Give your voice AI agent real abilities (tool calling)

Code for this episode → https://g.dev/cloud/voicedemo1 Gemini Live API docs → https://g.dev/cloud/gemini-live Agent Development Kit (ADK) docs → https://g.dev/cloud/adk-docs Tool calling for real-time voice AI agents, not the request-response version you've seen a hundred times. The agent acts mid-conversation and the conversation doesn't break. Three parts: - The loop (declare, decide, execute, return, the model decides, your code acts) - The same ability written two ways (a raw google-genai dict vs a plain Python function with a docstring in Google ADK) -And the two rules that decide whether a live agent feels alive or broken, keep every tool instant, and put your policy in one before_tool_callback. There's a checkpoint before execution. In ADK it's before_tool_callback, and it sees every tool call before the tool runs. The demo is a quiet-hours rule: the model tries to play something loud, the callback catches it, the playlist never runs, and the agent still responds in character. Chapters: 0:00 - Demo: an agent that acts mid-conversation 0:27 - What you'll learn (three parts) 0:55 - Why the model can only produce words 1:13 - A menu of abilities: name, description, when to use it 1:34 - The loop: declare, decide, execute, return 2:17 - Wrong tool called? Fix the description 2:46 - The raw SDK way: a dict and four arrows you wire 3:07 - The ADK way: a function with a docstring 3:41 - Adding a new ability: set_sleep_timer 4:00 - Demo: the new ability, live 4:18 - Who updates the UI: backend events to the browser 4:56 - Rule 1: tools are synchronous 5:54 - Rule 2: before_tool_callback 6:55 - Demo: the guardrail fires mid-conversation 7:18 - Why this matters when the agent gets a browser 7:51 - Recap: the loop, two ways, two rules 8:29 - Next: controlling a real browser by voice More resources: Roadmap preview → https://g.dev/cloud/mma-roadmap Last episode was Google ADK running the live loop. Next episode the agent controls a real browser, it clicks, it types, it waits for pages to load — which is where this checkpoint stops being optional. → https://g.dev/cloud/real-time-voice-agent Follow Annie online: LinkedIn → https://goo.gle/annie-linkedin X → https://goo.gle/annie-x Watch more The Omni App → https://g.dev/cloud/modern-ai-app 🔔 Subscribe to Google Cloud Tech → https://goo.gle/GoogleCloudTech #GeminiLiveAPI #VoiceAI #AIAgents #MULTIMODAL Speaker: Annie Wang Products Mentioned: Gemini Live API, Agent Development Kit