Limit exposed tools to the ones not excluded by the (fixed) agent context

src/serena/agent.py

@@ -769,10 +769,20 @@ class SerenaAgent:
                 )
                 Logger.root.addHandler(self._gui_log_handler)
 
+        # set the agent context
+        if context is None:
+            context = SerenaAgentContext.load_default()
+        self._context = context
+
         # instantiate all tool classes
         self._all_tools: dict[type[Tool], Tool] = {tool_class: tool_class(self) for tool_class in ToolRegistry.get_all_tool_classes()}
         tool_names = [tool.get_name_from_cls() for tool in self._all_tools.values()]
 
+        # determine the set exposed tools (which e.g. the MCP shall see), limited by the context
+        # (which is fixed for the session)
+        excluded_tool_classes = set(self._context.get_excluded_tool_classes())
+        self._exposed_tools = {tc: t for tc, t in self._all_tools.items() if tc not in excluded_tool_classes}
+
         # If GUI log window is enabled, set the tool names for highlighting
         if self._gui_log_handler is not None:
             self._gui_log_handler.log_viewer.set_tool_names(tool_names)
@@ -807,14 +817,14 @@ class SerenaAgent:
         self.ignore_spec: PathSpec  # not set to None to avoid assert statements
         """Ignore spec, extracted from the project's gitignore files and the explicitly configured ignored paths."""
 
-        # Apply context and mode tool configurations
-        if context is None:
-            context = SerenaAgentContext.load_default()
+        # set the active modes
         if modes is None:
             modes = SerenaAgentMode.load_default_modes()
-        self._context = context
         self._modes = modes
+
+        # log tool information
         log.info(f"Loaded tools ({len(self._all_tools)}): {', '.join([tool.get_name_from_cls() for tool in self._all_tools.values()])}")
+        log.info(f"Number of exposed tools given {self._context}: {len(self._exposed_tools)}")
 
         self._active_tools: dict[type[Tool], Tool] = {}
         self._update_active_tools()
@@ -880,11 +890,14 @@ class SerenaAgent:
 
     def get_exposed_tool_instances(self) -> list["Tool"]:
         """
-        :return: all tool instances, including the non-active ones. For MCP clients, we need to expose them all since typical
-            clients don't react to changes in the set of tools.
-            An attempt to use a non-active tool will result in an error.
+        :return: the tool instances which are exposed (e.g. to the MCP client).
+            Note that the set of exposed tools is fixed for the session, as
+            clients don't react to changes in the set of tools, so this is the superset
+            of tools that can be offered during the session.
+            If a client should attempt to use a tool that is dynamically disabled
+            (e.g. because a project is activated that disables it), it will receive an error.
         """
-        return list(self._all_tools.values())
+        return list(self._exposed_tools.values())
 
     def get_active_project(self) -> Project | None:
         """

src/serena/config.py

@@ -11,6 +11,7 @@ from typing import TYPE_CHECKING, Self
 
 import yaml
 from sensai.util import logging
+from sensai.util.string import ToStringMixin
 
 from serena.constants import CONTEXT_YAMLS_DIR, DEFAULT_CONTEXT, DEFAULT_MODES, MODE_YAMLS_DIR
 
@@ -93,7 +94,7 @@ class SerenaAgentMode:
 
 
 @dataclass
-class SerenaAgentContext:
+class SerenaAgentContext(ToStringMixin):
     """Represents a context where the agent is operating (an IDE, a chat, etc.), typically read off a YAML file.
     An agent can only be in a single context at a time.
     The contexts cannot be changed after the agent is running.
@@ -104,6 +105,9 @@ class SerenaAgentContext:
     description: str = ""
     excluded_tools: set[str] = field(default_factory=set)
 
+    def _tostring_includes(self) -> list[str]:
+        return ["name"]
+
     def to_json_dict(self) -> dict[str, str | list[str]]:
         result = asdict(self)
         result["excluded_tools"] = list(result["excluded_tools"])