fix(tools): harden composite-description handling after review

- Anchor the pre-baked-composite check to the actual three-line block
  shape instead of a naive substring match, so authored prose that
  merely mentions "Tool Description:" is never truncated (CodeRabbit /
  Bugbot review finding). Shared as
  strip_composite_description_prefix() and reused by the function-
  calling schema builder, which had the same naive split.
- Make render_text_description_and_args tolerate duck-typed tools
  without a real formatted_description string (fixes CI: step-executor
  tests pass Mock tools whose auto-created attribute is not a str).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/crewai/src/crewai/tools/structured_tool.py

@@ -4,6 +4,7 @@ import asyncio
 from collections.abc import Callable
 import inspect
 import json
+import re
 import textwrap
 from typing import TYPE_CHECKING, Annotated, Any, cast, get_type_hints
 import warnings
@@ -111,6 +112,30 @@ def build_schema_hint(args_schema: type[BaseModel]) -> str:
         return ""
 
 
+# Matches a description that IS a pre-composed LLM block (as written by
+# older versions into the field, and by adapters that still bake it in).
+# Anchored to the full three-line shape so authored prose that merely
+# mentions "Tool Description:" is never mistaken for a composite. Greedy
+# ``.*`` keeps only the text after the LAST marker, matching the historical
+# split behavior for nested pre-baked blocks.
+_COMPOSITE_DESCRIPTION_RE = re.compile(
+    r"^Tool Name:.*\nTool Arguments:.*\nTool Description:\s*",
+    re.DOTALL,
+)
+
+
+def strip_composite_description_prefix(description: str) -> str:
+    """Return the authored text from a pre-composed LLM description block.
+
+    Descriptions that don't start with the composite shape are returned
+    unchanged.
+    """
+    match = _COMPOSITE_DESCRIPTION_RE.match(description)
+    if match:
+        return description[match.end() :]
+    return description
+
+
 def format_description_for_llm(
     name: str,
     args_schema: type[BaseModel] | None,
@@ -123,10 +148,12 @@ def format_description_for_llm(
     ``description`` field itself is never mutated — prompt rendering calls
     this on demand.
 
-    Idempotent: if ``description`` already contains a composed block (e.g.
-    a tool deserialized from a checkpoint written by an older version, or
-    an adapter that bakes the composite into the field), only the authored
-    text after the last ``"Tool Description:"`` marker is used.
+    Idempotent: if ``description`` already *is* a composed block (e.g. a
+    tool deserialized from a checkpoint written by an older version, or an
+    adapter that bakes the composite into the field), only the authored
+    text after the marker is used. The check is anchored to the composite
+    shape, so authored prose that merely mentions ``"Tool Description:"``
+    passes through untouched.
 
     Args:
         name: The tool name (sanitized for the prompt).
@@ -136,8 +163,7 @@ def format_description_for_llm(
     Returns:
         The composed, LLM-facing description block.
     """
-    if "Tool Description:" in description:
-        description = description.split("Tool Description:")[-1].strip()
+    description = strip_composite_description_prefix(description)
     if args_schema is not None:
         schema = generate_model_description(args_schema)
         args_json = json.dumps(schema["json_schema"]["schema"], indent=2)

lib/crewai/src/crewai/utilities/agent_utils.py

@@ -27,7 +27,10 @@ from crewai.agents.parser import (
 from crewai.llms.base_llm import BaseLLM, call_stop_override
 from crewai.tools import BaseTool as CrewAITool
 from crewai.tools.base_tool import BaseTool
-from crewai.tools.structured_tool import CrewStructuredTool
+from crewai.tools.structured_tool import (
+    CrewStructuredTool,
+    strip_composite_description_prefix,
+)
 from crewai.tools.tool_types import ToolResult
 from crewai.utilities.errors import AgentRepositoryError
 from crewai.utilities.exceptions.context_window_exceeding_exception import (
@@ -147,7 +150,14 @@ def render_text_description_and_args(
     Returns:
         Plain text description of tools.
     """
-    tool_strings = [tool.formatted_description for tool in tools]
+    # Fall back to the raw description for duck-typed tools (including test
+    # mocks) that don't provide a real formatted_description string.
+    tool_strings = [
+        formatted
+        if isinstance((formatted := getattr(tool, "formatted_description", None)), str)
+        else tool.description
+        for tool in tools
+    ]
     return "\n".join(tool_strings)
 
 
@@ -190,10 +200,10 @@ def convert_tools_to_openai_schema(
             except Exception:
                 parameters = {}
 
-        # BaseTool formats description as "Tool Name: ...\nTool Arguments: ...\nTool Description: {original}"
-        description = tool.description
-        if "Tool Description:" in description:
-            description = description.split("Tool Description:")[-1].strip()
+        # Old checkpoints and some adapters bake the composed LLM block
+        # ("Tool Name: ...\nTool Arguments: ...\nTool Description: {authored}")
+        # into the description field; keep only the authored text here.
+        description = strip_composite_description_prefix(tool.description)
 
         sanitized_name = sanitize_tool_name(tool.name)
 

lib/crewai/tests/tools/test_base_tool.py

@@ -752,6 +752,20 @@ class TestAuthoredDescriptionPreserved:
             "Tool Description: Edited description."
         )
 
+    def test_prose_mentioning_the_marker_is_not_truncated(self):
+        """Authored text that merely mentions "Tool Description:" must reach
+        the LLM untouched — only descriptions that ARE a pre-composed block
+        (anchored three-line shape) get stripped."""
+        tool_instance = self._make_tool()
+        prose = (
+            "Formats prompts. The output includes a line reading "
+            "'Tool Description:' followed by the tool's summary."
+        )
+        tool_instance.description = prose
+        assert tool_instance.formatted_description.endswith(
+            f"Tool Description: {prose}"
+        )
+
     def test_composite_is_not_reapplied_to_prebaked_descriptions(self):
         """A description that already contains a composed block (old
         checkpoints, adapters that bake the composite into the field) must