diff --git a/app/services/mcp_client.py b/app/services/mcp_client.py
index d4bb49b..06972ad 100644
--- a/app/services/mcp_client.py
+++ b/app/services/mcp_client.py
@@ -189,7 +189,8 @@ async def _handshake(url: str, headers: dict | None) -> dict:
     return session
 
 
-def _server(connector_id: int) -> dict:
+def _server(connector_id: int, *, workspace_id: int | None = None,
+              distribute=None) -> dict:
     row = get(connector_id)
     if row is None:
         raise ValueError("Serveur MCP introuvable")
@@ -198,7 +199,8 @@ def _server(connector_id: int) -> dict:
     if not row["enabled"]:
         raise ValueError("Serveur MCP désactivé")
     return {"id": row["id"], "name": row["name"], "url": row["url"],
-            "headers": _headers(connector_id)}
+            "headers": _headers(connector_id, workspace_id=workspace_id,
+                                distribute=distribute)}
 
 
 def _normalize(server: dict, raw: list) -> list[dict]:
@@ -226,10 +228,16 @@ def _save_tools(connector_id: int, tools: list[dict]) -> None:
         conn.commit()
 
 
-async def initialize_and_list(connector_id: int) -> list[dict]:
-    """Handshake + ``tools/list`` → met à jour le cache de la base."""
-    srv = _server(connector_id)
-    url = _with_secret(srv["url"], connector_id)
+async def initialize_and_list(connector_id: int, *, workspace_id: int | None = None,
+                              distribute=None) -> list[dict]:
+    """Handshake + ``tools/list`` → met à jour le cache de la base.
+
+    Pour un serveur à référence ObsiGate, ``workspace_id`` est obligatoire
+    (isolation vérifiée avant distribution, voir ``connectors``).
+    """
+    srv = _server(connector_id, workspace_id=workspace_id, distribute=distribute)
+    url = _with_secret(srv["url"], connector_id, workspace_id=workspace_id,
+                       distribute=distribute)
     session = await _handshake(url, srv["headers"])
     data = await _rpc(url, {"jsonrpc": "2.0", "id": 2, "method": "tools/list",
                             "params": {}}, session)
@@ -276,14 +284,16 @@ def _content_text(result: dict) -> str:
     return "\n".join(p for p in parts if p) or json.dumps(result, ensure_ascii=False)[:4000]
 
 
-async def call_tool(connector_id: int, tool: str, arguments: dict | None = None) -> dict:
+async def call_tool(connector_id: int, tool: str, arguments: dict | None = None, *,
+                    workspace_id: int | None = None, distribute=None) -> dict:
     """``tools/call`` → {status, text} (isError → error, borné à 20 000 car.).
 
     Le handshake (avec session éventuelle) précède systématiquement
     l'appel : c'est la condition T0 des serveurs à session.
     """
-    srv = _server(connector_id)
-    url = _with_secret(srv["url"], connector_id)
+    srv = _server(connector_id, workspace_id=workspace_id, distribute=distribute)
+    url = _with_secret(srv["url"], connector_id, workspace_id=workspace_id,
+                       distribute=distribute)
     session = await _handshake(url, srv["headers"])
     data = await _rpc(url, {
         "jsonrpc": "2.0", "id": 3, "method": "tools/call",