fix: correct registry URL, MCP media type, and broken links

- Default registry URL: evalstate-hf-discover.hf.space is dead (404),
  replaced with huggingface-hf-discover.hf.space (the official HF
  Discover space, confirmed working via /health and /search endpoints).

- MCP media type: the canonical type used by hf-discover is
  application/mcp-server-card+json (application/mcp-server+json is a
  legacy alias). Updated the README table and test assertions to match
  the code which already used the correct canonical type.

- Broken GitHub links in References sections:
  - nichochar/ard-spec -> ards-project/ard-spec (repo moved)
  - nichochar/ai-catalog removed (repo no longer exists)
  - a2aproject/a2a-spec -> google/A2A (repo moved/renamed)

- Added agenticresourcediscovery.org as the official ARD docs link in
  both READMEs, per the ARD project's current home.

Author: Scion Agent

contributing/samples/ardhf/README.md

@@ -3,7 +3,7 @@
 ## Overview
 
 ARDHF wraps [HuggingFace Discover](https://github.com/huggingface/hf-discover)
-(ARD — Agentic Resource Discovery) as an ADK `BaseToolset`.  It gives any ADK
+([ARD](https://agenticresourcediscovery.org) — Agentic Resource Discovery) as an ADK `BaseToolset`.  It gives any ADK
 agent the ability to **discover, inspect, and connect to** agents, skills,
 MCP servers, HuggingFace Spaces, and other agentic resources at runtime.
 
@@ -50,7 +50,7 @@ tools automatically.
 | `search_ards` | Search ARD registries across all artifact types (agents, skills, MCP servers, Spaces) |
 | `search_agents` | Search filtered to A2A agents (`application/a2a-agent-card+json`) |
 | `search_skills` | Search filtered to skills (`application/ai-skill`) |
-| `search_tools` | Search filtered to MCP servers (`application/mcp-server+json`) |
+| `search_tools` | Search filtered to MCP servers (`application/mcp-server-card+json`) |
 | `search_spaces` | Search filtered to HuggingFace Spaces (`application/vnd.huggingface.space+json`) |
 | `get_agent_card` | Fetch a specific artifact (agent card, skill markdown, MCP descriptor) by URL |
 | `connect_agent` | Send a message to a remote A2A agent — may return an immediate response or start a long-running task with its own lifecycle |
@@ -241,7 +241,7 @@ Use multiple toolset instances to search different registries:
 
 ```python
 hf_toolset = AgentFinderToolset(
-    registry_url="https://evalstate-hf-discover.hf.space",
+    registry_url="https://huggingface-hf-discover.hf.space",
     tool_name_prefix="hf",
 )
 internal_toolset = AgentFinderToolset(
@@ -300,8 +300,8 @@ pytest tests/unittests/tools/ardhf/ -v
 
 ## References
 
-- [ARD Specification](https://github.com/nichochar/ard-spec) — Agentic Resource Discovery specification
+- [ARD — Agentic Resource Discovery](https://agenticresourcediscovery.org) — Official ARD specification and documentation
+- [ARD Specification (GitHub)](https://github.com/ards-project/ard-spec) — ARD spec repository
 - [HuggingFace Discover](https://github.com/huggingface/hf-discover) — ARD reference implementation
-- [ai-catalog](https://github.com/nichochar/ai-catalog) — Curated agentic resource catalog
 - [ADK Documentation](https://google.github.io/adk-docs/) — Google Agent Development Kit
-- [A2A Protocol](https://github.com/a2aproject/a2a-spec) — Agent-to-Agent protocol specification
+- [A2A Protocol](https://github.com/google/A2A) — Agent-to-Agent protocol specification

contributing/samples/ardhf/agent.py

@@ -45,7 +45,7 @@
 
 _registry_url = os.environ.get(
     "ARDHF_REGISTRY_URL",
-    "https://evalstate-hf-discover.hf.space",
+    "https://huggingface-hf-discover.hf.space",
 )
 _local = os.environ.get("ARDHF_LOCAL", "").lower() in (
     "1",

contributing/samples/ardhf_dynamic_agents/README.md

@@ -115,5 +115,6 @@ User
 ## Related
 
 - [ARDHF basic sample](../ardhf/) — Simpler sample focusing on discovery only.
+- [ARD — Agentic Resource Discovery](https://agenticresourcediscovery.org) — Official ARD specification and documentation.
 - [HuggingFace Discover](https://github.com/huggingface/hf-discover) — ARD reference implementation.
-- [A2A Protocol](https://github.com/a2aproject/a2a-spec) — Agent-to-Agent protocol specification.
+- [A2A Protocol](https://github.com/google/A2A) — Agent-to-Agent protocol specification.

contributing/samples/ardhf_dynamic_agents/agent.py

@@ -52,7 +52,7 @@
 
 _registry_url = os.environ.get(
     "ARDHF_REGISTRY_URL",
-    "https://evalstate-hf-discover.hf.space",
+    "https://huggingface-hf-discover.hf.space",
 )
 _token = os.environ.get("HF_TOKEN")
 

src/google/adk_community/tools/ardhf/ardhf_toolset.py

@@ -58,7 +58,7 @@
 logger = logging.getLogger(__name__)
 
 # Default hosted HuggingFace Discover registry.
-_DEFAULT_REGISTRY_URL = "https://evalstate-hf-discover.hf.space"
+_DEFAULT_REGISTRY_URL = "https://huggingface-hf-discover.hf.space"
 
 # HTTP timeout for remote requests (seconds).
 _HTTP_TIMEOUT = 30

tests/unittests/tools/ardhf/test_ardhf_toolset.py

@@ -86,7 +86,7 @@ def test_skill_kind(self):
   def test_mcp_kind(self):
     assert (
         _artifact_type_for_kind("mcp")
-        == "application/mcp-server+json"
+        == "application/mcp-server-card+json"
     )
 
   def test_space_kind(self):
@@ -655,12 +655,12 @@ def test_search_with_mcp_filter(self):
     response = _remote_search(
         CHALLENGE_URL,
         "find tools",
-        artifact_type="application/mcp-server+json",
+        artifact_type="application/mcp-server-card+json",
         limit=10,
     )
 
     for result in response["results"]:
-      assert result["type"] == "application/mcp-server+json"
+      assert result["type"] == "application/mcp-server-card+json"
 
   def test_search_with_skill_filter(self):
     """Filtering by skill type returns only skill results."""
@@ -822,4 +822,4 @@ async def test_search_ards_with_kind_resolution(self):
 
     assert "results" in result
     for entry in result["results"]:
-      assert entry["type"] == "application/mcp-server+json"
+      assert entry["type"] == "application/mcp-server-card+json"