diff --git a/hydroflow/src/builder/build/pull_filter.rs b/hydroflow/src/builder/build/pull_filter.rs
index bc2336d3590d..25c46e4ca325 100644
--- a/hydroflow/src/builder/build/pull_filter.rs
+++ b/hydroflow/src/builder/build/pull_filter.rs
@@ -23,7 +23,7 @@ where
 type PullBuildImpl<'slf, 'ctx, Prev, Func>
 where
     Prev: PullBuild,
-    Func: 'slf,
+    Func: 'slf + FnMut(&Context, &Prev::ItemOut) -> bool,
 = std::iter::Filter<Prev::Build<'slf, 'ctx>, impl FnMut(&Prev::ItemOut) -> bool>;
 
 impl<Prev, Func> PullBuild for FilterPullBuild<Prev, Func>
diff --git a/hydroflow/src/builder/build/pull_filter_map.rs b/hydroflow/src/builder/build/pull_filter_map.rs
index 44d6d9778f87..d55b04f9f2b0 100644
--- a/hydroflow/src/builder/build/pull_filter_map.rs
+++ b/hydroflow/src/builder/build/pull_filter_map.rs
@@ -23,7 +23,7 @@ where
 type PullBuildImpl<'slf, 'ctx, Prev, Func, Out>
 where
     Prev: PullBuild,
-    Func: 'slf,
+    Func: 'slf + FnMut(&Context, Prev::ItemOut) -> Option<Out>,
 = std::iter::FilterMap<Prev::Build<'slf, 'ctx>, impl FnMut(Prev::ItemOut) -> Option<Out>>;
 
 impl<Prev, Func, Out> PullBuild for FilterMapPullBuild<Prev, Func>
diff --git a/hydroflow/src/builder/build/pull_fold_epoch.rs b/hydroflow/src/builder/build/pull_fold_epoch.rs
index 0c0af0506237..74deea18e4fd 100644
--- a/hydroflow/src/builder/build/pull_fold_epoch.rs
+++ b/hydroflow/src/builder/build/pull_fold_epoch.rs
@@ -25,8 +25,8 @@ where
 type PullBuildImpl<'slf, 'ctx, Prev, Init, Func, Out>
 where
     Prev: 'slf + PullBuild,
-    Init: 'slf,
-    Func: 'slf,
+    Init: 'slf + FnMut(&Context) -> Out,
+    Func: 'slf + FnMut(&Context, Out, Prev::ItemOut) -> Out,
 = std::iter::OnceWith<impl FnOnce() -> Out>;
 
 impl<Prev, Init, Func, Out> PullBuild for FoldEpochPullBuild<Prev, Init, Func>
diff --git a/hydroflow/src/builder/build/pull_map.rs b/hydroflow/src/builder/build/pull_map.rs
index e14d768b37a6..f4cdf9ee90ee 100644
--- a/hydroflow/src/builder/build/pull_map.rs
+++ b/hydroflow/src/builder/build/pull_map.rs
@@ -23,7 +23,7 @@ where
 type PullBuildImpl<'slf, 'ctx, Prev, Func, Out>
 where
     Prev: PullBuild,
-    Func: 'slf,
+    Func: 'slf + FnMut(&Context, Prev::ItemOut) -> Out,
 = std::iter::Map<Prev::Build<'slf, 'ctx>, impl FnMut(Prev::ItemOut) -> Out>;
 
 impl<Prev, Func, Out> PullBuild for MapPullBuild<Prev, Func>
diff --git a/hydroflow/src/builder/build/push_filter.rs b/hydroflow/src/builder/build/push_filter.rs
index 7309a79ce015..ac0631fd1f43 100644
--- a/hydroflow/src/builder/build/push_filter.rs
+++ b/hydroflow/src/builder/build/push_filter.rs
@@ -27,7 +27,7 @@ where
 type PushBuildImpl<'slf, 'ctx, Next, Func>
 where
     Next: PushBuild,
-    Func: 'slf,
+    Func: 'slf + FnMut(&Context, &Next::ItemIn) -> bool,
 = Filter<Next::ItemIn, impl FnMut(&Next::ItemIn) -> bool, Next::Build<'slf, 'ctx>>;
 
 impl<Next, Func> PushBuild for FilterPushBuild<Next, Func>
diff --git a/hydroflow/src/builder/build/push_filter_map.rs b/hydroflow/src/builder/build/push_filter_map.rs
index 19ec5dbf1951..a1a408a4ca7b 100644
--- a/hydroflow/src/builder/build/push_filter_map.rs
+++ b/hydroflow/src/builder/build/push_filter_map.rs
@@ -34,7 +34,7 @@ where
 type PushBuildImpl<'slf, 'ctx, Next, Func, In>
 where
     Next: PushBuild,
-    Func: 'slf,
+    Func: 'slf + FnMut(&Context, In) -> Option<Next::ItemIn>,
 = FilterMap<Next::Build<'slf, 'ctx>, impl FnMut(In) -> Option<Next::ItemIn>, In>;
 
 impl<Next, Func, In> PushBuild for FilterMapPushBuild<Next, Func, In>
diff --git a/hydroflow/src/builder/build/push_for_each.rs b/hydroflow/src/builder/build/push_for_each.rs
index aad5b420fbf1..bd1de1340705 100644
--- a/hydroflow/src/builder/build/push_for_each.rs
+++ b/hydroflow/src/builder/build/push_for_each.rs
@@ -30,7 +30,7 @@ where
 #[allow(type_alias_bounds)]
 type PushBuildImpl<'slf, 'ctx, Func, In>
 where
-    Func: 'slf,
+    Func: 'slf + FnMut(&Context, In),
 = ForEach<In, impl FnMut(In)>;
 
 impl<Func, In> PushBuild for ForEachPushBuild<Func, In>
diff --git a/hydroflow/src/builder/build/push_map.rs b/hydroflow/src/builder/build/push_map.rs
index 3e12d97e5a7c..3c275bb4f283 100644
--- a/hydroflow/src/builder/build/push_map.rs
+++ b/hydroflow/src/builder/build/push_map.rs
@@ -34,7 +34,7 @@ where
 type PushBuildImpl<'slf, 'ctx, Next, Func, In>
 where
     Next: PushBuild,
-    Func: 'slf,
+    Func: 'slf + FnMut(&Context, In) -> Next::ItemIn,
 = Map<In, Next::ItemIn, impl FnMut(In) -> Next::ItemIn, Next::Build<'slf, 'ctx>>;
 
 impl<Next, Func, In> PushBuild for MapPushBuild<Next, Func, In>
diff --git a/hydroflow/src/builder/build/push_partition.rs b/hydroflow/src/builder/build/push_partition.rs
index d29dc9f16cde..7fe9f38b1377 100644
--- a/hydroflow/src/builder/build/push_partition.rs
+++ b/hydroflow/src/builder/build/push_partition.rs
@@ -42,9 +42,13 @@ where
 #[allow(type_alias_bounds)]
 type PushBuildImpl<'slf, 'ctx, NextA, NextB, Func>
 where
+    Func: 'slf + FnMut(&Context, &NextA::ItemIn) -> bool,
     NextA: PushBuild,
     NextB: PushBuild<ItemIn = NextA::ItemIn>,
-    Func: 'slf,
+
+    NextA::OutputHandoffs: Extend<NextB::OutputHandoffs>,
+    <NextA::OutputHandoffs as Extend<NextB::OutputHandoffs>>::Extended:
+        PortList<SEND> + PortListSplit<SEND, NextA::OutputHandoffs, Suffix = NextB::OutputHandoffs>,
 = Partition<
     NextA::ItemIn,
     impl FnMut(&NextA::ItemIn) -> bool,
diff --git a/hydroflow/src/builder/surface/map_scan.rs b/hydroflow/src/builder/surface/map_scan.rs
index 5c9d83d69871..37974329e212 100644
--- a/hydroflow/src/builder/surface/map_scan.rs
+++ b/hydroflow/src/builder/surface/map_scan.rs
@@ -10,7 +10,11 @@ use crate::scheduled::context::Context;
 use crate::scheduled::flow_graph::NodeId;
 use crate::scheduled::state::StateHandle;
 
-type MapScanFunc<Func, State, In, Out> = impl FnMut(&Context, In) -> Out;
+type MapScanFunc<Func, State, In, Out>
+where
+    Func: FnMut(&mut State, In) -> Out,
+    State: Any,
+= impl FnMut(&Context, In) -> Out;
 
 fn wrap_func<Func, State, In, Out>(
     mut func: Func,
diff --git a/hydroflow/src/builder/surface/mod.rs b/hydroflow/src/builder/surface/mod.rs
index 6e3dce06f223..292d677c4bba 100644
--- a/hydroflow/src/builder/surface/mod.rs
+++ b/hydroflow/src/builder/surface/mod.rs
@@ -190,26 +190,31 @@ pub trait BaseSurface {
 pub type MapNoCtxFn<Prev, Func, Out>
 where
     Prev: BaseSurface,
+    Func: FnMut(Prev::ItemOut) -> Out,
 = impl FnMut(&Context, Prev::ItemOut) -> Out;
 
 pub type FilterNoCtxFn<Prev, Func>
 where
     Prev: BaseSurface,
+    Func: FnMut(&Prev::ItemOut) -> bool,
 = impl FnMut(&Context, &Prev::ItemOut) -> bool;
 
 pub type FilterMapNoCtxFn<Prev, Func, Out>
 where
     Prev: BaseSurface,
+    Func: FnMut(Prev::ItemOut) -> Option<Out>,
 = impl FnMut(&Context, Prev::ItemOut) -> Option<Out>;
 
 pub type InspectMapFunc<Prev, Func>
 where
     Prev: BaseSurface,
+    Func: FnMut(&Context, &Prev::ItemOut),
 = impl FnMut(&Context, Prev::ItemOut) -> Prev::ItemOut;
 
 pub type InspectMapNoCtxFunc<Prev, Func>
 where
     Prev: BaseSurface,
+    Func: FnMut(&Prev::ItemOut),
 = impl FnMut(&Context, Prev::ItemOut) -> Prev::ItemOut;
 
 pub trait PullSurface: BaseSurface {
@@ -443,12 +448,20 @@ pub trait PushSurface: BaseSurface {
 
 pub type ForEachNoCtxFunc<Prev, Func>
 where
-    Prev: BaseSurface,
+    Prev: PushSurface,
+    Func: FnMut(Prev::ItemOut),
 = impl FnMut(&Context, Prev::ItemOut);
 
 pub type PartitionNoCtxOutput<Prev, Func, NextA, NextB>
 where
-    Prev: BaseSurface,
+    Prev: PushSurface,
+    Func: Fn(&Prev::ItemOut) -> bool,
+    NextA: PushSurfaceReversed<ItemIn = Prev::ItemOut>,
+    NextB: PushSurfaceReversed<ItemIn = Prev::ItemOut>,
+
+    NextA::OutputHandoffs: Extend<NextB::OutputHandoffs>,
+    <NextA::OutputHandoffs as Extend<NextB::OutputHandoffs>>::Extended:
+        PortList<SEND> + PortListSplit<SEND, NextA::OutputHandoffs, Suffix = NextB::OutputHandoffs>,
 = push_partition::PartitionPushSurfaceReversed<
     NextA,
     NextB,