# MCP Apps vs Agent-User Interaction Protocol (AG-UI)

The map lists them as complementary: sites and agents commonly implement both.

[8 Present](/category/present/) [MCP Apps](/protocols/mcp-apps/) · [8 Present](/category/present/) [Agent-User Interaction Protocol](/protocols/ag-ui/)

|  | [MCP Apps](/protocols/mcp-apps/) MCP Apps | [Agent-User Interaction Protocol](/protocols/ag-ui/) AG-UI |
| --- | --- | --- |
| Lifecycle step | 8 Present: Show a human the result | 8 Present: Show a human the result |
| Answers | How does an MCP tool deliver an interactive UI (chart, form, dashboard) that renders inline in a chat client? | How does an agent stream state, generative UI, messages, and tool activity into a user-facing application in real time? |
| Governed by | modelcontextprotocol GitHub org (ext-apps sub-project); same umbrella as core MCP, which is now stewarded by the Agentic AI Foundation / Linux Foundation per this site's existing 'mcp' record | AG-UI open-source project (github.com/ag-ui-protocol), originated and still primarily stewarded by CopilotKit; biweekly public working group |
| Status (issuer's words) | Active extension to MCP; own repo describes it as extending 'the Model Context Protocol by letting tools declare UI resources' | 1.0 released and frozen; JSON Schema published |
| Version | v2.0.3 (2026-09-25) | 1.0 (2026-09-18) |
| Form / transport | endpoint | endpoint |
| Found at | ui://<resource-id> (declared per-tool, not a fixed site-wide path) | No fixed well-known path; a client is coded against a known agent backend endpoint that emits an AG-UI-compatible event stream over an agreed transport (SSE, WebSockets, webhooks) |
| Implementation | multi-implementation | multi-implementation |
| Evidence | 4 verified | 4 verified, 2 reported |
| Primary use case | Render agent output as a user interface | Render agent output as a user interface |
| Last verified | 2026-10-23 (current) | 2026-10-23 (current) |
| Specification | [https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/2026-01-26/apps.mdx](https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/2026-01-26/apps.mdx) | [https://docs.ag-ui.com/introduction](https://docs.ag-ui.com/introduction) |

## When to use which

- Choose MCP Apps when your question is “How does an MCP tool deliver an interactive UI (chart, form, dashboard) that renders inline in a chat client?” and you accept its maturity: status "Active extension to MCP; own repo describes it as extending 'the Model Context Protocol by letting tools declare UI resources'", implementation multi-implementation.
- Choose Agent-User Interaction Protocol when your question is “How does an agent stream state, generative UI, messages, and tool activity into a user-facing application in real time?” and you accept its maturity: status "1.0 released and frozen; JSON Schema published", implementation multi-implementation.

Guidance is derived from the two records (question, status, implementation, prerequisites, pairings), not from opinion. Each record's page carries its numbered references.

## Read the full articles

- [MCP Apps](/protocols/mcp-apps/): How does an MCP tool deliver an interactive UI (chart, form, dashboard) that renders inline in a chat client?
- [Agent-User Interaction Protocol](/protocols/ag-ui/): How does an agent stream state, generative UI, messages, and tool activity into a user-facing application in real time?

Ask the MCP server to compare any two: the compare-protocols prompt, or get on both ids. [Connect](/connect/).

[mcp-apps.json](/data/protocols/mcp-apps.json) · [ag-ui.json](/data/protocols/ag-ui.json) · [Markdown](/compare/mcp-apps-vs-ag-ui/index.md)