An MCP App (e.g. NightRider's drum-pad) failed to load with
"'[object Object]' is not a spec notification method; pass schemas as the
second argument to setNotificationHandler()". `@modelcontextprotocol/ext-apps`
still peers on SDK v1 and, during the AppBridge connect handshake, subscribes
to tools/resources/prompts list_changed with the v1 schema-first API
`setNotificationHandler(NotificationSchema, handler)`. SDK v2 requires a method
STRING and throws on a schema object — the migration's compat shim covered the
types but not this runtime API difference.
Fix in the app-renderer client Proxy (`getAppRendererClient`): translate a
schema-first `setNotificationHandler` call to v2's method-string form by reading
the method literal off the schema's `shape.method.value`; native string-first
calls pass through, and an unrecognized first arg falls through to the SDK's
clear error rather than being swallowed. Only `setNotificationHandler` needed
this — AppBridge's `request(req, schema, …)` calls work as-is (the v1 SDK
schemas expose `~standard`, so v2 accepts them). Remove when ext-apps#702 ships
a v2 peer.
Added an integration test covering the schema-first translation end-to-end
(handler fires on a real tools/list_changed), plus the string-passthrough and
unrecognized-schema branches. Coverage ≥90 holds; typecheck + App tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
8a7a38f800