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Meta Events Proposal

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Summary

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Problem Statement

Currently, AG-UI events are tightly coupled to agent runs. There’s no standardized way to attach user feedback, annotations, or external signals to the event stream that are independent of the agent’s execution lifecycle.

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Motivation

AG-UI is extended with MetaEvents, a new class of events that can occur at any point in the event stream, independent of agent runs. MetaEvents provide a way to attach annotations, signals, or feedback to a serialized stream. They may originate from users, clients, or external systems rather than from agents. Examples include reactions such as thumbs up/down on a message.

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Status

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Detailed Specification

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Overview

This proposal introduces:
  • A new MetaEvent type for side-band annotations
  • Events that can appear anywhere in the stream
  • Support for user feedback, tags, and external annotations
  • Extensible payload structure for application-specific data

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New Type: MetaEvent

type MetaEvent = BaseEvent & {
  type: EventType.META
  /**
   * Application-defined type of the meta event.
   * Examples: "thumbs_up", "thumbs_down", "tag", "note"
   */
  metaType: string

  /**
   * Application-defined payload.
   * May reference other entities (e.g., messageId) or contain freeform data.
   */
  payload: Record<string, unknown>
}

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Key Characteristics

  • Run-independent: MetaEvents are not tied to any specific run lifecycle
  • Position-flexible: Can appear before, between, or after runs
  • Origin-diverse: May come from users, clients, or external systems
  • Extensible: Applications define their own metaType values and payload schemas

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Implementation Examples

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User Feedback

Thumbs Up: 
{
  "id": "evt_123",
  "ts": 1714063982000,
  "type": "META",
  "metaType": "thumbs_up",
  "payload": {
    "messageId": "msg_456",
    "userId": "user_789"
  }
}
Thumbs Down with Reason: 
{
  "id": "evt_124",
  "ts": 1714063985000,
  "type": "META",
  "metaType": "thumbs_down",
  "payload": {
    "messageId": "msg_456",
    "userId": "user_789",
    "reason": "inaccurate",
    "comment": "The calculation seems incorrect"
  }
}

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Annotations

User Note: 
{
  "id": "evt_789",
  "ts": 1714064001000,
  "type": "META",
  "metaType": "note",
  "payload": {
    "text": "Important question to revisit",
    "relatedRunId": "run_001",
    "author": "user_123"
  }
}
Tag Assignment: 
{
  "id": "evt_890",
  "ts": 1714064100000,
  "type": "META",
  "metaType": "tag",
  "payload": {
    "tags": ["important", "follow-up"],
    "threadId": "thread_001"
  }
}

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External System Events

Analytics Event: 
{
  "id": "evt_901",
  "ts": 1714064200000,
  "type": "META",
  "metaType": "analytics",
  "payload": {
    "event": "conversation_shared",
    "properties": {
      "shareMethod": "link",
      "recipientCount": 3
    }
  }
}
Moderation Flag: 
{
  "id": "evt_902",
  "ts": 1714064300000,
  "type": "META",
  "metaType": "moderation",
  "payload": {
    "action": "flag",
    "messageId": "msg_999",
    "category": "inappropriate_content",
    "confidence": 0.95
  }
}

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Common Meta Event Types

While applications can define their own types, these are commonly used:
MetaTypeDescriptionTypical Payload
thumbs_upPositive feedback{ messageId, userId }
thumbs_downNegative feedback{ messageId, userId, reason? }
noteUser annotation{ text, relatedId?, author }
tagCategorization{ tags[], targetId }
bookmarkSave for later{ messageId, userId }
copyContent copied{ messageId, content }
shareContent shared{ messageId, method }
ratingNumeric rating{ messageId, rating, maxRating }

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Use Cases

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User Feedback Collection

Capture user reactions to agent responses for quality improvement.

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Conversation Annotation

Allow users to add notes, tags, or bookmarks to important parts of conversations.

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Analytics and Tracking

Record user interactions and behaviors without affecting agent execution.

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Content Moderation

Flag or mark content for review by external moderation systems.

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Collaborative Features

Enable multiple users to annotate or comment on shared conversations.

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Audit Trail

Create a complete record of all interactions, not just agent responses.

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Implementation Considerations

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Client SDK Changes

TypeScript SDK:
  • New MetaEvent type in @ag-ui/core
  • Helper functions for common meta event types
  • MetaEvent filtering and querying utilities
Python SDK:
  • MetaEvent class implementation
  • Meta event builders for common types
  • Event stream filtering capabilities

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Testing Strategy

  • Unit tests for MetaEvent creation and validation
  • Integration tests with mixed event streams
  • Performance tests with high-volume meta events
  • Security tests for payload validation

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References