diff --git a/src/backend/bisheng_langchain/gpts/tools/code_interpreter/local_executor.py b/src/backend/bisheng_langchain/gpts/tools/code_interpreter/local_executor.py
index 69fc65de5..fe711f9a4 100644
--- a/src/backend/bisheng_langchain/gpts/tools/code_interpreter/local_executor.py
+++ b/src/backend/bisheng_langchain/gpts/tools/code_interpreter/local_executor.py
@@ -36,7 +36,14 @@ are subfolders of the current working directory. NEVER use an absolute path with
 leading slash such as `/output/...` or `/scratch/...` — anything written outside the \
 current working directory is DISCARDED and will NOT be delivered to the user. \
 Do not use things like plot.show() as it will not work; save figures to `output/` \
-instead. print() any output and results so you can capture the output."""
+instead. print() any output and results so you can capture the output. \
+AVAILABLE LIBRARIES: this runs in the backend Python environment; these are ALREADY \
+installed — pandas, numpy, matplotlib (charts), openpyxl / XlsxWriter (Excel), \
+python-docx (Word), Pillow (images), reportlab (generate PDF), and PyMuPDF a.k.a. \
+`fitz` (read/parse PDF). To READ text or tables from a PDF, use `import fitz` \
+(PyMuPDF); do NOT use pdfminer / pdfplumber / PyPDF2 — they are NOT installed. If an \
+import fails, switch to an already-installed library instead of assuming a package \
+exists; do NOT run `pip install` (this is a shared, offline environment)."""
 
 
 class LocalExecutor(BaseExecutor):
diff --git a/src/backend/test/linsight/test_code_interpreter_output_path.py b/src/backend/test/linsight/test_code_interpreter_output_path.py
index 36fa33604..95b743875 100644
--- a/src/backend/test/linsight/test_code_interpreter_output_path.py
+++ b/src/backend/test/linsight/test_code_interpreter_output_path.py
@@ -113,3 +113,23 @@ def test_run_failure_path_returns_without_notice(monkeypatch):
     assert "log" in result
     # failure path returns early — no file_list, no notice appended
     assert "file_list" not in result
+
+
+# ---------------------------------------------------------------------------
+# LOCAL_DESCRIPTION: available-library guidance
+# ---------------------------------------------------------------------------
+def test_description_guides_to_installed_pdf_and_data_libs():
+    """The tool description names installed libraries and steers PDF reads to
+    `fitz`, away from pdfminer/pdfplumber/PyPDF2 which the model tends to reach
+    for but are NOT installed in the backend env. Prevents regressing the
+    guidance that stops spurious 'No module named pdfminer' output.
+    """
+    d = LocalExecutor(minio={}).description
+    # PDF read guidance points at the installed lib, not the model's defaults
+    assert "fitz" in d
+    assert "pdfminer" in d and "NOT installed" in d
+    # names an installed PDF generator + core data lib so the model won't guess
+    assert "reportlab" in d
+    assert "pandas" in d
+    # shared, offline env — must not encourage pip install
+    assert "pip install" in d