feat: add reference creative agent helper

Added pre-configured creative_agent for easy access to the reference
creative agent at creative.adcontextprotocol.org/mcp. This provides
instant access to creative preview functionality without authentication.

Features:
- creative_agent: Pre-configured ADCPClient for creative operations
- CREATIVE_AGENT_CONFIG: Exported configuration constant
- No authentication required
- Perfect for testing preview_creative and list_creative_formats

Added 3 new tests for creative agent functionality and updated
README with creative agent examples.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: bokelley

README.md

@@ -47,6 +47,7 @@ if result.success:
 Test helpers include:
 - **`test_agent`**: Pre-configured MCP test agent (ready to use)
 - **`test_agent_a2a`**: Pre-configured A2A test agent
+- **`creative_agent`**: Reference creative agent for preview functionality
 - **`test_agent_client`**: Multi-agent client with both protocols
 - **`create_test_agent()`**: Factory for custom test configurations
 
@@ -112,8 +113,8 @@ async with ADCPMultiAgentClient(
 Pre-configured test agents for instant prototyping and testing:
 
 ```python
-from adcp.testing import test_agent, test_agent_a2a, test_agent_client, create_test_agent
-from adcp.types.generated import GetProductsRequest
+from adcp.testing import test_agent, test_agent_a2a, creative_agent, test_agent_client, create_test_agent
+from adcp.types.generated import GetProductsRequest, PreviewCreativeRequest
 
 # 1. Single agent (MCP)
 result = await test_agent.get_products(
@@ -125,14 +126,21 @@ result = await test_agent_a2a.get_products(
     GetProductsRequest(brief="Coffee brands")
 )
 
-# 3. Multi-agent (parallel execution)
+# 3. Creative agent (preview functionality)
+result = await creative_agent.preview_creative(
+    PreviewCreativeRequest(
+        manifest={"format_id": "banner_300x250", "assets": {...}}
+    )
+)
+
+# 4. Multi-agent (parallel execution)
 results = await test_agent_client.get_products(
     GetProductsRequest(brief="Coffee brands")
 )
 
-# 4. Custom configuration
+# 5. Custom configuration
 from adcp.client import ADCPClient
-config = create_test_agent(id="my-test", name="My Test Agent")
+config = create_test_agent(id="my-test", timeout=60.0)
 client = ADCPClient(config)
 ```
 

src/adcp/__init__.py

@@ -21,10 +21,12 @@
 
 # Test helpers
 from adcp.testing import (
+    CREATIVE_AGENT_CONFIG,
     TEST_AGENT_A2A_CONFIG,
     TEST_AGENT_MCP_CONFIG,
     TEST_AGENT_TOKEN,
     create_test_agent,
+    creative_agent,
     test_agent,
     test_agent_a2a,
     test_agent_client,
@@ -159,11 +161,13 @@
     # Test helpers
     "test_agent",
     "test_agent_a2a",
+    "creative_agent",
     "test_agent_client",
     "create_test_agent",
     "TEST_AGENT_TOKEN",
     "TEST_AGENT_MCP_CONFIG",
     "TEST_AGENT_A2A_CONFIG",
+    "CREATIVE_AGENT_CONFIG",
     # Exceptions
     "ADCPError",
     "ADCPConnectionError",

src/adcp/testing/__init__.py

@@ -6,10 +6,12 @@
 from __future__ import annotations
 
 from adcp.testing.test_helpers import (
+    CREATIVE_AGENT_CONFIG,
     TEST_AGENT_A2A_CONFIG,
     TEST_AGENT_MCP_CONFIG,
     TEST_AGENT_TOKEN,
     create_test_agent,
+    creative_agent,
     test_agent,
     test_agent_a2a,
     test_agent_client,
@@ -18,9 +20,11 @@
 __all__ = [
     "test_agent",
     "test_agent_a2a",
+    "creative_agent",
     "test_agent_client",
     "create_test_agent",
     "TEST_AGENT_TOKEN",
     "TEST_AGENT_MCP_CONFIG",
     "TEST_AGENT_A2A_CONFIG",
+    "CREATIVE_AGENT_CONFIG",
 ]

src/adcp/testing/test_helpers.py

@@ -30,6 +30,14 @@
     auth_token=TEST_AGENT_TOKEN,
 )
 
+# Reference creative agent configuration - MCP protocol
+# No authentication required for the reference creative agent
+CREATIVE_AGENT_CONFIG = AgentConfig(
+    id="creative-agent",
+    agent_uri="https://creative.adcontextprotocol.org/mcp",
+    protocol=Protocol.MCP,
+)
+
 
 def _create_test_agent_client() -> ADCPClient:
     """Create pre-configured test agent client using MCP protocol.
@@ -59,6 +67,19 @@ def _create_test_agent_a2a_client() -> ADCPClient:
     return ADCPClient(TEST_AGENT_A2A_CONFIG)
 
 
+def _create_creative_agent_client() -> ADCPClient:
+    """Create pre-configured creative agent client.
+
+    Returns:
+        ADCPClient instance configured for the reference creative agent
+
+    Note:
+        The reference creative agent is public and requires no authentication.
+        It provides creative preview functionality for testing and examples.
+    """
+    return ADCPClient(CREATIVE_AGENT_CONFIG)
+
+
 def _create_test_multi_agent_client() -> ADCPMultiAgentClient:
     """Create multi-agent client with both test agents configured.
 
@@ -118,6 +139,29 @@ def _create_test_multi_agent_client() -> ADCPMultiAgentClient:
 #     DO NOT use in production applications.
 test_agent_a2a: ADCPClient = _create_test_agent_a2a_client()
 
+# Pre-configured reference creative agent.
+# Provides creative preview functionality without authentication.
+#
+# Example:
+#     ```python
+#     from adcp.testing import creative_agent
+#     from adcp.types.generated import PreviewCreativeRequest
+#
+#     result = await creative_agent.preview_creative(
+#         PreviewCreativeRequest(
+#             manifest={
+#                 "format_id": "banner_300x250",
+#                 "assets": {...}
+#             }
+#         )
+#     )
+#     ```
+#
+# Note:
+#     The reference creative agent is public and requires no authentication.
+#     Perfect for testing creative rendering and preview functionality.
+creative_agent: ADCPClient = _create_creative_agent_client()
+
 # Multi-agent client with both test agents configured.
 # Useful for testing multi-agent patterns and protocol comparisons.
 #

tests/test_helpers.py

@@ -4,10 +4,12 @@
 
 from adcp.client import ADCPClient, ADCPMultiAgentClient
 from adcp.testing import (
+    CREATIVE_AGENT_CONFIG,
     TEST_AGENT_A2A_CONFIG,
     TEST_AGENT_MCP_CONFIG,
     TEST_AGENT_TOKEN,
     create_test_agent,
+    creative_agent,
     test_agent,
     test_agent_a2a,
     test_agent_client,
@@ -151,3 +153,27 @@ def test_agent_ids_in_test_agent_client():
     agent_ids = test_agent_client.agent_ids
     assert "test-agent-mcp" in agent_ids
     assert "test-agent-a2a" in agent_ids
+
+
+def test_creative_agent_config_structure():
+    """Test CREATIVE_AGENT_CONFIG has correct structure."""
+    assert CREATIVE_AGENT_CONFIG.id == "creative-agent"
+    assert CREATIVE_AGENT_CONFIG.protocol == Protocol.MCP
+    assert CREATIVE_AGENT_CONFIG.agent_uri == "https://creative.adcontextprotocol.org/mcp"
+    # Creative agent requires no authentication
+    assert CREATIVE_AGENT_CONFIG.auth_token is None
+
+
+def test_creative_agent_is_adcp_client():
+    """Test that creative_agent is an ADCPClient instance."""
+    assert isinstance(creative_agent, ADCPClient)
+    assert hasattr(creative_agent, "preview_creative")
+    assert hasattr(creative_agent, "list_creative_formats")
+    assert callable(creative_agent.preview_creative)
+    assert callable(creative_agent.list_creative_formats)
+
+
+def test_creative_agent_config_match():
+    """Test that creative_agent uses CREATIVE_AGENT_CONFIG."""
+    assert creative_agent.agent_config.id == CREATIVE_AGENT_CONFIG.id
+    assert creative_agent.agent_config.protocol == CREATIVE_AGENT_CONFIG.protocol