Capabilities and restrictions

Declare only the capabilities your plugin uses. The sandbox client and host both enforce grants, which are confirmed together with the code hash.

Capability	Available services
storage	Plugin-private JSON get/set/delete
settings	Manifest-defined preference get/set
ui	Dialogs, panels, overlays, composer actions, sandbox views, theme snapshots, notices
patcher	Serialized transforms at registered named hooks
messages	Validated embeds in the current channel
styling	Validated, disposable selector rules
inspection	Sanitized element events, optionally intercepting inspected clicks
shortcuts	Host keyboard shortcut registrations
images	Restricted public HTTPS PNG resources
clipboard	User-action-associated text writes
attachments	Posted-file context actions and bounded metadata lookup
external_links	User-authorized public HTTPS browser navigation

Check a grant

if (api.capabilities.has("storage")) {
  const previous = await api.storage.get<string>("last-view");
  api.logger.debug("Stored view available", {
    available: previous !== undefined,
  });
}

A capability check does not replace error handling: the current context, input, resource limits, and instance lifetime can still make an operation fail.

Unavailable privileges

There is no general network API. The current manifest capability enum does not include network. Legacy references to it are not a way to enable arbitrary requests.

Plugins have no Node/Electron APIs, filesystem, parent DOM, top navigation, popups, or remote scripts. Direct fetch/connect is blocked. The supported image service, attachment lookup, and browser navigation each have narrower rules.

Core owns credentials and transport. Handles belong to a plugin instance and cannot be transferred. New privileged operations require a bounded core extension; see extending the SDK.