docs(tools): state what the declared-path pin means across a rebuild

Bugbot flagged that `model_post_init` re-derives `_declared_realpath` from
the serialized `file_path`, so a rebuild in a different working directory can
repoint the declared default. The mechanism is real. Traced it to exactly one
case of three:

  absolute file_path              -> survives a rebuild anywhere
  relative file_path + base_dir   -> survives; base_dir is anchored already
  relative file_path, no base_dir -> re-anchors to the rebuilding cwd

Keeping the re-anchor, deliberately. A bare relative path names nothing
absolute to preserve, and the alternative is pinning a directory that, for a
rebuild in a fresh container, no longer exists — reading a stale absolute path
would be the worse failure. It is also not a regression in any case: before
this branch a rebuilt reader lost the declared file outright and answered "No
file path provided".

Rewriting `file_path` to its resolved form at construction would close it,
but `tests/agents/test_agent.py:2311` pins that the authored string survives,
so that is a public-contract change rather than a fix. A serialized pin field
would too, at the cost of a schema change — noted on the thread for whoever
reviews, not taken unilaterally.

So: all three cases now have a test, and the class docstring says which is
which, so the behavior is a decision rather than something a reader has to
infer. 38 tests in the seam suite, 338 across the file tools and crewai's
tool suite.

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

Author: joaomdmoura

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

@@ -50,6 +50,15 @@ class FileReadTool(BaseTool):
     construction, so a later chdir cannot repoint it, and it can be addressed
     either by omitting ``file_path`` or by the label shown in the description.
 
+    That pin is anchored from what was declared, which matters when a tool is
+    rebuilt from a serialized crew in a different working directory. An
+    absolute ``file_path``, or a relative one with ``base_dir`` set, names the
+    same file after the rebuild as before it. A *relative* ``file_path`` with
+    no ``base_dir`` names nothing absolute, so it re-anchors to the working
+    directory of the process doing the rebuilding — the same file the same
+    arguments would have named there. Pass ``base_dir`` when a declared
+    relative path must survive a move.
+
     Args:
         file_path (Optional[str]): Path to the file to be read. If provided,
             this becomes the default file path for the tool.

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

@@ -404,6 +404,70 @@ def test_reader_round_trips_through_model_dump(store, tmp_path, monkeypatch):
     assert rebuilt._run() == "dumped\n"
 
 
+# --- what the declared-path pin means across a rebuild -----------------------
+#
+# The pin is derived from what was *declared*, so whether it survives a rebuild
+# in a different working directory depends on whether the declaration named
+# somewhere absolute. These three cases are the whole story; they are pinned
+# here so the behavior is a decision rather than an accident. Note the local
+# store is the one that makes this observable, since its `normalize` is the one
+# that consults the process cwd.
+
+
+def test_an_absolute_declared_path_survives_a_rebuild_elsewhere(tmp_path, monkeypatch):
+    """The strongest case: an absolute declaration is cwd-independent."""
+    here, there = tmp_path / "here", tmp_path / "there"
+    here.mkdir(), there.mkdir()
+    (here / "notes.txt").write_text("from here\n")
+    (there / "notes.txt").write_text("from there\n")
+
+    monkeypatch.chdir(here)
+    dumped = FileReadTool(file_path=str(here / "notes.txt")).model_dump()
+    monkeypatch.chdir(there)
+    rebuilt = FileReadTool.model_validate(dumped)
+
+    assert rebuilt._run() == "from here\n"
+
+
+def test_a_declared_base_dir_pins_a_relative_path_across_a_rebuild(tmp_path, monkeypatch):
+    """base_dir is anchored at construction, so it carries the pin with it."""
+    here, there = tmp_path / "here", tmp_path / "there"
+    here.mkdir(), there.mkdir()
+    (here / "notes.txt").write_text("from here\n")
+    (there / "notes.txt").write_text("from there\n")
+
+    monkeypatch.chdir(here)
+    dumped = FileReadTool(file_path="notes.txt", base_dir=str(here)).model_dump()
+    monkeypatch.chdir(there)
+    rebuilt = FileReadTool.model_validate(dumped)
+
+    assert rebuilt._run() == "from here\n"
+
+
+def test_a_bare_relative_declared_path_reanchors_on_rebuild(tmp_path, monkeypatch):
+    """A relative path with no base_dir names nothing absolute to preserve.
+
+    It re-anchors to the rebuilding process's working directory — the same file
+    the same arguments would name there. Documented rather than "fixed": the
+    alternative is pinning a path from a working directory that, for a rebuild
+    in a fresh container, no longer exists. Callers needing the pin to survive
+    pass `base_dir`, which the test above covers.
+    """
+    here, there = tmp_path / "here", tmp_path / "there"
+    here.mkdir(), there.mkdir()
+    (here / "notes.txt").write_text("from here\n")
+    (there / "notes.txt").write_text("from there\n")
+
+    monkeypatch.chdir(here)
+    dumped = FileReadTool(file_path="notes.txt").model_dump()
+    monkeypatch.chdir(there)
+    rebuilt = FileReadTool.model_validate(dumped)
+
+    assert rebuilt._run() == "from there\n"
+    # And it is a real re-anchor, not a stale absolute path that happens to read.
+    assert rebuilt._declared_realpath == str(there / "notes.txt")
+
+
 # --- a store that fails ------------------------------------------------------
 #
 # A store may fail where the local filesystem never could. Every exit from