Hooks: handle tool_input passed as string gracefully instead of failing

Copilot CLI sends strings

CHANGELOG.md

@@ -66,6 +66,9 @@ Status of the `main` branch. Changes prior to the next official version change w
   - Tray manager: Add NixOS-support for AppIndicator-based trays (e.g., most Wayland-trays) to the package in flake.nix.
   - Fix: Wait for the subprocess that opens the browser window, preventing zombie processes #1488 
 
+* Hooks:
+  - Handle tool_input passed as string gracefully instead of failing (Copilot CLI sends strings).
+
 Dependencies:
   - Add dependency `oslex`
 

src/serena/hooks.py

@@ -70,7 +70,11 @@ class PreToolUseHook(Hook, ABC):
         if not _tool_name:
             raise ValueError("Tool name is required in the hook input data")
         self._tool_name = _tool_name
-        self._tool_input: dict | None = self._input_data.get("tool_input") or self._input_data.get("toolInput")
+        raw_tool_input = self._input_data.get("tool_input") or self._input_data.get("toolInput")
+        # TODO: some agents, like copilot CLI, can send a string as value for raw_tool_input
+        #  Example: "tool_input":"*** Begin Patch\n*** Add File: /Users/acbdef/.copilot/session-state/08a961db-02f0-4c7c-b783-1e9818290292/files/hook-tool-test-3.txt\n+third edit tool test\n*** End Patch\n"
+        #  We currently don't parse such tool input and hence don't react to it in hooks
+        self._tool_input: dict | None = raw_tool_input if isinstance(raw_tool_input, dict) else None
 
         # only relevant in claude code at the moment, (not all events include this field; default to empty string)
         raw_permission_mode = self._input_data.get("permission_mode") or self._input_data.get("permissionMode") or ""