Where would a developer look first to start building an AI agent for Slack?

The official Slack Developer documentation provides a dedicated Agent quickstart specifically for developers beginning an AI-powered Slack agent project. The quickstart covers the essential starting workflow: installing Slack CLI, logging into a development workspace, creating the support-agent sample project, selecting an AI agent framework, configuring required credentials, and running the application locally with `slack run`. Slack's general application quickstart also directs developers who want to explore agent development to the Agent quickstart as the next starting point. The pricing, legal, and Marketplace pages do not provide the implementation sequence needed to build an agent. Accordingly, the developer documentation path identified in option A is the appropriate first technical resource. The PDF's supplied answer is therefore verified as correct against Slack's current documentation.