diff --git a/CHANGELOG.md b/CHANGELOG.md
index 33f28a8..61b9057 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,11 @@
 
 All notable changes to `uipath_llm_client` (core package) will be documented in this file.
 
+## [1.18.5] - 2026-09-07
+
+### Fixed
+- `UiPathAPIError.__str__` no longer includes the response body. The `traceback` module renders the final exception line with `str()`, so a relayed provider error body was copied verbatim into every printed stacktrace — including the one shipped as `AgentRun.Failed.ErrorTraceback` — regardless of what the consuming runtime chose to put in its own customer-facing error. The body is content of unknown sensitivity and may carry PII, so it now stays on the `body` attribute (unchanged, for callers that classify on it) and out of the serialized form. `__repr__` is unchanged. (PC-5002)
+
 ## [1.18.0] - 2026-08-13
 
 ### Changed
diff --git a/packages/uipath_langchain_client/CHANGELOG.md b/packages/uipath_langchain_client/CHANGELOG.md
index 526b958..0bbe841 100644
--- a/packages/uipath_langchain_client/CHANGELOG.md
+++ b/packages/uipath_langchain_client/CHANGELOG.md
@@ -2,6 +2,11 @@
 
 All notable changes to `uipath_langchain_client` will be documented in this file.
 
+## [1.18.5] - 2026-09-07
+
+### Changed
+- Bumped the `uipath-llm-client` floor to `>=1.18.5`, which stops `UiPathAPIError.__str__` from copying the response body into printed stacktraces. (PC-5002)
+
 ## [1.18.4] - 2026-09-02
 
 ### Fixed
diff --git a/packages/uipath_langchain_client/pyproject.toml b/packages/uipath_langchain_client/pyproject.toml
index 295b6ba..4dbdd9f 100644
--- a/packages/uipath_langchain_client/pyproject.toml
+++ b/packages/uipath_langchain_client/pyproject.toml
@@ -6,7 +6,7 @@ readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
     "langchain>=1.2.15,<2.0.0",
-    "uipath-llm-client>=1.18.0,<2.0.0",
+    "uipath-llm-client>=1.18.5,<2.0.0",
 ]
 
 [project.optional-dependencies]
diff --git a/packages/uipath_langchain_client/src/uipath_langchain_client/__version__.py b/packages/uipath_langchain_client/src/uipath_langchain_client/__version__.py
index b91c30e..c149855 100644
--- a/packages/uipath_langchain_client/src/uipath_langchain_client/__version__.py
+++ b/packages/uipath_langchain_client/src/uipath_langchain_client/__version__.py
@@ -1,3 +1,3 @@
 __title__ = "UiPath LangChain Client"
 __description__ = "A Python client for interacting with UiPath's LLM services via LangChain."
-__version__ = "1.18.4"
+__version__ = "1.18.5"
diff --git a/src/uipath/llm_client/__version__.py b/src/uipath/llm_client/__version__.py
index d908879..8dacbda 100644
--- a/src/uipath/llm_client/__version__.py
+++ b/src/uipath/llm_client/__version__.py
@@ -1,3 +1,3 @@
 __title__ = "UiPath LLM Client"
 __description__ = "A Python client for interacting with UiPath's LLM services."
-__version__ = "1.18.0"
+__version__ = "1.18.5"
diff --git a/src/uipath/llm_client/utils/exceptions.py b/src/uipath/llm_client/utils/exceptions.py
index 2648321..e717db2 100644
--- a/src/uipath/llm_client/utils/exceptions.py
+++ b/src/uipath/llm_client/utils/exceptions.py
@@ -205,10 +205,10 @@ def _parse_retry_after(response: Response) -> float | None:
         return None
 
     def __str__(self) -> str:
-        return (
-            f"{self.__class__.__name__}: {self.message} "
-            f"(Status Code: {self.status_code}) {self.body}"
-        )
+        # ``self.body`` is deliberately absent. The traceback module renders the
+        # final exception line with str(), so anything here is copied verbatim
+        # into every printed stacktrace -- potentially including PII
+        return f"{self.__class__.__name__}: {self.message} (Status Code: {self.status_code})"
 
     def __repr__(self) -> str:
         return (
diff --git a/tests/core/features/test_exceptions.py b/tests/core/features/test_exceptions.py
index 823f504..6f73423 100644
--- a/tests/core/features/test_exceptions.py
+++ b/tests/core/features/test_exceptions.py
@@ -124,6 +124,34 @@ def test_str_format(self):
         assert "Bad Request" in s
         assert "400" in s
 
+    @pytest.mark.parametrize(
+        "body_json,body_text",
+        [
+            ({"error": {"message": "PROVIDER_SECRET_MSG"}}, None),
+            (None, "PROVIDER_SECRET_MSG"),
+        ],
+        ids=["json-body", "text-body"],
+    )
+    def test_str_omits_the_response_body(self, body_json, body_text):
+        """The body may relay provider content of unknown sensitivity (PC-5002).
+
+        str() is what the traceback module prints as the final exception line, so
+        anything here reaches every serialized stacktrace.
+        """
+        resp = self._make_response(400, "Bad Request", body_json=body_json, body_text=body_text)
+        exc = UiPathAPIError.from_response(resp)
+
+        assert "PROVIDER_SECRET_MSG" not in str(exc)
+        assert str(exc) == "UiPathBadRequestError: Bad Request (Status Code: 400)"
+
+    def test_str_omission_does_not_drop_the_body_attribute(self):
+        """Callers classify on .body -- it must survive the __str__ redaction."""
+        body = {"error": {"message": "PROVIDER_SECRET_MSG", "param": "max_tokens"}}
+        resp = self._make_response(400, "Bad Request", body_json=body)
+        exc = UiPathAPIError.from_response(resp)
+
+        assert exc.body == body
+
     def test_repr_format(self):
         resp = self._make_response(404, "Not Found", body_json={"error": "missing"})
         exc = UiPathAPIError.from_response(resp)