diff --git a/src/Lib/Types.newt b/src/Lib/Types.newt
index faa1061..6558bac 100644
--- a/src/Lib/Types.newt
+++ b/src/Lib/Types.newt
@@ -402,6 +402,7 @@ record ModContext where
   modMetaCtx : MetaContext
   -- longer term maybe drop this, put the operator decls in ctxDefs and collect them on import
   ctxOps : Operators
+  modDeps : List QName
 
 -- Top level context.
 -- Most of the reason this is separate is to have a different type
@@ -412,7 +413,7 @@ record ModContext where
 
 -- A placeholder while walking through dependencies of a module
 emptyModCtx : String → ModContext
-emptyModCtx csum = MkModCtx csum emptyMap (MC emptyMap Nil 0 NoCheck) emptyMap
+emptyModCtx csum = MkModCtx csum emptyMap (MC emptyMap Nil 0 NoCheck) emptyMap Nil
 
 HintTable : U
 HintTable = SortedMap QName (List (QName × Tm))
diff --git a/src/Main.newt b/src/Main.newt
index a48f0c3..eed682e 100644
--- a/src/Main.newt
+++ b/src/Main.newt
@@ -91,6 +91,9 @@ importHints (entry :: entries) = do
   when (elem Hint entry.eflags) $ \ _ => addHint entry.name
   importHints entries
 
+importToQN : Import → QName
+importToQN  (MkImport fc name') = uncurry QN $ unsnoc $ split1 name' "."
+
 -- New style loader, one def at a time
 processModule : FC -> String -> List String -> QName -> M String
 processModule importFC base stk qn@(QN ns nm) = do
@@ -120,6 +123,8 @@ processModule importFC base stk qn@(QN ns nm) = do
   let (Right (imports, ops, toks)) = partialParse fn parseImports ops toks
     | Left (err, toks) => exitFailure (showError src err)
 
+  let importNames = map importToQN imports
+
   imported <- for imports $ \case
     MkImport fc name' => do
       let (a,b) = unsnoc $ split1 name' "."
@@ -164,7 +169,7 @@ processModule importFC base stk qn@(QN ns nm) = do
   -- update modules with result, leave the rest of context in case this is top file
   top <- getTop
 
-  let mod = MkModCtx csum top.defs top.metaCtx top.ops
+  let mod = MkModCtx csum top.defs top.metaCtx top.ops importNames
   if stk /= Nil && length' top.errors == 0
     then dumpModule qn src mod
     else pure MkUnit
@@ -229,7 +234,7 @@ processFile fn = do
   setDef (QN primNS "PiType") emptyFC (Erased emptyFC) (PrimFn "(h0, h1) => ({ tag: \"PiType\", h0, h1 });" (S (S Z)) Nil) Nil
 
   top <- getTop
-  let modules = updateMap primNS (MkModCtx "" top.defs (MC emptyMap Nil 0 CheckAll) top.ops) top.modules
+  let modules = updateMap primNS (MkModCtx "" top.defs (MC emptyMap Nil 0 CheckAll) top.ops Nil) top.modules
   modifyTop (\ top => MkTop modules (primNS :: Nil) emptyMap Nil emptyMap top.metaCtx top.verbose top.errors top.ops)
 
   src <- processModule emptyFC base Nil qn
diff --git a/src/Serialize.newt b/src/Serialize.newt
index 65c95e2..49a214e 100644
--- a/src/Serialize.newt
+++ b/src/Serialize.newt
@@ -7,7 +7,7 @@ import Lib.Types
 import Data.SortedMap
 
 ModFile : U
-ModFile = (String × List TopEntry × List (String × OpDef) × List (QName × MetaEntry))
+ModFile = (String × List TopEntry × List (String × OpDef) × List (QName × MetaEntry) × List QName)
 
 pfunc checksum uses (MkIORes) : String → IO String := `(a) => (w) => {
   const arr = new TextEncoder().encode(a);
@@ -39,7 +39,8 @@ dumpModule qn src mod = do
   let defs = listValues mod.modDefs
   let ops = toList mod.ctxOps
   let mctx = toList mod.modMetaCtx.metas
-  liftIO $ dumpModFile fn (csum,defs,ops,mctx)
+  let deps = mod.modDeps
+  liftIO $ dumpModFile fn (csum,defs,ops,mctx, deps)
 
 pfunc readModFile uses (MkIORes Just Nothing): String → IO (Maybe ModFile) := `(fn) => (w) => {
   let fs = require('fs')
@@ -56,7 +57,7 @@ pfunc readModFile uses (MkIORes Just Nothing): String → IO (Maybe ModFile) :=
 loadModule : QName → String → M (Maybe ModContext)
 loadModule qn src = do
   let fn = "build/\{show qn}.newtmod"
-  (Just (csum, defs, ops, mctx)) <- liftIO {M} $ readModFile fn
+  (Just (csum, defs, ops, mctx, deps)) <- liftIO {M} $ readModFile fn
      | _ => pure Nothing
 
   let ops = mapFromList ops
@@ -64,5 +65,5 @@ loadModule qn src = do
       -- REVIEW can we ignore those last two inside a module
   let mctx = MC (mapFromList mctx) Nil 0 NoCheck
   if csum == src
-    then pure $ Just $ MkModCtx csum defs mctx ops
+    then pure $ Just $ MkModCtx csum defs mctx ops deps
     else pure Nothing