feat: align with signals agent spec and add get_signals endpoint

CLAUDE.md

@@ -86,7 +86,7 @@ Implementation details can be mentioned as:
 5. **AI-Optimized**: Designed for AI agents
 
 ### What Exists vs What Doesn't
-- ✅ `list_products` - discovers inventory
+- ✅ `get_products` - discovers inventory
 - ❌ `discover_products` - doesn't exist
 - ❌ `get_avails` - removed in favor of direct purchase
 - ✅ `create_media_buy` - creates campaigns

docs/media-buy/api-reference.md

@@ -142,6 +142,7 @@ Creates a media buy from selected packages.
     "geo_country_any_of": ["US"],
     "geo_region_any_of": ["CA", "NY"],
     "audience_segment_any_of": ["3p:pet_owners"],
+    "signals": ["auto_intenders_q1_2025"],  // Optional: Signal IDs from get_signals
     "frequency_cap": {
       "suppress_minutes": 30,
       "scope": "media_buy"
@@ -671,7 +672,7 @@ Retrieves delivery data for all active media buys across all principals.
 
 **Response:** Same format as get_media_buy_delivery but includes all media buys.
 
-### 16. list_products
+### 16. get_products
 
 Lists available advertising products for the authenticated principal with optional natural language brief and filtering.
 
@@ -797,12 +798,30 @@ Verify if required AEE dimensions are supported for a channel.
 
 Use this before creating a media buy to ensure the publisher can provide required AEE signals.
 
+### 19. get_signals (Optional)
+
+Publishers may optionally implement the `get_signals` endpoint from the [Signals Discovery Protocol](../../signals-protocol-v1.md#get_signals) to advertise available signals for targeting.
+
+**Purpose:** Allows buyers to discover what signals (audiences, contextual, geographic, etc.) are available through the publisher's data partnerships.
+
+**Implementation:** See the [Signals Discovery Protocol specification](../../signals-protocol-v1.md#get_signals) for the complete interface definition.
+
+**Integration with Media Buy:**
+- The signal IDs returned by `get_signals` can be used in the `targeting.signals` array when creating a media buy
+- Publishers implementing this endpoint should ensure the audience IDs are compatible with their targeting systems
+- Cost information in the response helps buyers understand incremental data costs
+
+**Notes:**
+- This is an optional endpoint - publishers may choose to expose all, some, or no signals
+- The protocol supports various audience types: owned, marketplace, and destination audiences
+- Publishers should coordinate with their data providers on which segments to expose
+
 
 ## Creative Macro Signal
 
-The creative macro is a third type of provided signal from AEE, enabling dynamic creative customization.
+The creative macro is a third type of AEE signal, enabling dynamic creative customization.
 
-### AEE Provided Signals
+### AEE Signals
 
 1. **may_include** - Signals to include for targeting
 2. **must_exclude** - Signals that must be excluded  
@@ -824,7 +843,7 @@ The AEE can then provide a creative_macro string in its response:
 {
   "should_bid": true,
   "bid_price": 5.50,
-  "provided_signals": {
+  "aee_signals": {
     "may_include": ["sports", "premium_user"],
     "must_exclude": ["competitor_xyz"],
     "creative_macro": "city:San Francisco|weather:sunny|segment:tech_professional"
@@ -1136,6 +1155,9 @@ interface Targeting {
   audience_segment_any_of?: string[];    // ["1p:loyalty", "3p:auto_intenders"]
   audience_segment_none_of?: string[];
 
+  // Signal-based targeting (from get_signals)
+  signals?: string[];                    // ["auto_intenders_q1_2025", "high_income_households"]
+
   // Media type targeting
   media_type_any_of?: string[];          // ["video", "audio", "display", "native"]
   media_type_none_of?: string[];

docs/media-buy/product-discovery.md

@@ -6,13 +6,13 @@ title: Product Discovery
 
 Product discovery is the foundation of the Media Buy Protocol, enabling AI agents to find relevant advertising inventory using natural language. This document explains the discovery lifecycle and how to implement the discovery tools.
 
-## The Discovery Tool: `list_products`
+## The Discovery Tool: `get_products`
 
 AdCP provides a single discovery tool that uses natural language to find relevant advertising inventory.
 
 ### How it Works
 
-The `list_products` tool accepts a natural language brief and optional format filters to return matching products from the catalog. If no brief is provided, it returns all available products for the authenticated principal.
+The `get_products` tool accepts a natural language brief and optional format filters to return matching products from the catalog. If no brief is provided, it returns all available products for the authenticated principal.
 
 **Request Options:**
 
@@ -85,11 +85,11 @@ def get_product_catalog():
 
 ### Step 2: Implement Natural Language Processing
 
-The `list_products` tool needs to interpret natural language briefs:
+The `get_products` tool needs to interpret natural language briefs:
 
 ```python
 @mcp.tool
-def list_products(req: ListProductsRequest, context: Context) -> ListProductsResponse:
+def get_products(req: GetProductsRequest, context: Context) -> GetProductsResponse:
     # Authenticate principal
     principal_id = _get_principal_id_from_context(context)
 
@@ -203,7 +203,7 @@ The complete discovery workflow with format awareness:
 graph TD
     A[list_creative_formats] --> B[Identify available formats]
     B --> C[User provides brief + format filters]
-    C --> D[list_products]
+    C --> D[get_products]
     D --> E{Products found?}
     E -->|Yes| F[Review products]
     E -->|No| G[Generate custom products]
@@ -230,7 +230,7 @@ Use format knowledge to filter products:
 
 ```javascript
 // Only discover products that accept standard audio formats
-const products = await client.call_tool("list_products", {
+const products = await client.call_tool("get_products", {
   brief: "Reach young adults interested in gaming",
   format_types: ["audio"],
   standard_formats_only: true
@@ -310,7 +310,7 @@ Common error scenarios and handling:
 
 ```python
 @mcp.tool
-def list_products(req: ListProductsRequest, context: Context) -> ListProductsResponse:
+def get_products(req: GetProductsRequest, context: Context) -> GetProductsResponse:
     try:
         principal_id = _get_principal_id_from_context(context)
     except:
@@ -342,7 +342,7 @@ test_briefs = [
 ]
 
 for brief in test_briefs:
-    result = list_products(ListProductsRequest(brief=brief), context)
+    result = get_products(GetProductsRequest(brief=brief), context)
     assert len(result.products) > 0
     print(f"Brief: {brief} -> Found {len(result.products)} products")
 ```
@@ -351,7 +351,7 @@ for brief in test_briefs:
 
 Discovery is just the first step. Ensure smooth transitions to the next phases:
 
-1. **Discovery** → `list_products` finds relevant inventory
+1. **Discovery** → `get_products` finds relevant inventory
 2. **Purchase** → `create_media_buy` executes the campaign
 4. **Creative** → `add_creative_assets` uploads assets
 5. **Monitor** → Track delivery and optimize

signals-protocol-v1.md

@@ -73,9 +73,9 @@ Each MCP session is authenticated as one of:
 
 ## Protocol Specification
 
-### get_audiences
+### get_signals
 
-Discovers relevant audiences based on a marketing specification.
+Discovers relevant signals (audiences, contextual, geographic, etc.) based on a marketing specification.
 
 #### Request
 
@@ -141,7 +141,7 @@ Activates an audience for use on a specific platform/seat.
 
 ```json
 {
-  "segment_id": "string",  // From get_audiences (required)
+  "segment_id": "string",  // From get_signals (required)
   "platform": "string",    // Required
   "seat": "string",        // Optional
   "options": {
@@ -264,7 +264,7 @@ Reports usage data for billing reconciliation.
 
 ## Typical Flow
 
-1. **Discovery**: Use `get_audiences` to find relevant audiences
+1. **Discovery**: Use `get_signals` to find relevant signals
 2. **Review**: Check `deployment.is_live` status
 3. **Activate**: If not live, use `activate_audience`
 4. **Monitor**: Use `check_audience_status` to track activation