fix(skills): read MCP server registry live to avoid stale STRICT gate

CapabilityValidator cached the MCP server snapshot once, so servers that
connected after the first validation stayed invisible under STRICT
enforcement. Read the process-level registry live each call (cheap
set-copy under lock); tool cache is unchanged. (#3307)

Co-authored-by: Mervin Praison <MervinPraison@users.noreply.github.com>

Author: praisonai-triage-agent[bot]

src/praisonai-agents/praisonaiagents/skills/capability_validator.py

@@ -203,22 +203,21 @@ def _get_available_tools(self) -> Set[str]:
         return self._tool_cache
 
     def _get_available_servers(self) -> Set[str]:
-        """Get set of available MCP server names.
+        """Get set of available MCP server names from the active MCP registry.
 
         Derives names from the MCP client registry of servers that have been
         namespaced (via ``with_tool_prefix``) in this process. Without this an
         MCP-server-gated skill could never pass STRICT validation because the
         set was always empty (issue #3307).
 
-        Queried live (not cached) because MCP servers register lazily: a skill
-        may be validated before its required server connects. Caching the first
-        empty snapshot would leave STRICT validation permanently reporting the
-        skill unavailable even after the server registers. The registry read is
-        just a cheap ``set`` copy, so there is no hot-path cost.
+        The MCP registry is populated dynamically as servers connect during a
+        run, so this is read live (not cached) to avoid a stale snapshot that
+        would keep rejecting servers registered after the first validation.
+        The read is a cheap set copy under a lock, so there is no hot-path cost.
         """
         try:
             from ..mcp.mcp import MCP
-            return MCP.list_active_server_names()
+            return set(MCP.list_active_server_names())
         except ImportError:
             logger.debug("MCP not available")
             return set()

src/praisonai-agents/tests/unit/skills/test_capability_validator.py

@@ -269,6 +269,25 @@ def test_available_servers_read_from_mcp_registry(self):
             servers = validator._get_available_servers()
         assert "filesystem" in servers
 
+    def test_available_servers_read_live_not_cached(self):
+        """Issue #3307 Gap 3: server availability must not be cached stale.
+
+        The MCP registry fills in as servers connect during a run, so a server
+        registered after the first validation must become visible without an
+        explicit clear_cache() call.
+        """
+        validator = CapabilityValidator(EnforcementLevel.STRICT)
+        with patch(
+            "praisonaiagents.mcp.mcp.MCP.list_active_server_names",
+            return_value=set(),
+        ):
+            assert validator._get_available_servers() == set()
+        with patch(
+            "praisonaiagents.mcp.mcp.MCP.list_active_server_names",
+            return_value={"filesystem"},
+        ):
+            assert "filesystem" in validator._get_available_servers()
+
     def test_mcp_gated_skill_passes_strict_when_server_active(self):
         """Issue #3307 Gap 3: an MCP-server-gated skill can now pass STRICT."""
         requirements = SkillRequirements(servers=["filesystem"])