## What changed
Add `McpBinding` APIs to discover the model's Search tool profile through an already authorized, host-owned Apps connection. Discovery sends turn metadata, paginates `tools/list`, and returns a scoped binding with the refreshed declaration and connector-provided invocation context.
Require a visible Search tool and an object-valued invocation context. Preserve the context only for calls using the same client, while allowing normal dispatch to recheck visibility, account selection, and approval policy.
Bound discovery to five seconds and distinguish critical timeout, transport, and server errors from unavailability. Expose the existing retryable transport error classifier for this distinction.
## Testing
Add coverage for opaque invocation context extraction and extend transport error classification coverage to HTTP 503 and 403 responses, exercising the exported classifier through a contextual error.
GitOrigin-RevId: 9848d4adb91e3fb2b9406349c31d1fd5c5c47a33
yitaoh-oai
3c074bb44a