Native UI forms
for AI agents

See It In Action

Light and dark themes — with the built-in multilingual AI-generated UI security warning.

Light mode — dropdown, checkboxes, text field, slider

Dark mode — radio group, number input, dropdown

The Problem with Chat Loops

Agents asking humans questions one at a time is painfully inefficient.

Where a2native Fits in the Agentic Protocol Stack

Four complementary protocols — each for a different layer of agent interaction.

Features

Everything an agent needs to gather structured human input.

Input Format — Three Modes

a2native auto-detects the format. Detection priority: AG-UI → Google A2UI → a2native.

Mode 1 — a2native (simplest, recommended for new integrations)

a2native's own format: one JSON object in, one JSON object out. No streaming, no protocol overhead.  JSON Schema ↗  ·  a2n schema

// Input — a2native
{
  "title":     "Deploy to production",
  "timeout":   60,
  "theme":     { "dark_mode": true, "accent_color": "#6C63FF" },
  "components": [
    { "id": "env", "type": "dropdown", "label": "Environment",
      "options": [
        { "value": "prod",  "label": "Production" },
        { "value": "stag", "label": "Staging" }
      ]},
    { "id": "ok", "type": "button", "label": "Deploy", "action": "submit" }
  ]
}

// Output — a2native
{ "status": "submitted", "values": { "env": "prod" } }

Mode 2 — Google A2UI (native surface rendering)

Natively accepts Google A2UI v0.8+ surfaceUpdate / beginRendering JSONL. Emits A2UI userAction output. Any agent SDK built for Google A2UI can drive a2native with no adaptation. A2UI Row maps to horizontal layout; Column/List to vertical card groups.

// Input — Google A2UI JSONL
{"surfaceUpdate":{"surfaceId":"form1","components":[
  {"id":"env","component":{"MultipleChoice":{
    "options":[{"label":{"literalString":"Production"},"value":"prod"}],
    "maxAllowedSelections":1,"variant":"dropdown"}}},
  {"id":"lbl","component":{"Text":{"text":{"literalString":"Deploy"}}}},
  {"id":"btn","component":{"Button":{"child":"lbl","action":{"name":"submit"}}}}
]}}

// Output — A2UI userAction
{"userAction":{"name":"submit","surfaceId":"form1","sourceComponentId":"btn",
  "timestamp":"2026-01-01T12:00:00Z","context":{"env":"prod"}}}

Mode 3 — AG-UI (frontend tool handler)

Acts as an AG-UI frontend tool: receives TOOL_CALL_START / TOOL_CALL_ARGS / TOOL_CALL_END events, renders the form, emits a TOOL_CALL_RESULT. Tool call args can be in a2native or Google A2UI format — both are auto-detected.

// Input — AG-UI event stream
{"type":"RUN_STARTED","threadId":"t1","runId":"r1"}
{"type":"TOOL_CALL_START","toolCallId":"tc1","toolCallName":"show_form"}
{"type":"TOOL_CALL_ARGS","toolCallId":"tc1","delta":"{"title":"Deploy","}
{"type":"TOOL_CALL_ARGS","toolCallId":"tc1","delta":""components":[{"id":"ok","type":"button","label":"Go","action":"submit"}]}"}
{"type":"TOOL_CALL_END","toolCallId":"tc1"}

// Output — AG-UI TOOL_CALL_RESULT
{"type":"TOOL_CALL_RESULT","messageId":"tc1-result","toolCallId":"tc1",
 "content":"{"status":"submitted","values":{}}","role":"tool"}

⚠ Security Considerations

a2native is called by AI agents automatically. Understand the risks.

The banner above appears at the top of every a2native window. It cannot be hidden by the form spec.

Usage with AI Agents

Tell your agent — no SDK or setup required.

Use `a2native` (`a2n`) to collect structured
input from the user instead of asking
questions in chat.

Quick reference:
  a2n '{"components":[...]}' # one-shot
  a2n --session UUID '...'   # multi-turn
  a2n help                   # full schema

Always include at least one submit button:
  {"id":"ok","type":"button",
   "label":"Submit","action":"submit"}

{
  "name": "show_form",
  "description": "Show a native UI form to the user and return their input. Use this instead of asking questions in chat.",
  "parameters": {
    "type": "object",
    "properties": {
      "title":      { "type": "string" },
      "components": { "type": "array" }
    },
    "required": ["components"]
  }
}

Python example

import subprocess, json

form = {
  "title": "Configure deployment",
  "components": [
    {"id": "env", "type": "dropdown", "label": "Environment",
     "options": [{"value":"prod","label":"Production"},{"value":"stg","label":"Staging"}],
     "required": True},
    {"id": "tag",  "type": "text-field", "label": "Image tag",
     "placeholder": "v1.2.3", "required": True},
    {"id": "go",   "type": "button",     "label": "Deploy", "action": "submit"},
  ]
}

result = subprocess.run(["a2n", json.dumps(form)],
                        capture_output=True, text=True)
data = json.loads(result.stdout)

if data["status"] == "submitted":
    deploy(data["values"]["env"], data["values"]["tag"])

JavaScript SDK

# npm install @a2native/js
import { showForm } from "@a2native/js";

const result = await showForm({
  title: "Pick a model",
  components: [
    { id: "model", type: "radio-group", label: "Model",
      options: [{ value: "gpt-4o", label: "GPT-4o" },
                { value: "claude", label: "Claude" }],
      required: true },
    { id: "ok", type: "button", label: "Select", action: "submit" },
  ],
});
// result.status === "submitted", result.values.model === "gpt-4o"

Session Mode — Multi-Turn Interactions

Inspired by agent-browser's client-daemon pattern: the window lives, the agent turns are short. Pass the same UUID on every turn and the form updates in place — no flicker, no re-spawn.

# Turn 1 — opens the window (daemon spawns in background)
echo '{"title":"Wizard 1/3","components":[...]}' | a2n --session abc123
# → {"status":"submitted","values":{...}}

# Turn 2 — same window, new form (no new window spawned)
echo '{"title":"Wizard 2/3","components":[...]}' | a2n --session abc123

# Turn 3 — final step
echo '{"title":"Wizard 3/3","components":[...]}' | a2n --session abc123

# Close the window when done
a2n --close abc123

For HTTP/SSE and WebSocket daemon usage, see the Advanced Usage → page.

Get Started

Install via Cargo, or download a pre-built binary.

# Install from crates.io
cargo install a2native

# Or build from source
git clone https://github.com/a2native/a2native.git
cd a2native && cargo build --release

# Show help + full schema reference
a2n help

# One-shot: JSON as inline argument
a2n '{"components":[{"id":"n","type":"text-field","label":"Name","required":true}]}'

# One-shot: JSON from stdin
echo '{"title":"Pick one","components":[...]}' | a2n

For multi-turn sessions and HTTP/SSE or WebSocket integration, see the Advanced Usage → page.