[GDG London] A Tale of Three Agents

Talk presented at the GDG London Meetup on September 30th 2026

1. A Tale of Three Agents: Building Agents in Go Daniela Petruzalek Developer Relations Engineer Google Cloud 2026
2. Who am I? Brazilian 󰎙 living in London 󰏅 since 2019 Specialisation: backend (python & Go), data engineering and agentic AI Hobbies: anime, games e cosplay Blog: danicat.dev LinkedIn: linkedin.com/in/petruzalek Twitter: x.com/danicat83 Google Cloud 02
3. Agenda Introduction Agents the hard way (GenAI SDK) Genkit Agent Development Kit (ADK) Google Cloud 03
4. What is an agent?
5. www.merriam-webster.com/dictionary/agent Google Cloud 05
6. www.merriam-webster.com/dictionary/agency Google Cloud 06
7. AI Agents Software systems that use AI to perform tasks e achieve objectives on behalf of its users. Basically: a model with access to tools (functions) that allow it to interact with the external world Google Cloud 07
8. The agent My objective: stop buying the same game twice Google Cloud 08
9. User Agent Tools Model Should I buy Puyo Puyo Tsu (PS2) for £15? user prompt + system prompt + tools Tool call request: query_database("puyo puyo") query_database("puyo puyo") { "found": ["puyo puyo tsu (PS2)"]} Tool call response { "found": ["puyo puyo tsu (PS2)"]} Final response: "No, you already have it" Google Cloud Final response: "No, you already have it" 09
10. The hard way: GenAI SDK
11. Go GenAI SDK Oficial Google SDK, only for Gemini models Abstraction level: low (basically an 1:1 mapping of the APIs) Supports: Generate Content API, Live API e Batch API Auth via Gemini API and Gemini Enterprise (Vertex AI) github.com/googleapis/go-genai Alternative: ai.google.dev/gemini-api/docs/openai Google Cloud 011
12. Genkit
13. Genkit Supports both Gemini and models from other labs via the plugin system Abstraction level: medium Primitives: flows and prompts (dotprompt) Middleware: supports tools, skills, etc. Official skills: npx skills add genkit-ai/skills Also available for JS/TS, Python and Dart genkit.dev Google Cloud 013
14. Photo restoration with Nano Banana danicat.dev/posts/genkit-go-photo-restoration Google Cloud github.com/danicat/glowup 014
15. Agent Development Kit (ADK)
16. Agent Development Kit (ADK) Supports both Gemini and models from other labs Abstraction level: high Primitives: agents Official skills: uvx google-agents-cli setup Also available for JS/TS, Python, Java and Kotlin adk.dev Google Cloud 016
17. Agent Runtimes
18. Google Cloud Run Serverless container runtime solution. Default target for simple agents. Agent run as a container that responds to requests over HTTP Gemini Enterprise Agent Platform Unified platform to build, deploy, govern, and optimize enterprise-grade AI agents and model-based solutions. Use when leveraging enterprise-grade products like Memory Bank, Sessions, Registry, Gateway, etc. Google Cloud 018
19. Setup for Coding Agents
20. Coding Agent Setup Product skills: - Genkit: npx skills add genkit-ai/skills - ADK: uvx google-agents-cli setup Google Skills: github.com/google/skills (Cloud Run, Agent Platform, etc.) Google Cloud Developer Plugin: - Antigravity: agy plugin install github.com/google/skills/plugins/cloud/google-cloud-developer - Claude: claude plugin marketplace add google/skills claude plugin install google-cloud-developer@google-plugins Google Cloud 020
21. Build the future builders.google
22. Thank you Blog: danicat.dev LinkedIn: linkedin.com/in/petruzalek Twitter: x.com/danicat83 Github: github.com/danicat 022