The Big Picture
The Agentic UI ecosystem is rapidly evolving with multiple protocols and frameworks competing and collaborating. As of late 2024/early 2025, the space is consolidating around a few key standards.
Industry Consolidation (Dec 2025)
The Agentic AI Foundation (AAIF) was formed under the Linux Foundation with contributions from major players:
- •Anthropic: Donated MCP
- •Block: Donated goose
- •OpenAI: Contributed AGENTS.md
- •Google: Donated A2A Protocol
Key Insight
This signals industry alignment on open standards for agentic systems. The major AI companies are collaborating rather than fragmenting the ecosystem.
MCP - Model Context Protocol
Creator: Anthropic (Nov 2024)
Status: 97M monthly SDK downloads, 10,000+ public servers
What it solves
Universal connection between AI agents and external systems (tools, data, context).
Core Primitives
- 1.Resources - Read-only data access
- 2.Tools - Actions agents can perform
- 3.Prompts - Reusable prompt templates
Key Insight
MCP is the “USB-C of AI” - implement once, connect to the entire ecosystem.
Security Note
April 2025 research identified vulnerabilities (prompt injection, tool permissions). Always validate and sandbox.
AG-UI - Agent User Interaction Protocol
Creator: CopilotKit (May 2025)
Status: Native in CopilotKit v1.50+, adopted by Microsoft, Oracle, AWS
What it solves
Real-time, bidirectional communication between agent backends and user interfaces.
Core Concept
Single ordered sequence of JSON events over HTTP/SSE.
Event Categories
- •Lifecycle - Run start/end, steps
- •Text - Streaming messages
- •Tool - Invocations, results
- •State - Snapshots, patches
- •Custom - App-specific events
Key Insight
Unlike request-response APIs, AG-UI maintains a continuous connection allowing agents to push updates, request input, and synchronize state.
A2UI - Agent-to-User Interface
Creator: Google (Dec 2025)
Status: v0.8 Public Preview
What it solves
Safe, cross-platform generative UI from agents without code execution.
Core Approach
- •Declarative JSON describing UI intent
- •Client maintains component catalog (Card, Button, TextField, etc.)
- •Agent can only reference pre-approved components
- •No arbitrary code execution
Two Approaches Emerging
| A2UI (Google) | MCP Apps | |
|---|---|---|
| Philosophy | Native-first | Web-first |
| Execution | Declarative only | Sandboxed iframes |
| Platforms | Any (Flutter, React, native) | Primarily web |
| Flexibility | Limited to catalog | Full HTML/JS |
Key Insight
A2UI trades flexibility for security and cross-platform support.
A2A - Agent-to-Agent Protocol
Creator: Google (Donated to Linux Foundation)
What it solves
Agent coordination when they don't share memory, tools, or context.
Use Case
Orchestrating multiple specialized agents to complete complex tasks.
Framework Comparison
CopilotKit
Best for: React developers building in-app AI copilots
Approach: “Agentic last-mile” - connect any agent backend to React UI
Key Features
- •
useAgenthook for programmatic control - •Shared state between agent and app
- •Human-in-the-loop workflows
- •Multi-agent execution
Vercel AI SDK
Best for: TypeScript/Next.js full-stack AI apps
Approach: Unified API across all AI providers
Key Features
- •Provider-agnostic (OpenAI, Anthropic, Google, etc.)
- •
useChat,useCompletionhooks - •AI SDK 6 Agent abstraction
- •LangChain/LangGraph adapters
OpenAI Agents SDK
Best for: Python developers, OpenAI-centric stacks
Approach: Lightweight multi-agent framework
Key Features
- •Agent definition with instructions + tools
- •Handoffs between agents
- •Built-in guardrails
- •AgentKit visual builder
LangGraph
Best for: Complex, stateful agent workflows
Approach: Graph-based agent orchestration
Key Features
- •Cycles and loops in agent logic
- •Persistent state across runs
- •Human-in-the-loop patterns
- •Time-travel debugging
Current State of the Ecosystem
Mature & Production-Ready
- •MCP (widely adopted)
- •Vercel AI SDK (20M+ downloads)
- •CopilotKit (100k+ developers)
Growing Rapidly
- •AG-UI (official Microsoft, Oracle adoption)
- •OpenAI Agents SDK
Early/Preview
- •A2UI (v0.8 preview)
- •MCP Apps (new extension)
Trends to Watch
- 1.Chat UI fading - Moving to task-oriented, knob/slider interfaces
- 2.Multimodal - Voice, gesture, haptics integration
- 3.Hyper-personalization - UI adapts to user emotional state
- 4.Transparency - Visible “thought logs” and confidence indicators
- 5.Protocol convergence - MCP + AG-UI + A2UI working together
Decision Framework
Choose CopilotKit + AG-UI when:
- •Building React apps with AI copilots
- •Need real-time agent-UI synchronization
- •Want framework-agnostic agent backends
Choose Vercel AI SDK when:
- •Full-stack Next.js application
- •Need provider flexibility
- •Prefer unified TypeScript API
Choose A2UI when:
- •Cross-platform (web + mobile + desktop)
- •Security is paramount
- •Generating UI components dynamically
Choose MCP Apps when:
- •Building interactive tools for Claude/AI assistants
- •Need rich web UI capabilities
- •Web-centric deployment