Angular had no counterpart to `useComponent` in react-core and vue, so the only
way to let an agent display one of your components was `registerFrontendTool`
with a handler the component does not need, or `registerRenderToolCall`, which
requires the tool to already exist in the agent.
`FrontendToolConfig.handler` becomes optional, and `#bindClientTool` returns the
config unwrapped when it is absent. Core already has the render-only path: a tool
declaring no handler gets an empty tool result and completes the turn. Binding a
wrapper regardless called `undefined` on the first tool call, and a stub handler
would write a fabricated result into the thread instead.
`registerComponent` is that shape with the model-facing description built for it,
identical to the one react-core and vue build, so the tool reads the same to the
model whichever frontend registered the component. The component stays an
ordinary `ToolRenderer` reading `toolCall().args`.
The tool is declared by the frontend and forwarded over AG-UI, so a display-only
component needs nothing added to the agent, on any framework.
Refs OSS-1034
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Benjamin Taylor