Implement client-side vapi tool handler

[sahilsuman933]

Description

• Added an example demonstrating client-side tool implementation using the Vapi Web SDK.
• Showcases how to define a tool directly in the vapi.start() configuration without a serverUrl, making it a client-side tool.
• Illustrates how to listen for tool-calls messages via vapi.on('message') to trigger client-side UI updates.
• Emphasizes that client-side tools are for UI side-effects and do not send responses back to the model.
• Includes an example of using vapi.addMessage to inject additional context into the conversation.

Testing Steps

• Run the app locally using fern docs dev or navigate to preview deployment
• Start a call by clicking "Start Call".
• Ask the assistant to update the UI (e.g., "Can you show a message?", "Please refresh the screen").
• Verify that a notification appears at the top of the screen, indicating a UI update.

---

 

[cursor]

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
_{Learn more about Cursor Agents}

[github-actions]

🌿 Preview your docs: https://vapi-preview-f994d1f9-9e17-4193-a1a3-733e41267504.docs.buildwithfern.com