Agent Development Kit (ADK) frameworks differ in detail but share a lifecycle: define capabilities, configure models, register tools, deploy, observe, version, retire. Knowing this skeleton helps you map any specific ADK onto a mental model.
Define capabilities
What does this agent do? Inputs, outputs, constraints. Define before picking the model. The capability spec doubles as the eval set design.
Configure model and constraints
Model choice (size, provider, fallbacks). Temperature, max tokens, guardrails. Tool list. System prompt or instruction. Versioned together so you can roll back any one piece.
Register tools
Each tool: name, description (the model reads this), JSON schema, handler function. Authorization scope. Rate limit. Idempotency contract. Tools are first-class artifacts; share them across agents.
Deploy and version
Agents have versions. Rollouts are gradual (10% → 50% → 100%). Old versions linger for rollback. Tied to model versions: pin the model so a provider update doesn't silently change behavior.
Observe and retire
Trace every tool call, every model call, every decision. Watch quality metrics over time. Retire agents that aren't used or are superseded — they accrue maintenance cost.