diff --git a/lib_cache/current_cache.ml b/lib_cache/current_cache.ml
index 2b43a6a4..e327d134 100644
--- a/lib_cache/current_cache.ml
+++ b/lib_cache/current_cache.ml
@@ -583,6 +583,9 @@ module S = S
 module Db = struct
   include Db
 
+  let key ~job_id = 
+    lookup_job_id job_id |> Option.map snd
+
   let history ~limit ~job_id =
     let key =
       match Hashtbl.find_opt key_of_job_id job_id with
diff --git a/lib_cache/current_cache.mli b/lib_cache/current_cache.mli
index 5ac1b8bc..6e29264e 100644
--- a/lib_cache/current_cache.mli
+++ b/lib_cache/current_cache.mli
@@ -77,4 +77,7 @@ module Db : sig
   val history : limit:int -> job_id:string -> string option * entry list
   (** [history ~limit ~job_id] returns the in-progress build (if any),
       and the [limit] most recent builds with the same key as [job_id]. *)
+
+  val key : job_id:string -> string option
+  (** [key ~job_id] returns the serialised key associated with the job [job_id] if any. *)
 end