diff --git a/src/agentic_cli/mcp/context7.py b/src/agentic_cli/mcp/context7.py
index 4de4240..9c5ff1a 100644
--- a/src/agentic_cli/mcp/context7.py
+++ b/src/agentic_cli/mcp/context7.py
@@ -100,10 +100,14 @@ def to_markdown(self) -> str:
                 if document.summary:
                     detail_lines.append(f"Summary: {document.summary.strip()}")
                 elif document.content:
-                    preview = document.content.strip().splitlines()[0]
-                    if len(preview) > 160:
-                        preview = preview[:157] + "..."
-                    detail_lines.append(f"Preview: {preview}")
+                    stripped_content = document.content.strip()
+                    if stripped_content:
+                        preview_lines = stripped_content.splitlines()
+                        if preview_lines:
+                            preview = preview_lines[0]
+                            if len(preview) > 160:
+                                preview = preview[:157] + "..."
+                            detail_lines.append(f"Preview: {preview}")
                 if document.source:
                     detail_lines.append(f"Source: {document.source}")
                 if document.metadata:
diff --git a/tests/test_mcp_context7.py b/tests/test_mcp_context7.py
index ed0d39d..d9ace34 100644
--- a/tests/test_mcp_context7.py
+++ b/tests/test_mcp_context7.py
@@ -132,6 +132,22 @@ def fake_timestamped_dir(prefix: str) -> Path:
     assert dummy_client.closed is False
 
 
+def test_docs_markdown_omits_preview_for_whitespace_content() -> None:
+    """Whitespace-only content does not produce a preview entry."""
+
+    response = Context7DocsResponse(
+        package="example@1.0.0",
+        library=Context7Library(id="example", name="Example"),
+        documents=[
+            Context7Document(title="Doc", content="   \n\n   "),
+        ],
+    )
+
+    markdown = response.to_markdown()
+
+    assert "Preview:" not in markdown
+
+
 def test_run_docs_requires_configuration(capsys) -> None:
     """If Context7 is not configured the command exits early."""