diff --git a/sandbox/pyproject.toml b/sandbox/pyproject.toml
index 029ae86..2d0a5e7 100644
--- a/sandbox/pyproject.toml
+++ b/sandbox/pyproject.toml
@@ -22,9 +22,9 @@ dependencies = [
 [project.scripts]
 mcp-server-plaid = "mcp_server_plaid:main"
 
-[tool.pytest]
+[tool.pytest.ini_options]
 testpaths = ["src/mcp_server_plaid/test"]
-python_files = "test_*.py"
+python_files = ["test_*.py"]
 
 [project.optional-dependencies]
 test = [
diff --git a/sandbox/src/mcp_server_plaid/tools/tool_search_documentation.py b/sandbox/src/mcp_server_plaid/tools/tool_search_documentation.py
index 4d1e526..47156de 100644
--- a/sandbox/src/mcp_server_plaid/tools/tool_search_documentation.py
+++ b/sandbox/src/mcp_server_plaid/tools/tool_search_documentation.py
@@ -33,12 +33,42 @@
 )
 
 
+def _escape_md_brackets(text: str) -> str:
+    """Escape characters that would break a markdown link's title text."""
+    return text.replace("\\", "\\\\").replace("[", "\\[").replace("]", "\\]")
+
+
+def _format_sources(sources: List[Dict[str, Any]]) -> str:
+    """Format AskBill source metadata as a deduplicated markdown bullet list."""
+    seen_urls = set()
+    lines = []
+    for source in sources:
+        url = source.get("url", "")
+        title = source.get("title", "") or url
+        if url and url in seen_urls:
+            continue
+        if url:
+            seen_urls.add(url)
+            if title != url:
+                lines.append(f"- [{_escape_md_brackets(title)}](<{url}>)")
+            else:
+                lines.append(f"- <{url}>")
+        elif title:
+            lines.append(f"- {_escape_md_brackets(title)}")
+    return "\n".join(lines)
+
+
 # Tool handler
 async def handle_search_documentation(
         arguments: Dict[str, Any], *, bill_client: AskBillClient, **_
 ) -> List[types.TextContent | types.ImageContent | types.EmbeddedResource]:
     response = await bill_client.ask_question(question=arguments["question"])
-    return [types.TextContent(type="text", text=str(response["answer"]))]
+    answer = str(response["answer"])
+    sources = response.get("sources") or []
+    formatted_sources = _format_sources(sources)
+    if formatted_sources:
+        answer = f"{answer.rstrip()}\n\n## Sources\n{formatted_sources}"
+    return [types.TextContent(type="text", text=answer)]
 
 
 registry.register(SEARCH_DOCUMENTATION_TOOL, handle_search_documentation)