How to Build Custom AI Plugins: Full SDK Guide & Live Build

Sometimes the marketplace doesn't have exactly what you need. In this technical deep dive, we explore the Claude Co-work Plugin SDK and learn how to build, test, and deploy a custom plugin from scratch.
Whether you're connecting to internal legacy systems, handling proprietary logic, or filling a gap in your existing workflow, this video provides the blueprint for extending your AI’s runtime capabilities.
In this video, we cover:
- The 3 Signals to Build Custom: Internal APIs, Proprietary Logic, and Workflow Gaps.
- The 4 Pillars of a Plugin:
1. Manifest File (plugin.json): Identity and Permissions.
2. Tool Definitions (tools.json): How the AI invokes the tool.
3. Schema Definition (schema.json): Data input/output shapes.
4. Runtime Handler (Python): The code that does the heavy lifting.
- Live Project: Building a PDF Watermarker plugin that stamps branded logos onto documents at scale.
- The 3-Phase Testing Strategy: Unit testing, local co-work mode, and edge-case validation.
- Marketplace Submission: A step-by-step guide to zipping your folder and submitting it to the Anthropic developer portal.
- Enterprise Use Cases: Internal CRM connectors, compliance checkers, and custom report generators.
The Golden Rule of Plugins: Build a custom plugin when the marketplace cannot fill your specific capability gap.

Видео How to Build Custom AI Plugins: Full SDK Guide & Live Build канала Analytics Vidhya