fix(acp): include MCP toolsets in ACP sessions

acp_adapter/server.py

@@ -60,7 +60,7 @@ from acp_adapter.events import (
     make_tool_progress_cb,
 )
 from acp_adapter.permissions import make_approval_callback
-from acp_adapter.session import SessionManager, SessionState
+from acp_adapter.session import SessionManager, SessionState, _expand_acp_enabled_toolsets
 
 logger = logging.getLogger(__name__)
 
@@ -287,7 +287,11 @@ class HermesACPAgent(acp.Agent):
         try:
             from model_tools import get_tool_definitions
 
-            enabled_toolsets = getattr(state.agent, "enabled_toolsets", None) or ["hermes-acp"]
+            enabled_toolsets = _expand_acp_enabled_toolsets(
+                getattr(state.agent, "enabled_toolsets", None) or ["hermes-acp"],
+                mcp_server_names=[server.name for server in mcp_servers],
+            )
+            state.agent.enabled_toolsets = enabled_toolsets
             disabled_toolsets = getattr(state.agent, "disabled_toolsets", None)
             state.agent.tools = get_tool_definitions(
                 enabled_toolsets=enabled_toolsets,
@@ -754,7 +758,9 @@ class HermesACPAgent(acp.Agent):
     def _cmd_tools(self, args: str, state: SessionState) -> str:
         try:
             from model_tools import get_tool_definitions
-            toolsets = getattr(state.agent, "enabled_toolsets", None) or ["hermes-acp"]
+            toolsets = _expand_acp_enabled_toolsets(
+                getattr(state.agent, "enabled_toolsets", None) or ["hermes-acp"]
+            )
             tools = get_tool_definitions(enabled_toolsets=toolsets, quiet_mode=True)
             if not tools:
                 return "No tools available."

acp_adapter/session.py

@@ -106,6 +106,24 @@ def _register_task_cwd(task_id: str, cwd: str) -> None:
         logger.debug("Failed to register ACP task cwd override", exc_info=True)
 
 
+def _expand_acp_enabled_toolsets(
+    toolsets: List[str] | None = None,
+    mcp_server_names: List[str] | None = None,
+) -> List[str]:
+    """Return ACP toolsets plus explicit MCP server toolsets for this session."""
+    expanded: List[str] = []
+    for name in list(toolsets or ["hermes-acp"]):
+        if name and name not in expanded:
+            expanded.append(name)
+
+    for server_name in list(mcp_server_names or []):
+        toolset_name = f"mcp-{server_name}"
+        if server_name and toolset_name not in expanded:
+            expanded.append(toolset_name)
+
+    return expanded
+
+
 def _clear_task_cwd(task_id: str) -> None:
     """Remove task-specific cwd overrides for an ACP session."""
     if not task_id:
@@ -537,9 +555,18 @@ class SessionManager:
         elif isinstance(model_cfg, str) and model_cfg.strip():
             default_model = model_cfg.strip()
 
+        configured_mcp_servers = [
+            name
+            for name, cfg in (config.get("mcp_servers") or {}).items()
+            if not isinstance(cfg, dict) or cfg.get("enabled", True) is not False
+        ]
+
         kwargs = {
             "platform": "acp",
-            "enabled_toolsets": ["hermes-acp"],
+            "enabled_toolsets": _expand_acp_enabled_toolsets(
+                ["hermes-acp"],
+                mcp_server_names=configured_mcp_servers,
+            ),
             "quiet_mode": True,
             "session_id": session_id,
             "model": model or default_model,

tests/acp/test_server.py

@@ -904,9 +904,15 @@ class TestRegisterSessionMcpServers:
         ]
 
         with patch("tools.mcp_tool.register_mcp_servers", return_value=["mcp_srv_search"]), \
-             patch("model_tools.get_tool_definitions", return_value=fake_tools):
+             patch("model_tools.get_tool_definitions", return_value=fake_tools) as mock_defs:
             await agent._register_session_mcp_servers(state, [server])
 
+        mock_defs.assert_called_once_with(
+            enabled_toolsets=["hermes-acp", "mcp-srv"],
+            disabled_toolsets=None,
+            quiet_mode=True,
+        )
+        assert state.agent.enabled_toolsets == ["hermes-acp", "mcp-srv"]
         assert state.agent.tools == fake_tools
         assert state.agent.valid_tool_names == {"mcp_srv_search", "terminal"}
         # _invalidate_system_prompt should have been called

tests/acp/test_session.py

@@ -138,6 +138,43 @@ class TestListAndCleanup:
 class TestPersistence:
     """Verify that sessions are persisted to SessionDB and can be restored."""
 
+    def test_create_session_includes_registered_mcp_toolsets(self, tmp_path, monkeypatch):
+        captured = {}
+
+        def fake_resolve_runtime_provider(requested=None, **kwargs):
+            return {
+                "provider": "openrouter",
+                "api_mode": "chat_completions",
+                "base_url": "https://openrouter.example/v1",
+                "api_key": "***",
+                "command": None,
+                "args": [],
+            }
+
+        def fake_agent(**kwargs):
+            captured.update(kwargs)
+            return SimpleNamespace(model=kwargs.get("model"), enabled_toolsets=kwargs.get("enabled_toolsets"))
+
+        monkeypatch.setattr("hermes_cli.config.load_config", lambda: {
+            "model": {"provider": "openrouter", "default": "test-model"},
+            "mcp_servers": {
+                "olympus": {"command": "python", "enabled": True},
+                "exa": {"url": "https://exa.ai/mcp"},
+                "disabled": {"command": "python", "enabled": False},
+            },
+        })
+        monkeypatch.setattr(
+            "hermes_cli.runtime_provider.resolve_runtime_provider",
+            fake_resolve_runtime_provider,
+        )
+        db = SessionDB(tmp_path / "state.db")
+
+        with patch("run_agent.AIAgent", side_effect=fake_agent):
+            manager = SessionManager(db=db)
+            manager.create_session(cwd="/work")
+
+        assert captured["enabled_toolsets"] == ["hermes-acp", "mcp-olympus", "mcp-exa"]
+
     def test_create_session_writes_to_db(self, manager):
         state = manager.create_session(cwd="/project")
         db = manager._get_db()