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Web tools
MiniUp adds a small platform script when delivering an enabled app’s HTML. It does not edit stored files or revisions. No script is added to CSS, images, or other assets.
In a compatible browser the script requests a same-origin manifest, then registers the permitted actions through document.modelContext.registerTool. Execution goes back to a same-origin MiniUp endpoint that rechecks the site, session, permissions, action configuration, and current input schema.
Without WebMCP support the script does nothing and the app behaves normally. Browser and agent support vary; enabling the feature does not guarantee a particular browser exposes tools to its AI assistant.
The bootstrap works on MiniUp app subdomains and active custom domains using trusted host resolution. It does not expose actions from inaccessible cross-origin frames. Registration uses exposedTo: []; outputs are marked untrusted. Read-only and consequential hints reflect the action’s risk. An ordinary write is not automatically marked consequential.
Registration refreshes on page show and focus. Server checks still enforce changes immediately. The delivery bootstrap’s configuration cache lasts at most 15 seconds. An owner-supplied CSP that blocks the script is respected; MiniUp does not relax CSP to enable actions.
Cancellation is forwarded to the action request. Cancellation cannot roll back an operation that has already committed. Do not automatically retry mutations after a timeout or ambiguous network error.
The implementation follows the 17 September 2026 WebMCP draft , including its tools Permissions Policy and untrusted/consequential annotations.