diff --git a/runtime/src/main/java/org/capnproto/CallContext.java b/runtime/src/main/java/org/capnproto/CallContext.java
index a01d9e6..49279f0 100644
--- a/runtime/src/main/java/org/capnproto/CallContext.java
+++ b/runtime/src/main/java/org/capnproto/CallContext.java
@@ -8,7 +8,7 @@ public class CallContext<Params, Results> {
     private final FromPointerReader<Params> params;
     private final FromPointerBuilder<Results> results;
 
-    CallContext(FromPointerReader<Params> params,
+    public CallContext(FromPointerReader<Params> params,
                 FromPointerBuilder<Results> results,
                 CallContextHook hook) {
         this.hook = hook;