diff --git a/pageindex/backend/local.py b/pageindex/backend/local.py
index ec68943..ab377f7 100644
--- a/pageindex/backend/local.py
+++ b/pageindex/backend/local.py
@@ -306,6 +306,14 @@ class LocalBackend:
                 result = backend.get_page_content(col_name, doc_id, pages)
             except DocumentNotFoundError:
                 return json.dumps({"error": f"doc_id '{doc_id}' not found."})
+            except (ValueError, AttributeError) as e:
+                # A malformed page spec ("all", "5-") is a recoverable bad tool
+                # argument: hand the model an actionable error it can correct
+                # (mirroring the legacy retrieval tool) rather than letting the
+                # ValueError surface as the agent SDK's generic tool-failure text.
+                return json.dumps({
+                    "error": f"Invalid pages format: {pages!r}. Use '5-7', '3,8', or '12'. Error: {e}"
+                })
             return json.dumps(result, ensure_ascii=False)
 
         tools = [get_document, get_document_structure, get_page_content]
diff --git a/tests/test_local_backend.py b/tests/test_local_backend.py
index ccc0f23..1bb9662 100644
--- a/tests/test_local_backend.py
+++ b/tests/test_local_backend.py
@@ -127,6 +127,18 @@ def test_scoped_mode_allows_in_scope_doc_id(populated_backend):
     assert out.get("doc_name") == "alpha.pdf"
 
 
+@pytest.mark.parametrize("bad_pages", ["all", "5-", "abc", "3-1"])
+def test_get_page_content_returns_actionable_error_for_bad_page_spec(populated_backend, bad_pages):
+    # A malformed page spec must come back as a correctable JSON error (like the
+    # legacy retrieval tool), not the agent SDK's generic tool-failure fallback,
+    # so the model can retry with a valid range instead of giving up.
+    tools = populated_backend.get_agent_tools("papers", doc_ids=["d1"])
+    by_name = {t.name: t for t in tools.function_tools}
+    out = json.loads(_invoke_tool(by_name["get_page_content"], {"doc_id": "d1", "pages": bad_pages}))
+    assert "error" in out
+    assert "Invalid pages format" in out["error"]
+
+
 def test_wrap_with_doc_context_single(populated_backend):
     from pageindex.agent import wrap_with_doc_context
     docs = populated_backend._scoped_docs("papers", ["d1"])