adcontextprotocol · bokelley · Jan 24, 2026 · Jan 24, 2026
diff --git a/.changeset/tricky-ideas-try.md b/.changeset/tricky-ideas-try.md
@@ -0,0 +1,4 @@
+---
+---
+
+docs: Document property_features field for governance agent discovery in adagents.json
diff --git a/docs/governance/property/adagents.mdx b/docs/governance/property/adagents.mdx
@@ -65,6 +65,7 @@ The file must be valid JSON with UTF-8 encoding and return HTTP 200 status.
   - **`domain`** *(optional)*: Primary domain of managing entity
   - **`seller_id`** *(optional)*: Seller ID from IAB Tech Lab sellers.json
   - **`tag_id`** *(optional)*: TAG Certified Against Fraud ID
+  - **`privacy_policy_url`** *(optional)*: URL to entity's privacy policy for consumer consent flows
 
 **`properties`** *(optional)*: Array of properties covered by this file (canonical property definitions)
 
@@ -78,6 +79,14 @@ The file must be valid JSON with UTF-8 encoding and return HTTP 200 status.
 
 **`last_updated`** *(optional)*: ISO 8601 timestamp of last modification
 
+**`property_features`** *(optional)*: Array of governance agents that provide data about properties in this file
+  - **`url`** *(required)*: Agent's API endpoint URL (governance agent implementing property governance tasks)
+  - **`name`** *(required)*: Human-readable name of the vendor/agent (e.g., "Scope3", "TAG", "OneTrust")
+  - **`features`** *(required)*: Array of feature IDs this agent provides (e.g., `["carbon_score", "gdpr_compliant"]`)
+  - **`publisher_id`** *(optional)*: Publisher's identifier at this agent (for lookup)
+
+This field enables **governance agent discovery** - buyers can find which agents have compliance, sustainability, or quality data for properties without querying every possible agent.
+
 ## URL Reference Pattern
 
 For publishers with complex infrastructure or CDN distribution, `adagents.json` can reference an authoritative URL instead of containing the full structure inline.
@@ -357,7 +366,8 @@ Large network using tags for grouping efficiency:
     "email": "adops@meta.com",
     "domain": "meta.com",
     "seller_id": "pub-meta-12345",
-    "tag_id": "12345"
+    "tag_id": "12345",
+    "privacy_policy_url": "https://www.meta.com/privacy/policy"
   },
   "properties": [
     {
@@ -458,6 +468,121 @@ Different agents for different channels:
 }
 ```
 
+### Example 3: Publisher with Governance Agent References
+
+Publishers can declare which governance agents have data about their properties using `property_features`. This enables buyers to discover where to get compliance, sustainability, and quality data.
+
+```json
+{
+  "$schema": "https://adcontextprotocol.org/schemas/v2/adagents.json",
+  "contact": {
+    "name": "Premium News Publisher",
+    "email": "adops@news.example.com",
+    "domain": "news.example.com"
+  },
+  "properties": [
+    {
+      "property_id": "news_main",
+      "property_type": "website",
+      "name": "News Example",
+      "identifiers": [
+        {"type": "domain", "value": "news.example.com"}
+      ],
+      "tags": ["premium", "news"],
+      "publisher_domain": "news.example.com"
+    }
+  ],
+  "tags": {
+    "premium": {
+      "name": "Premium Properties",
+      "description": "High-quality, brand-safe properties"
+    },
+    "news": {
+      "name": "News Properties",
+      "description": "News and journalism content"
+    }
+  },
+  "authorized_agents": [
+    {
+      "url": "https://sales.news.example.com",
+      "authorized_for": "All news properties",
+      "authorization_type": "property_tags",
+      "property_tags": ["news"]
+    }
+  ],
+  "property_features": [
+    {
+      "url": "https://api.scope3.com",
+      "name": "Scope3",
+      "features": ["carbon_score", "sustainability_grade"],
+      "publisher_id": "pub_news_12345"
+    },
+    {
+      "url": "https://api.tagtoday.net",
+      "name": "TAG",
+      "features": ["tag_certified_against_fraud", "tag_brand_safety_certified"]
+    },
+    {
+      "url": "https://api.onetrust.com",
+      "name": "OneTrust",
+      "features": ["gdpr_compliant", "tcf_registered", "ccpa_compliant"],
+      "publisher_id": "ot_news_67890"
+    }
+  ],
+  "last_updated": "2025-01-10T18:00:00Z"
+}
+```
+
+**Why this works**:
+- Publishers declare relationships with governance agents upfront
+- Buyers discover governance agents by reading adagents.json (no need to query every possible agent)
+- The `publisher_id` field helps agents look up the publisher's data efficiently
+- Feature IDs tell buyers what data types are available without querying
+
+## Governance Agent Discovery
+
+The `property_features` field solves a key discovery problem: how does a buyer know which governance agents have data about a given property?
+
+```mermaid
+sequenceDiagram
+    participant Buyer as Buyer Agent
+    participant PubDomain as Publisher Domain
+    participant Scope3 as Scope3 Agent
+    participant OneTrust as OneTrust Agent
+
+    Buyer->>PubDomain: GET /.well-known/adagents.json
+    PubDomain-->>Buyer: adagents.json with property_features
+
+    Note over Buyer: Extract governance agents from property_features
+
+    par Query governance agents
+        Buyer->>Scope3: list_property_features
+        Scope3-->>Buyer: Available features (carbon_score, etc.)
+    and
+        Buyer->>OneTrust: list_property_features
+        OneTrust-->>Buyer: Available features (gdpr_compliant, etc.)
+    end
+
+    Note over Buyer: Create property lists on each governance agent
+
+    Buyer->>Scope3: create_property_list(filters, brand_manifest)
+    Buyer->>OneTrust: create_property_list(filters, brand_manifest)
+```
+
+### When to Use property_features
+
+| Scenario | Use property_features? |
+|----------|------------------------|
+| Publisher has carbon scoring from Scope3 | ✅ Yes |
+| Publisher is TAG certified | ✅ Yes |
+| Publisher tracks consent via OneTrust | ✅ Yes |
+| Publisher self-reports brand safety | ❌ No - use property tags |
+| Sales agent provides quality data | ❌ No - that's agent capability |
+
+### Vendor Extensions
+
+Governance agents can include vendor-specific data in feature definitions via an `ext` block. See [list_property_features](/docs/governance/property/tasks/list_property_features#vendor-extensions) for details.
+
 ## Fetching and Validating
 
 ### Using the AdAgents.json Builder
@@ -620,14 +745,14 @@ The Python library handles validation automatically when fetching - if the adage
 
 After implementing adagents.json validation:
 
-1. **Integrate with Product Discovery**: Use [`get_products`](../../media-buy/task-reference/get_products) to discover inventory
-2. **Validate at Purchase**: Check authorization before calling [`create_media_buy`](../../media-buy/task-reference/create_media_buy)
+1. **Integrate with Product Discovery**: Use [`get_products`](/docs/media-buy/task-reference/get_products) to discover inventory
+2. **Validate at Purchase**: Check authorization before calling [`create_media_buy`](/docs/media-buy/task-reference/create_media_buy)
 3. **Cache Property Mappings**: Store resolved properties for efficient validation
 4. **Monitor Authorization**: Track validation success rates and unauthorized attempts
 
 ## Learn More
 
 - [AdCP Basics: Authorized Properties](https://bokonads.com/p/adcp-basics-authorized-properties) - Accessible introduction to AdCP authorization
-- [list_authorized_properties](../../media-buy/task-reference/list_authorized_properties) - Discover publisher domains an agent represents
+- [list_authorized_properties](/docs/media-buy/task-reference/list_authorized_properties) - Discover publisher domains an agent represents
 - [Property Schema](https://adcontextprotocol.org/schemas/v2/core/property.json) - Property definition structure
 - [AdAgents.json Builder](https://adcontextprotocol.org/adagents) - Web-based validator and creator
diff --git a/docs/governance/property/index.mdx b/docs/governance/property/index.mdx
@@ -11,20 +11,21 @@ Property Governance standardizes how advertising properties (websites, apps, CTV
 
 ## Overview
 
-Property Governance addresses four distinct concerns:
+Property Governance addresses five distinct concerns:
 
 | Concern | Question | Owner | Mechanism |
 |---------|----------|-------|-----------|
 | **Property Identity** | What properties exist? | Publishers | `adagents.json` properties array |
 | **Sales Authorization** | Who can sell this property? | Publishers | `adagents.json` authorized_agents |
+| **Governance Agent Discovery** | Who has data about this property? | Publishers | `adagents.json` property_features |
 | **Property Data** | What do we know about this property? | Data providers | Governance agents via `list_property_features` |
 | **Property Selection** | Which properties meet my requirements? | Buyers | Property lists with filters |
 
-The first two are **publisher-side declarations** via adagents.json. The last two are **buyer-side operations** that consume property data from governance agents.
+The first three are **publisher-side declarations** via adagents.json. The last two are **buyer-side operations** that consume property data from governance agents.
 
 ## Publisher Side: adagents.json
 
-Publishers declare their properties and authorize sales agents via `/.well-known/adagents.json`:
+Publishers declare their properties, authorize sales agents, and reference governance agents via `/.well-known/adagents.json`:
 
 ```json
 {
@@ -44,11 +45,43 @@ Publishers declare their properties and authorize sales agents via `/.well-known
       "authorization_type": "property_ids",
       "property_ids": ["example_site"]
     }
+  ],
+  "property_features": [
+    {
+      "url": "https://api.scope3.com",
+      "name": "Scope3",
+      "features": ["carbon_score", "sustainability_grade"]
+    },
+    {
+      "url": "https://api.onetrust.com",
+      "name": "OneTrust",
+      "features": ["gdpr_compliant", "tcf_registered"]
+    }
   ]
 }
 ```
 
-See the [adagents.json Tech Spec](./adagents) for complete documentation.
+### Governance Agent Discovery via property_features
+
+The `property_features` array solves a key discovery problem: **how does a buyer know which governance agents have data about a given property?**
+
+Without `property_features`, buyers would need to query every possible governance agent to find out who has compliance, sustainability, or quality data. With `property_features`, publishers declare these relationships upfront:
+
+| Field | Purpose |
+|-------|---------|
+| `url` | Governance agent's API endpoint |
+| `name` | Human-readable agent name (e.g., "Scope3", "TAG", "OneTrust") |
+| `features` | Feature IDs this agent provides (e.g., `carbon_score`, `gdpr_compliant`) |
+| `publisher_id` | Optional identifier for looking up this publisher at the agent |
+
+**Example use cases:**
+- **Sustainability**: Publisher declares Scope3 tracks their carbon emissions
+- **Compliance**: Publisher declares OneTrust manages their consent data
+- **Certification**: Publisher declares TAG has verified their fraud prevention
+
+Buyers read `property_features` from adagents.json, then query only the relevant governance agents for detailed data.
+
+See the [adagents.json Tech Spec](/docs/governance/property/adagents) for complete documentation including examples and the discovery workflow.
 
 ## Buyer Side: Property Data and Selection
 
@@ -113,8 +146,14 @@ A buyer agent typically works with **multiple governance agents** (consent, bran
 
 ```mermaid
 flowchart TB
+    subgraph Publisher["PUBLISHER (adagents.json)"]
+        P1["properties: identity"]
+        P2["authorized_agents: sales auth"]
+        P3["property_features: governance refs"]
+    end
+
     subgraph Buyer["BUYER AGENT"]
-        B1[Source of truth for compliant list]
+        B1[Discovers governance agents from adagents.json]
         B2[Aggregates results from specialized agents]
         B3[Issues auth_tokens for sellers]
     end
@@ -130,66 +169,24 @@ flowchart TB
         SE2[Uses cached lists for bid-time decisions]
     end
 
+    Publisher -->|property_features discovery| Buyer
     Buyer -->|create_property_list + webhooks| CA
     Buyer -->|create_property_list + webhooks| S3
     Buyer -->|create_property_list + webhooks| BS
 
     Buyer -->|get_property_list with auth_token| Seller
 ```
 
-## Campaign Lifecycle
-
-Property governance operates across three distinct timing contexts. The key principle: **all governance evaluation happens at setup time**, with bid-time decisions using only cached data.
-
-```mermaid
-sequenceDiagram
-    participant O as Orchestrator
-    participant G as Governance Agent
-    participant D as Decisioning Platform
-
-    rect rgb(240, 248, 255)
-    Note over O,D: Phase 1: Campaign Planning (minutes-hours)
-    O->>G: create_property_list(filters, brand_manifest)
-    G-->>O: list_id, auth_token
-    O->>D: Share list_id + auth_token
-    D->>G: get_property_list(list_id, auth_token, resolve=true)
-    G-->>D: identifiers[] (pass/fail list, no scores)
-    D->>G: Register webhook for list updates
-    D->>D: Cache locally (optionally as AXE segments)
-    end
-
-    rect rgb(255, 248, 240)
-    Note over O,D: Phase 2: Bid Time (under 100ms, NO governance calls)
-    D->>D: Check domain against cached allowlist
-    Note right of D: May use AXE axei/axex segments<br/>or direct domain lookup
-    D->>D: Pass → bid, Fail → skip
-    end
-
-    rect rgb(248, 255, 240)
-    Note over O,D: Phase 3: Monitoring (during flight)
-    G-->>D: Webhook: list changed (counts only)
-    D->>G: get_property_list(list_id, auth_token, resolve=true)
-    G-->>D: Updated identifiers[]
-    D->>D: Update cached allowlist
-    end
-```
-
-### Phase 1: Campaign Planning
-
-During campaign setup, the orchestrator creates property lists on governance agents with filters and brand manifests. The governance agent evaluates properties and returns a **pass/fail list of identifiers** (no raw scores are exposed). The orchestrator shares the `list_id` and `auth_token` with the decisioning platform, which fetches and caches the resolved list.
-
-### Phase 2: Bid Time
-
-At bid time, the decisioning platform uses **only its local cache**—no calls to governance agents. Latency requirements (under 100ms) make real-time API calls impractical. The decisioning platform may implement this cache as:
-
-- **Direct domain lookup**: In-memory set of approved domains
-- **AXE segments**: Cache domains as `axei` (include) or `axex` (exclude) segments for impression-level filtering
-
-The choice of caching mechanism is implementation-specific; the protocol only requires that bid-time decisions use cached data.
-
-### Phase 3: Monitoring
+### The Complete Flow
 
-During campaign flight, governance agents continue evaluating properties. When a property's compliance status changes, the agent sends a webhook notification to registered subscribers. The webhook contains **change counts only** (not scores or reasons)—the decisioning platform must call `get_property_list` to fetch the updated list and refresh its cache.
+1. **Publisher declares** properties, sales agents, AND governance agents in `adagents.json`
+2. **Buyer discovers** governance agents by reading `property_features` from adagents.json
+3. **Buyer queries** each governance agent's `list_property_features` for detailed capabilities
+4. **Buyer creates** property lists on each governance agent with filters and brand manifests
+5. **Governance agents evaluate** properties and notify buyer via webhooks when lists change
+6. **Buyer aggregates** results into a final compliant list
+7. **Buyer shares** property list reference with sellers (with auth token)
+8. **Seller caches** resolved list for bid-time decisions
 
 ## Sharing Property Lists with Sellers
 
@@ -251,31 +248,34 @@ Both protocols operate on properties but serve different purposes:
 
 ### Discovery
 
-- **[list_property_features](./tasks/list_property_features)**: Discover what data a governance agent can provide about properties
+- **[list_property_features](/docs/governance/property/tasks/list_property_features)**: Discover what data a governance agent can provide about properties
 
 ### Property List Management
 
-- **[create_property_list](./tasks/property_lists#create_property_list)**: Create a new property list on a governance agent
-- **[get_property_list](./tasks/property_lists#get_property_list)**: Retrieve resolved properties (with caching guidance)
-- **[update_property_list](./tasks/property_lists#update_property_list)**: Modify filters or base properties
-- **[delete_property_list](./tasks/property_lists#delete_property_list)**: Remove a property list
+- **[create_property_list](/docs/governance/property/tasks/property_lists#create_property_list)**: Create a new property list on a governance agent
+- **[get_property_list](/docs/governance/property/tasks/property_lists#get_property_list)**: Retrieve resolved properties (with caching guidance)
+- **[update_property_list](/docs/governance/property/tasks/property_lists#update_property_list)**: Modify filters or base properties
+- **[delete_property_list](/docs/governance/property/tasks/property_lists#delete_property_list)**: Remove a property list
 
 ## Getting Started
 
 **Publishers:**
 1. Create `/.well-known/adagents.json` with property definitions
 2. Authorize sales agents for your properties
+3. Declare governance agents in `property_features` (Scope3 for carbon, OneTrust for consent, TAG for certification, etc.)
 
 **Buyers:**
-1. Subscribe to governance agents for property data
-2. Create property lists on each governance agent with filters and brand manifests
-3. Aggregate results into a final compliant list
-4. Share property list references with sellers (with auth tokens)
+1. Discover governance agents by reading `property_features` from publishers' adagents.json files
+2. Query each governance agent's `list_property_features` for capabilities
+3. Create property lists on relevant governance agents with filters and brand manifests
+4. Aggregate results into a final compliant list
+5. Share property list references with sellers (with auth tokens)
 
 **Governance Agent Implementers:**
 1. Implement `list_property_features` to advertise your capabilities
 2. Implement property list CRUD operations
 3. Support webhooks to notify buyers when evaluations change
-4. See the [Protocol Specification](./specification) for implementation details
+4. Work with publishers to get listed in their `property_features`
+5. See the [Protocol Specification](/docs/governance/property/specification) for implementation details
 
-See the [Protocol Specification](./specification) for detailed implementation guidance.
+See the [Protocol Specification](/docs/governance/property/specification) for detailed implementation guidance.