fix(tools): reset the description when the declared-file pin is lost

Bugbot caught a hole in the previous commit's own fix. Guarding the declared
-file derivation clears `_declared_realpath` and `_declared_label`, but
`description` is a serialized *field* — on a `model_validate` rebuild it
arrives already saying "The default file is notes.txt, which is read when
'file_path' is omitted".

So a rebuilt reader that lost its pin still advertised a default it could not
read. The LLM would take the tool at its word, call it with no arguments, and
get "No file path provided" — the tool lying about its own contract, which is
worse than the missing default it was meant to degrade to.

The failure path now restores the class-default description alongside clearing
the pin, so what the tool says and what it does stay matched.

105 tests across the file tools; the new one asserts a real dumped description
advertises the default, and that after a rebuild losing the pin it does not,
matches the class default, and reports "No file path provided" on a bare call.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UNumDnNbiyw3pv1WakAe6t

lib/crewai-tools/src/crewai_tools/tools/file_read_tool/file_read_tool.py

@@ -173,6 +173,16 @@ class FileReadTool(BaseTool):
                 )
                 self._declared_realpath = None
                 self._declared_label = None
+                # The description has to come back too. On a rebuild it arrives
+                # from the serialized data already advertising a default file,
+                # so leaving it would promise the LLM something omitting
+                # 'file_path' can no longer deliver — it would call the tool
+                # with no arguments and get "No file path provided". Restoring
+                # the class default keeps what the tool says matched to what it
+                # does.
+                default = type(self).model_fields["description"].default
+                if isinstance(default, str):
+                    self.description = default
             else:
                 self.description = f"A tool that reads file content. The default file is {self._declared_label}, which is read when 'file_path' is omitted. You can also provide a different 'file_path' parameter to read another file, though reads are confined to the tool's allowed directory and a path that resolves outside it is rejected. Specify 'start_line' and 'line_count' to read specific parts of the file."
 

lib/crewai-tools/tests/file_storage/test_file_store_seam.py

@@ -434,6 +434,29 @@ def test_a_store_failing_on_the_declared_file_still_builds_the_tool(
     assert "No file path provided" in tool._run()
 
 
+def test_a_rebuild_that_loses_the_pin_stops_advertising_a_default(
+    store, failing_store, tmp_path, monkeypatch
+):
+    """What the tool says must match what it does.
+
+    The description is serialized, so on a rebuild it arrives already naming a
+    default file. If the pin is then lost, leaving that text would tell the LLM
+    it can omit `file_path` — and it would get "No file path provided" back.
+    """
+    monkeypatch.chdir(tmp_path)
+    dumped = FileReadTool(file_path="notes.txt").model_dump()
+    assert "The default file is" in dumped["description"]
+
+    # Same tool, rebuilt against a store that can no longer label the path.
+    failing_store("display")
+    rebuilt = FileReadTool.model_validate(dumped)
+
+    assert rebuilt._declared_label is None
+    assert "The default file is" not in rebuilt.description
+    assert rebuilt.description == FileReadTool.model_fields["description"].default
+    assert "No file path provided" in rebuilt._run()
+
+
 def test_a_store_failing_on_base_dir_is_not_swallowed(
     failing_store, tmp_path, monkeypatch
 ):