diff --git a/surfsense_mcp/tests/test_get_document_okf.py b/surfsense_mcp/tests/test_get_document_okf.py
new file mode 100644
index 000000000..8b5cdae2f
--- /dev/null
+++ b/surfsense_mcp/tests/test_get_document_okf.py
@@ -0,0 +1,68 @@
+"""surfsense_get_document round-trips through the real tool registration.
+
+The markdown form must ask the backend for the OKF concept via content
+negotiation (``Accept: text/markdown``) and pass it through untouched; the JSON
+form must leave the default ``application/json`` Accept in place. This is the
+only coverage of the MCP-side glue that forwards the header.
+"""
+
+from __future__ import annotations
+
+import asyncio
+from unittest.mock import MagicMock
+
+import httpx
+from mcp.server.fastmcp import FastMCP
+
+from mcp_server.core.client import SurfSenseClient
+from mcp_server.features.knowledge_base import search_tools
+
+_CONCEPT = "---\ntype: Note\ntitle: T\n---\n\nBody."
+
+
+def _client_recording(seen: dict) -> SurfSenseClient:
+    async def handler(request: httpx.Request) -> httpx.Response:
+        seen["path"] = request.url.path
+        seen["accept"] = request.headers.get("accept")
+        if "text/markdown" in (seen["accept"] or ""):
+            return httpx.Response(
+                200, text=_CONCEPT, headers={"content-type": "text/markdown"}
+            )
+        return httpx.Response(200, json={"id": 1, "title": "T"})
+
+    client = SurfSenseClient(
+        api_base="http://test/api/v1", timeout=5, fallback_api_key="ss_pat_x"
+    )
+    client._http = httpx.AsyncClient(
+        base_url="http://test/api/v1",
+        headers={"Accept": "application/json"},
+        transport=httpx.MockTransport(handler),
+    )
+    return client
+
+
+def _call_get_document(client: SurfSenseClient, **arguments) -> str:
+    mcp = FastMCP("test")
+    search_tools.register(mcp, client, MagicMock())
+    blocks = asyncio.run(mcp.call_tool("surfsense_get_document", arguments))
+    return "".join(block.text for block in blocks)
+
+
+def test_markdown_requests_okf_concept_and_passes_it_through():
+    seen: dict = {}
+    text = _call_get_document(_client_recording(seen), document_id=1)
+
+    assert seen["path"] == "/api/v1/documents/1"
+    assert "text/markdown" in seen["accept"]
+    assert text == _CONCEPT
+
+
+def test_json_keeps_default_accept():
+    seen: dict = {}
+    text = _call_get_document(
+        _client_recording(seen), document_id=1, response_format="json"
+    )
+
+    assert seen["path"] == "/api/v1/documents/1"
+    assert seen["accept"] == "application/json"
+    assert '"id": 1' in text