---
id: ag-ui-a2ui-toolkit
version: "0.0.4"
license: MIT
license_treatment: permissive
maintenance: active
---

# ag-ui-a2ui-toolkit — Framework-agnostic helpers for building A2UI subagent tools — op builders, prompt assembly, history walkers, and request/envelope orchestration shared across framework adapters.

License: permissive · Maintenance: active · Downloads: 667.1K/mo

## What it is and what it does

ag-ui-a2ui-toolkit is a Python library of reusable building blocks for constructing A2UI (agent-to-UI) subagent tools. It provides no framework dependencies itself—instead, it exports constants, operation builders (like create_surface and update_components), prompt composition helpers, state walkers, and orchestration functions that framework-specific adapters (for LangGraph, ADK, Mastra, and others) can wrap with their own decorators and runtime bindings.

The package is designed to be composed into framework adapters rather than used directly in application code. It handles the semantic and structural work of building A2UI requests, envelopes, and prompts, leaving framework integration to the adapter layer. With no runtime dependencies and active maintenance, it serves as a shared foundation for multiple agent frameworks to build A2UI tooling on top of.

Use it for:

- Building a framework adapter (e.g., for LangGraph or ADK) that needs to compose A2UI operations with framework-specific tool decorators
- Assembling A2UI operation envelopes and structured prompts for subagent invocation without framework lock-in
- Managing A2UI state history and context across agent tool calls using the provided helpers
- Generating consistent A2UI tool definitions and schemas across multiple framework implementations

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides framework-agnostic helper functions and constants for building A2UI subagent tools, including operation builders, prompt assembly, state management, and request orchestration that can be composed into agent framework adapters.

Yes, if you are building a framework adapter for A2UI subagent tools or integrating A2UI operations into an agent system. No, if you are looking for a direct end-user agent framework—this is a foundation library meant to be composed into adapters. Install it as a dependency of your framework adapter, not as a standalone tool.

## Install

pip install ag-ui-a2ui-toolkit
uv add ag-ui-a2ui-toolkit
poetry add ag-ui-a2ui-toolkit

## Installing ag-ui-a2ui-toolkit

Before you install: Low friction install with no runtime dependencies. Active maintenance status and recent releases (58 days since last release as of fact sheet date) suggest ongoing development.

License in practice: MIT license permits commercial and private use with minimal restrictions—typical permissive terms for open-source libraries.

Quickstart:

pip install ag-ui-a2ui-toolkit

from ag_ui_a2ui_toolkit import create_surface, build_subagent_prompt

surface = create_surface(...)
prompt = build_subagent_prompt(...)

Requires Python 3.10 or later (supports up to <3.15)

Verify before relying:

- Whether this package is intended for end-user installation or primarily as a dependency for framework adapters (LangGraph, ADK, Mastra, etc.)
- Whether the TypeScript counterpart's API parity claim extends to feature completeness or only surface naming
- Stability guarantees or semantic versioning policy given the 0.0.x version number

## Package facts

- License: MIT (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 667.1K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

A2UI subagent tool helpers, framework-agnostic agent UI toolkit, A2UI operation builders, agent tool prompt assembly, A2UI request orchestration, agent-framework, a2ui, subagent-tools

[View on SkillFed](https://skillfed.io/packages/ag-ui-a2ui-toolkit) · [View on PyPI](https://pypi.org/project/ag-ui-a2ui-toolkit/)