diff --git a/workers.aqua b/workers.aqua
index 8c379b6..610fcc1 100644
--- a/workers.aqua
+++ b/workers.aqua
@@ -17,3 +17,17 @@ service Worker("worker"):
 
     -- Returns list of all workers.
     list() -> []PeerId
+
+    -- Restarts worker installation spell.
+    -- Can be called only by system spells or peer manager,
+    -- Throws an error if worker doesn't exist.
+    activate(deal_id: string)
+
+    -- Stops all worker spells and drops all incoming particles until activation.
+    -- Can be called only by system spells or peer manager,
+    -- Throws an error if worker doesn't exist.
+    deactivate(deal_id: string)
+
+    -- Returns true if worker is active.
+    -- Throws an error if worker doesn't exist.
+    is_active(deal_id: string) -> bool