complete replacement `content`. Replaces the latest version if it has not rendered; otherwise creates a new version.
`list_templates`	`templates:read`	Required `count` (1–100), optional `max_version`. Returns templates with their latest versions and pagination.
`list_template_versions`	`templates:read`	`template_id`, required `count` (1–100), optional `max_version`. Returns paginated template versions.

Template lists use max_version for pagination; use the returned pagination cursor for the next call. This differs from management-resource lists, which use page_start. See templates for template concepts and the Template Editor for visual design.

Usage and limits

Tool	Required permission	Arguments and result
`check_usage`	`usage:read`	No arguments. Returns `images_used`, `images_allowed`, `overages_enabled`, and `next_reset`.
`get_max_batch_size`	`usage:read`	No arguments. Returns the maximum batch size; `0` means the plan does not support batching, so create images individually.

Neither tool renders an image. Their responses differ from REST usage history; see usage.

Proxies

Tool	Required permission	Arguments
`list_proxies`	`proxies:read`	Optional `count`, `page_start`.
`get_proxy`	`proxies:read`	`id`.
`create_proxy`	`proxies:create_update`	`content`.
`update_proxy`	`proxies:create_update`	`id`, complete replacement `content`.
`delete_proxy`	`proxies:delete`	`id`.

See the Proxies API for content fields and response details. Proxy responses include a top-level username (null for no authentication, with an empty string still valid) and omit passwords. To keep a password during update, send authentication with the unchanged username and retain_password: true, omitting the password. Omitting the whole authentication object removes authentication.

Storage destinations

Tool	Required permission	Arguments
`list_storage_destinations`	`storage_destinations:read`	Optional `count`, `page_start`.
`get_storage_destination`	`storage_destinations:read`	`id`.
`create_storage_destination`	`storage_destinations:create_update`	`content`. Tests a bucket write before enabling.
`update_storage_destination`	`storage_destinations:create_update`	`id`, complete replacement `content`. Connection changes or re-enabling trigger a write test.
`delete_storage_destination`	`storage_destinations:delete`	`id`. Deletes configuration and credentials, not bucket objects.
`get_aws_storage_external_id`	`storage_destinations:create_update`	No arguments. Returns `external_id` for the organization’s AWS trust policy.

See the Storage destinations API for provider-specific content and connection-test results. To keep an access-key secret during update, set connection_info.retain_secret_access_key: true, keep the provider and access key ID unchanged, and omit the secret. Otherwise, supply the secret. Secret access keys are never returned.

OG configurations

Tool	Required permission	Arguments
`list_og_configs`	`og_configs:read`	Optional `count`, `page_start`.
`get_og_config`	`og_configs:read`	`id`.
`create_og_config`	`og_configs:create_update`	`content`, including `config_type`.
`update_og_config`	`og_configs:create_update`	`id`, complete replacement `content`, including `config_type`.
`delete_og_config`	`og_configs:delete`	`id`.

See the OG configurations API for screenshot and template request shapes. Use id for management and the returned domain_id in public OG image URLs.

For example, arguments to create_og_config:

{
  "content": {
    "config_type": "html_css",
    "name": "Website screenshots",
    "base_url": "https://example.com",
    "extract_values": false,
    "default_options": { "viewport_width": 1200, "viewport_height": 630 }
  }
}

Management results and pagination

Management tools return structured results with success, item, and error. On success, item contains the resource, list page, or true for deletion. A list page inside item has data and pagination.next_page_start.

Management lists accept count from 1 to 100 (default 10). Pass the returned cursor as page_start until it is null. Proxy, storage, and OG lists include disabled resources. Do not assume a disabled resource can be used for new renders.

Permission and rate-limit failures can be returned directly as MCP tool errors without this structured wrapper. Check the tool’s error status and message before using its result.

Permissions and rate limits

Management reads share 100 requests/minute per resource family and organization; writes share 20 requests/minute. These allowances are shared with REST. get_aws_storage_external_id uses the storage read group while requiring create/update permission. See rate limits.

If a tool reports insufficient permissions, it was not executed. Reconnect and approve the required access before retrying. A token refresh does not add permissions. For rate-limit errors, wait 60 seconds before retrying.

API key management is available through the REST Management API and dashboard, not MCP. MCP also has no tools for deleting images/templates or changing billing, membership, or organization settings. Use the corresponding REST operations or dashboard where available.

Need help?

Talk to a human. Please email us support@htmlcsstoimage.com with any questions and we’ll gladly help you get started.