diff --git a/src/Renderer/TOC.hs b/src/Renderer/TOC.hs
index c9ba3e9d0..37ff47734 100644
--- a/src/Renderer/TOC.hs
+++ b/src/Renderer/TOC.hs
@@ -1,8 +1,62 @@
+{-# LANGUAGE ScopedTypeVariables #-}
 module Renderer.TOC where
 
+import Prologue
+import Patch
 import Renderer
 import Data.Record
 import Info
+import Data.Functor.Both hiding (fst, snd)
+import Source
+import Diff
+
+
+{-
+
+TOCSummary (Patch DiffInfo) [Identifiable (Category, Text), Annotatable]
+
+{
+  "changes": [
+    { FilePath: [ {SourceSpan, TermContext, TermType, ChangeType} ] }
+  ],
+  "errors": [
+    { FilePath: [ {SourceSpan, ErrorText } ] }
+  ]
+}
+-}
+
+data JSONSummary = JSONSummary { span :: SourceSpan, termContext :: Text, contextType :: Text, changeType :: Text }
+
+data DiffInfo = LeafInfo { leafCategory :: Category, termName :: Text, sourceSpan :: SourceSpan }
+ | BranchInfo { branches :: [ DiffInfo ], branchCategory :: Category }
+ | ErrorInfo { errorSpan :: SourceSpan, termName :: Text }
+ | HideInfo -- Hide/Strip from summary output entirely.
+ deriving (Eq, Show)
+
+data TOCSummary a = TOCSummary {
+  patch :: Patch a,
+  parentAnnotation :: [Either (Category, Text) (Category, Text)]
+} deriving (Eq, Functor, Show, Generic)
+
+toc :: (StringConv leaf Text, DefaultFields fields) => Both SourceBlob -> SyntaxDiff leaf fields -> [TOCSummary DiffInfo]
+toc blobs diff = tocToJSONSummaries =<< diffToTOC (source <$> blobs) diff
+
+diffToTOC :: (StringConv leaf Text, DefaultFields fields) => Both (Source Char) -> SyntaxDiff leaf fields -> [TOCSummary DiffInfo]
+diffToTOC = _
+
+tocToJSONSummaries :: TOCSummary DiffInfo -> [JSONSummary]
+tocToJSONSummaries TOCSummary{..} =
+
+-- If the term is a method/function grab the term type, name, and span here, otherwise grab them up top.
+summaries :: Patch DiffInfo -> [TOCSummary (Maybe Text) (Maybe Text) (Maybe SourceSpans)]
+summaries = \case
+  p@(Replace i1 i2) -> zipWith (\a b ->
+    TOCSummary
+     {
+      changeType = "replace"
+      termContext =
+    , span = SourceSpans $ These (span a) (span b)
+    }) (toLeafInfos i1) (toLeafInfos i2)
+  p@(Insert info) -> prefixWithPatch p That <$> toLeafInfos info
+  p@(Delete info) -> prefixWithPatch p This <$> toLeafInfos info
 
-toc :: (HasField fields Category, HasField fields Cost, HasField fields Range) => Renderer (Record fields)
-toc sources diff = TOCOutput []
\ No newline at end of file