# Troubleshoot Agent Canvas and Composer Discovery

Canvas supplies presentation capabilities; Composer stores and enforces workflow configuration. Correct a Composer Config Set when a Blueprint is stale or contradictory. Edit Canvas only when a required template, pattern, token, or other presentation capability is genuinely missing from the theme.

## After installing or updating Canvas

1. Open **SmartCloud → Agent Composer → Theme & providers**.
2. Choose **Rescan site**.
3. Confirm the Canvas name and version, templates, patterns, registered blocks, and presentation manifest.
4. Keep the active Config Set immutable.
5. Clone the active set if discovered capabilities require a change.
6. Correct the working copy, validate it, preview representative page types, and activate the successor explicitly.

A site scan never rewrites or activates a Config Set.

## `Custom HTML blocks cannot be enabled by a Blueprint`

The selected Config Set contains a Blueprint that enables active Custom HTML. Remove `core/html`, set `custom_html` to `false`, disable JavaScript-in-HTML allowances, and clear related Custom HTML extension entries in a cloned or replacement Config Set. Rescanning alone cannot resolve this contradiction.

Passive legacy HTML may be available through a separately constrained Text Editor or `core/freeform` contract. That does not permit scripts, iframes, forms, event-handler attributes, or `javascript:` URLs.

## `INVALID_ARGUMENT` after activating a new contract

Refresh or recreate the client app's scanned actions and begin a new conversation. Validation and draft operations must include the exact BCP 47 `content_language` returned by the selected Blueprint, such as `en-US`. A previously scanned action schema can omit a newly required field even when the WordPress backend and Blueprint are current.

## The client still sees an old Blueprint

Confirm the active Config Set in Composer, restart the site-specific MCP runtime if necessary, refresh the app's action definitions, and start a new client conversation. A long-lived MCP connection can retain configuration or tool-schema state from before the activation.