Top ANNOTATION GitHub Repositories & Tools (2026)

Annotate terminal text, review documents and agent replies in Herdr, and send the feedback straight back to the agent.

Computer Vision Annotation Tool (CVAT) is a leading platform for building high-quality visual datasets for vision AI. It offers open-source, cloud, and enterprise products, as well as labeling services, for image, video, and 3D annotation with AI-assisted labeling, quality assurance, team collaboration, analytics, and developer APIs.

A fast type checker and language server for Python

Code as configuration. Annotate a Java entity with @Erupt and ship a production-grade admin backend in minutes — UI, RBAC, audit logs and APIs, all generated at runtime. No codegen, no frontend.

Add image annotation functionality to any web page with a few lines of JavaScript.

Your new favorite, free, and open source screenshot tool

Ensure Android runtime permissions using annotations only

PDF Rendering and Viewing API in Java

Auditable human-feedback annotation, review, provenance, and frozen training-data export.

Annotate Markdown in the terminal: select, comment, looks-good, delete; send the review to your agent.

📝 Annotation tool for macOS