diff --git a/src/main/scala/uncore/tilelink2/Nodes.scala b/src/main/scala/uncore/tilelink2/Nodes.scala
index a0de1a84..c9482e69 100644
--- a/src/main/scala/uncore/tilelink2/Nodes.scala
+++ b/src/main/scala/uncore/tilelink2/Nodes.scala
@@ -17,6 +17,9 @@ abstract class NodeImp[PO, PI, EO, EI, B <: Data]
   def bundleO(eo: Seq[EO]): Vec[B]
   def bundleI(ei: Seq[EI]): Vec[B]
   def connect(bo: B, eo: EO, bi: B, ei: EI)(implicit sourceInfo: SourceInfo): Unit
+  // If you want to track parameters as they flow through nodes, overload these:
+  def mixO(po: PO, node: BaseNode[PO, PI, EO, EI, B]): PO = po
+  def mixI(pi: PI, node: BaseNode[PO, PI, EO, EI, B]): PI = pi
 }
 
 class RootNode
@@ -59,12 +62,12 @@ class BaseNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])(
   private lazy val oParams : Seq[PO] = {
     val o = oFn(oPorts.size, iPorts.map{ case (i, n) => n.oParams(i) })
     reqE(oPorts.size, o.size)
-    o
+    o.map(imp.mixO(_, this))
   }
   private lazy val iParams : Seq[PI] = {
     val i = iFn(iPorts.size, oPorts.map{ case (o, n) => n.iParams(o) })
     reqE(i.size, iPorts.size)
-    i
+    i.map(imp.mixI(_, this))
   }
 
   lazy val edgesOut = (oPorts zip oParams).map { case ((i, n), o) => imp.edgeO(o, n.iParams(i)) }