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Content types

Base App supports various XMTP content types for rich messaging capabilities. This document outlines all supported content types, including custom types for Quick Actions and Intent. XMTP uses content types to define the structure and meaning of message types. We’ll outline the standard and custom XMTP content types you can utilize in your agent.

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XMTP Content Types

Text Messages
  • Content Type: xmtp.org/text:1.0
  • Purpose: Basic text messaging
  • Usage: Default for plain text
Attachments
  • Content Type: xmtp.org/attachment:1.0
  • Purpose: File attachments (inline)
  • Usage: Send files directly in messages
Remote Static Attachments
  • Content Type: xmtp.org/remoteStaticAttachment:1.0
  • Purpose: Remote file attachments via URLs
  • Usage: Reduce message size
Reactions
  • Content Type: xmtp.org/reaction:1.0
  • Purpose: Emoji reactions
  • Usage: React to messages with emojis
  • Note: Does not trigger read receipts
Replies
  • Content Type: xmtp.org/reply:1.0
  • Purpose: Threaded conversations
  • Usage: Reply to specific messages
Group Management
  • Content Types:
    • xmtp.org/group_membership_change:1.0
    • xmtp.org/group_updated:1.0
  • Purpose: Membership & group metadata updates
  • Usage: Automatic system messages
Read Receipts
  • Content Type: xmtp.org/readReceipt:1.0
  • Purpose: Read confirmations
  • Usage: Sent automatically
Transactions (Wallet Send Calls)
  • Content Type: xmtp.org/walletSendCalls:1.0
  • Purpose: Request wallet actions from users
Transaction Receipts
  • Content Type: xmtp.org/transactionReference:1.0
  • Purpose: Share blockchain transaction info

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Base App Content Types

There are content types developed by the Base App team for agents in Base App. Other XMTP clients may not support these content types. Quick Actions (coinbase.com/actions:1.0) Purpose: Present interactive buttons in a message Structure: 
type ActionsContent = {
  id: string;
  description: string;
  actions: Action[];
  expiresAt?: string;
};

type Action = {
  id: string;
  label: string;
  imageUrl?: string;
  style?: 'primary' | 'secondary' | 'danger';
  expiresAt?: string;
};
Validation Rules:
  • id, description are required
  • actions must be 1–10 items with unique IDs
  • Style must be one of: primary, secondary, danger
Fallback: 
[Description]

[1] [Action Label 1]
[2] [Action Label 2]
...
Reply with the number to select
Example: Payment Options 
{
  "id": "payment_alice_123",
  "description": "Choose amount to send to Alice",
  "actions": [
    { "id": "send_10", "label": "Send $10", "style": "primary" },
    { "id": "send_20", "label": "Send $20", "style": "primary" },
    { "id": "custom_amount", "label": "Custom Amount", "style": "secondary" }
  ],
  "expiresAt": "2024-12-31T23:59:59Z"
}
Manifest Embed Example

Example of Quick Actions message

Intent (coinbase.com/intent:1.0) Purpose: User expresses choice from Quick Actions Structure: 
type IntentContent = {
  id: string;
  actionId: string;
  metadata?: Record<string, string | number | boolean | null>;
};
Validation Rules:
  • id, actionId required
  • Must match corresponding Actions
  • metadata is optional, <10KB
Fallback: 
User selected action: [actionId]
Example: Intent Message 
{
  id: 'payment_alice_123',
  actionId: 'send_10',
  metadata: {
    timestamp: Date.now(),
    actionLabel: 'Send $10'
  }
}
Analytics dashboard with charts

Example of Intent Message