diff --git a/src/Unison/Edit/Term/Path.hs b/src/Unison/Edit/Term/Path.hs
index e4632bf04..01ae0a50d 100644
--- a/src/Unison/Edit/Term/Path.hs
+++ b/src/Unison/Edit/Term/Path.hs
@@ -3,7 +3,10 @@ module Unison.Edit.Term.Path where
 import qualified Unison.Syntax.Term as E
 import Control.Applicative
 
-data E = Fn | Arg | Body
+data E
+  = Fn -- ^ Points at function in a function application
+  | Arg -- ^ Points at the argument of a function application
+  | Body -- ^ Points at the body of a lambda
 
 newtype Path = Path [E]
 
diff --git a/src/Unison/Edit/Type/Path.hs b/src/Unison/Edit/Type/Path.hs
new file mode 100644
index 000000000..d7ce8587b
--- /dev/null
+++ b/src/Unison/Edit/Type/Path.hs
@@ -0,0 +1,6 @@
+module Unison.Edit.Type.Path where
+
+-- | Represents a path into an ADT. We choose which numbered constructor,
+-- and then which argument of that constructor we are addressing, where
+-- @0@ denotes the overall constructor itself.
+data Path = Path { constructor :: !Int, arg :: !Int }
diff --git a/src/Unison/Node.hs b/src/Unison/Node.hs
index 89476c5d9..499138df7 100644
--- a/src/Unison/Node.hs
+++ b/src/Unison/Node.hs
@@ -1,16 +1,53 @@
 module Unison.Node where
 
+import Data.Set as S
+import Data.Text
 import Unison.Node.Panel
 import Unison.Node.Metadata as M
+import Unison.Edit.Term.Action as A
+import Unison.Edit.Term.Path as P
+import Unison.Edit.Type.Path as TP
+import Unison.Type.Note as N
 
 data Node m k t e = Node {
-  term :: k -> m (Maybe e), -- ^ Lookup the source of the term identified by @k@
-  typ :: k -> m (Maybe t), -- ^ Lookup the source of the type identified by @k@
-  metadata :: k -> m (Maybe (M.Metadata k)), -- ^ Access the metadata for the term or type identified by @k@
-  panel :: k -> m (Maybe (Panel k t e)) -- ^ Render the term or type identified by @k@ as a panel
+  -- | Create a new term and provide its metadata
+  createTerm :: e -> M.Metadata k -> m k,
+  -- | Create a new type and provide its metadata
+  createType :: t -> M.Metadata k -> m k,
+  -- | Lookup the direct dependencies of @k@, optionally limited to the given set
+  dependencies :: Maybe (S.Set k) -> k -> m (S.Set k),
+  -- | Lookup the set of terms/types depending directly on the given @k@, optionally limited to the given set
+  dependents :: Maybe (S.Set k) -> k -> m (S.Set k),
+  -- | Modify the given subterm, which may fail
+  edit :: k -> P.Path -> A.Action k -> m (Either N.Note (k, e)),
+  -- | Modify the given type, which may fail
+  editType :: k -> P.Path -> A.Action k -> m (Either N.Note (k, t)),
+  -- | Access the metadata for the term or type identified by @k@
+  metadata :: k -> m (Maybe (M.Metadata k)),
+  -- | Render the term or type identified by @k@ as a panel--
+  panel :: k -> m (Maybe (Panel k t e)),
+  -- | Lookup a term by name, optionally constrained to be of the given type
+  search :: Maybe t -> Query -> m [(k, Metadata k)],
+  -- | Lookup the source of the term identified by @k@
+  term :: k -> m (Maybe e),
+  -- | Lookup the dependencies of @k@, optionally limited to those that intersect the given set
+  transitiveDependencies :: Maybe (S.Set k) -> k -> m (S.Set k),
+  -- | Lookup the set of terms or types which depend on the given @k@, optionally limited to those that intersect the given set
+  transitiveDependents :: Maybe (S.Set k) -> k -> m (S.Set k),
+  -- | Lookup the source of the type identified by @k@
+  typ :: k -> m (Maybe t),
+  -- | Obtain the type of the given subterm, assuming the path is valid
+  typeOf :: k -> P.Path -> m (Maybe t),
+  -- | Obtain the type of a constructor argument of a type
+  typeOfConstructorArg :: k -> TP.Path -> m (Maybe t),
+  -- | Update the metadata associated with the given term or type
+  updateMetadata :: k -> M.Metadata k -> m Bool
 
-  -- editing, creating terms and types
-  -- evaluation
+  -- possibly later
+  -- editConstructor :: k -> -> A.Action -> m (Either N.Note (k, t)), -- ^ Modify the given type, which may fail
+  -- examples :: k -> m (Maybe [k]), -- ^
 }
 
+data Query = Query Text
+
 
diff --git a/todo.markdown b/todo.markdown
index ca4f5f378..c1908b45c 100644
--- a/todo.markdown
+++ b/todo.markdown
@@ -1,3 +1,18 @@
 testing of typechecker
 editing combinators
 editor backend
+
+
+-- a layout tree uses hashes, not names
+-- merely a convention of the editor that it
+-- transitively updates dependent hashes
+-- that is, given:
+-- y = 42
+-- f x = x + y
+-- the editor just adopts the convention that
+-- updating `y` will update `f` to point to the
+-- new hash of the thing called `y`, rather than
+-- continuing to point at old hash
+--
+
+-- need path and action type for ADTs
diff --git a/unison.cabal b/unison.cabal
index 7fe4b1c47..8ef33825a 100644
--- a/unison.cabal
+++ b/unison.cabal
@@ -51,6 +51,7 @@ library
     Unison.Edit.Term.Movement
     Unison.Edit.Term.Path
     Unison.Edit.Term.Edit
+    Unison.Edit.Type.Path
     Unison.Edit.Layout
     Unison.Edit.Layout.Style
     Unison.Node