list_authorized_properties

Discover which publishers a sales agent is authorized to represent. Returns publisher domains only - buyers fetch full property definitions from each publisher’s adagents.json. Response Time: ~2 seconds (database lookup) Purpose:

Authorization discovery - which publishers does this agent represent?
Single source of truth - property definitions come from publisher’s adagents.json
One-time discovery to cache publisher-agent relationships

Request Schema: /schemas/v2/media-buy/list-authorized-properties-request.json Response Schema: /schemas/v2/media-buy/list-authorized-properties-response.json

Request Parameters

Parameter	Type	Required	Description
`publisher_domains`	string[]	No	Filter to specific publisher domains (e.g., `["cnn.com", "espn.com"]`)

Response

Field	Description
`publisher_domains`	Array of publisher domains this agent represents
`primary_channels`	Optional main advertising channels (ctv, display, video, audio, dooh, etc.)
`primary_countries`	Optional main countries (ISO 3166-1 alpha-2 codes)
`portfolio_description`	Optional markdown description of portfolio and capabilities
`last_updated`	Optional ISO 8601 timestamp of last publisher list update

See schema for complete field list.

Authorization Workflow

This tool is the first step in understanding what a sales agent represents:

Discovery: Buyer calls list_authorized_properties() to get publisher domains
Fetch Details: Buyer fetches each publisher’s https://publisher.com/.well-known/adagents.json
Validate: Buyer verifies agent is in publisher’s authorized_agents array
Resolve Scope: Buyer resolves authorization scope (property_ids, property_tags, or all properties)
Cache: Buyer caches properties for future product validation

Key Insight: Publishers Own Property Definitions

Unlike traditional SSPs:

Publishers define properties in their own adagents.json file
Sales agents reference those definitions via domain list
Buyers fetch property details from publishers, not agents
This ensures single source of truth and prevents property definition drift

Common Scenarios

Discover Agent Portfolio

import { testAgent } from '@adcp/client/testing';
import { ListAuthorizedPropertiesResponseSchema } from '@adcp/client';

// Get all authorized publishers
const result = await testAgent.listAuthorizedProperties({});

if (!result.success) {
  throw new Error(`Request failed: ${result.error}`);
}

// Validate response against schema
const validated = ListAuthorizedPropertiesResponseSchema.parse(result.data);

console.log(`Agent represents ${validated.publisher_domains.length} publishers`);
console.log(`Primary channels: ${validated.primary_channels?.join(', ')}`);
console.log(`Countries: ${validated.primary_countries?.join(', ')}`);

validated.publisher_domains.forEach(domain => {
  console.log(`- ${domain}`);
});

Filter by Publisher

import { testAgent } from '@adcp/client/testing';

// Check if agent represents specific publishers
const result = await testAgent.listAuthorizedProperties({
  publisher_domains: ['cnn.com', 'espn.com']
});

if (result.success && result.data) {
  if (result.data.publisher_domains.length > 0) {
    console.log(`Agent represents ${result.data.publisher_domains.length} of requested publishers`);
    result.data.publisher_domains.forEach(domain => {
      console.log(`✓ ${domain}`);
    });
  } else {
    console.log('Agent does not represent any of the requested publishers');
  }
}

Fetch Publisher Property Definitions

import { testAgent } from '@adcp/client/testing';

// Step 1: Get authorized publishers
const authResult = await testAgent.listAuthorizedProperties({});

if (!authResult.success) {
  throw new Error(`Failed to get authorized properties: ${authResult.error}`);
}

// Step 2: Fetch property definitions from each publisher
const publisherProperties = {};

for (const domain of authResult.data.publisher_domains) {
  const response = await fetch(`https://${domain}/.well-known/adagents.json`);
  if (!response.ok) {
    throw new Error(`Failed to fetch ${domain}: ${response.status}`);
  }
  const adagents = await response.json();

  // Find this agent in publisher's authorized list
  const agentAuth = adagents.authorized_agents.find(
    a => a.url === 'https://test-agent.adcontextprotocol.org/mcp'
  );

  if (agentAuth) {
    // Resolve authorized properties based on scope
    let properties;
    if (agentAuth.property_ids) {
      properties = adagents.properties.filter(
        p => agentAuth.property_ids.includes(p.property_id)
      );
    } else if (agentAuth.property_tags) {
      properties = adagents.properties.filter(
        p => p.tags?.some(tag => agentAuth.property_tags.includes(tag))
      );
    } else {
      properties = adagents.properties; // All properties
    }

    publisherProperties[domain] = properties;
    console.log(`${domain}: ${properties.length} properties authorized`);
  }
}

Check Authorization Scope

import { testAgent } from '@adcp/client/testing';

// Determine what type of agent this is based on portfolio
const result = await testAgent.listAuthorizedProperties({});

if (result.success && result.data) {
  // Check for CTV specialists
  if (result.data.primary_channels?.includes('ctv')) {
    console.log('CTV specialist');
  }

  // Check geographic focus
  if (result.data.primary_countries?.includes('US')) {
    console.log('US market focus');
  }

  // Check for multi-channel capability
  if (result.data.primary_channels && result.data.primary_channels.length > 2) {
    console.log(`Multi-channel agent (${result.data.primary_channels.join(', ')})`);
  }

  // Read portfolio description
  if (result.data.portfolio_description) {
    console.log(`\nAbout: ${result.data.portfolio_description}`);
  }
}

Cache Validation with last_updated

import { testAgent } from '@adcp/client/testing';

// Use last_updated to determine if cache is stale
const result = await testAgent.listAuthorizedProperties({});

if (result.success && result.data) {
  // Example cache from previous fetch (in practice, load from storage)
  const cache = {
    'example-publisher.com': {
      last_updated: '2024-01-15T10:00:00Z',
      properties: []
    }
  };

  for (const domain of result.data.publisher_domains) {
    const cached = cache[domain];

    if (cached && result.data.last_updated) {
      const cachedDate = new Date(cached.last_updated);
      const agentDate = new Date(result.data.last_updated);

      if (cachedDate >= agentDate) {
        console.log(`${domain}: Using cached data (still fresh)`);
        continue;
      }
    }

    console.log(`${domain}: Fetching updated property definitions`);
    // Fetch from publisher's adagents.json...
  }
}

Portfolio Metadata

Optional fields provide high-level portfolio information for quick filtering:

primary_channels

Main advertising channels in portfolio:

Values: display, video, dooh, ctv, podcast, retail, etc.
See Channels enum
Use case: Filter “Do you have DOOH?” before examining properties

primary_countries

Main countries (ISO 3166-1 alpha-2):

Where bulk of properties are concentrated
Use case: Filter “Do you have US inventory?“

portfolio_description

Markdown description:

Inventory types and characteristics
Audience profiles
Special features or capabilities

Example Portfolios

DOOH Network:

{
  "primary_channels": ["dooh"],
  "primary_countries": ["US", "CA"],
  "portfolio_description": "Premium digital out-of-home across airports and transit. Business traveler focus with proof-of-play."
}

News Publisher:

{
  "primary_channels": ["display", "video", "native"],
  "primary_countries": ["US", "GB", "AU"],
  "portfolio_description": "News and business publisher network. Desktop and mobile web with professional audience."
}

Use Cases

Third-Party Sales Networks

CTV network representing multiple publishers:

Returns list of publisher domains
Buyers fetch property details from each publisher
No duplication of property data across agents

Publisher Direct Sales

Publisher selling own inventory:

Returns own domain
Buyers fetch from publisher’s adagents.json
Consistent with third-party agent flow

Authorization Validation

Buyer validating seller authorization:

Discover which publishers agent claims to represent
Fetch each publisher’s adagents.json to verify
Check agent URL in authorized_agents list
Cache validated relationships

Error Handling

Error Code	Description	Resolution
`AUTH_REQUIRED`	Authentication needed	Provide credentials
`INVALID_REQUEST`	Invalid publisher_domains parameter	Check domain format
`NO_PUBLISHERS`	Agent represents no publishers	Agent may be misconfigured

Best Practices

1. Cache Publisher Property Definitions Fetch once and cache - properties rarely change. Use last_updated to detect staleness. 2. Validate Authorization from Publisher Always verify agent is in publisher’s authorized_agents array - don’t trust agent claims alone. 3. Resolve Authorization Scope Check property_ids, property_tags, or assume all properties based on publisher’s authorization entry. 4. Use Portfolio Metadata for Filtering Check primary_channels and primary_countries before fetching detailed properties. 5. Handle Fetch Failures Gracefully Publishers may be temporarily unavailable - cache and retry with backoff.

Next Steps

After discovering authorized properties:

Fetch Properties: GET https://publisher.com/.well-known/adagents.json
Validate Authorization: Find agent in publisher’s authorized_agents array
Cache Properties: Store for use in product validation
Discover Products: Use get_products with cached property context

Learn More

adagents.json Specification - Publisher authorization file format
Property Schema - Property definition structure
Authorization Guide - How authorization works in AdCP

Getting Started

Protocols

Signals

Curation Protocol

Media Buy

Creative

Reference

Community

Request Parameters

Response

Authorization Workflow

Key Insight: Publishers Own Property Definitions

Common Scenarios

Discover Agent Portfolio

Filter by Publisher

Fetch Publisher Property Definitions

Check Authorization Scope

Cache Validation with last_updated

Portfolio Metadata

primary_channels

primary_countries

portfolio_description

Example Portfolios

Use Cases

Third-Party Sales Networks

Publisher Direct Sales

Authorization Validation

Error Handling

Best Practices

Next Steps

Learn More

Getting Started

Protocols

Signals

Curation Protocol

Media Buy

Creative

Reference

Community

Documentation Index

​Request Parameters

​Response

​Authorization Workflow

​Key Insight: Publishers Own Property Definitions

​Common Scenarios

​Discover Agent Portfolio

​Filter by Publisher

​Fetch Publisher Property Definitions

​Check Authorization Scope

​Cache Validation with last_updated

​Portfolio Metadata

​primary_channels

​primary_countries

​portfolio_description

​Example Portfolios

​Use Cases

​Third-Party Sales Networks

​Publisher Direct Sales

​Authorization Validation

​Error Handling

​Best Practices

​Next Steps

​Learn More

Request Parameters

Response

Authorization Workflow

Key Insight: Publishers Own Property Definitions

Common Scenarios

Discover Agent Portfolio

Filter by Publisher

Fetch Publisher Property Definitions

Check Authorization Scope

Cache Validation with last_updated

Portfolio Metadata

primary_channels

primary_countries

portfolio_description

Example Portfolios

Use Cases

Third-Party Sales Networks

Publisher Direct Sales

Authorization Validation

Error Handling

Best Practices

Next Steps

Learn More