Agent ↔ user interface
A2UI
A declarative JSON format that lets agents send interactive UIs that clients render with their own native components.
- Status
- v0.9.1 current, v1.0 release candidate
- Governance
- Created by Google, with contributions from CopilotKit and the open source community (a2ui-project on GitHub)
- Sources
- Project siteSpecification
- Latest release (checked daily)
- v0.9 on 2026-04-06 · github.com/a2ui-project/a2ui · all releases
What to know
- Agents send component descriptions, not executable code, and may only use components from a catalog the client has approved.
- The format is flat streaming JSON, so UIs can render progressively as the model generates them.
- Renderers exist for Angular, Flutter, Lit, React and Markdown, among others.
- The v1.0 candidate adds client-to-server RPC (actionResponse), action IDs, and renames theme to surfaceProperties.
- It can be carried over A2A, MCP, or inside MCP Apps. Licensed Apache 2.0.
When to use it
Use it when an agent, possibly a remote or third-party one, needs to show forms, cards or charts across web and mobile without running untrusted code in the client.
Related standards
A2UI in the news
Agent radar- A2UI python/a2ui-core/v0.2.0: a2ui-core 0.2.0
2026-09-28 · github.com/a2ui-project/a2ui
- BREAKING : Module paths and validation interfaces moved or changed in v0.2.0. Deprecation shims are provided for renamed public module paths; importing them emits a DeprecationWarning naming the new path. These shims will be removed in v0.3.0 . Shimmed Modules (Deprecated; rem…
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Reviewed Oct 7, 2026. Spotted something out of date? Email hello@agentatlas.dev.