From b9f353dd8af69ea8ec14389e36e81cc786a457b3 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sat, 1 Nov 2025 17:55:02 +1000
Subject: [PATCH 01/41] amazonka: Generate and store idempotency tokens into
 requests

---
 lib/amazonka-core/src/Amazonka/Types.hs | 12 +++++++++++-
 lib/amazonka/CHANGELOG.md               |  3 +++
 lib/amazonka/src/Amazonka/HTTP.hs       | 16 ++++++++++++----
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/lib/amazonka-core/src/Amazonka/Types.hs b/lib/amazonka-core/src/Amazonka/Types.hs
index be0b3a63b43..20501dfac03 100644
--- a/lib/amazonka-core/src/Amazonka/Types.hs
+++ b/lib/amazonka-core/src/Amazonka/Types.hs
@@ -677,6 +677,17 @@ class (Typeable a, Typeable (AWSResponse a)) => AWSRequest a where
     ClientResponse ClientBody ->
     m (Either Error (ClientResponse (AWSResponse a)))
 
+  -- | For some requests, botocore will designate one field of a
+  -- request as an "idempotency token", which the caller can manually
+  -- fill in to defend against deduplication. If he does not, it needs
+  -- to be filled in by the SDK.
+  --
+  -- This is a 'Lens.LensLike'' and not a true 'Lens.Lens'' because if
+  -- the request type does not contain an idempotency token, it will
+  -- do nothing (violating the get/set law).
+  updateIdempotencyToken ::
+    (Functor f) => Lens.LensLike' f a (Maybe Text)
+
 -- | An access key ID.
 --
 -- For example: @AKIAIOSFODNN7EXAMPLE@
@@ -952,7 +963,6 @@ pattern TelAviv = Region' "il-central-1"
 pattern MexicoCentral :: Region
 pattern MexicoCentral = Region' "mx-central-1"
 
-
 -- Middle East
 
 pattern Bahrain :: Region
diff --git a/lib/amazonka/CHANGELOG.md b/lib/amazonka/CHANGELOG.md
index 8ba53a67423..c328efc7045 100644
--- a/lib/amazonka/CHANGELOG.md
+++ b/lib/amazonka/CHANGELOG.md
@@ -4,6 +4,9 @@
 
 ### Changed
 
+- `amazonka` will now store idempotency tokens into requests that support them but have not been set by the caller.
+  - `amazonka-core`: Class `AWSRequest` has an new function `updateIdempotencyToken`. If a request type can contain an idempotency token, this function will allow it to be updated.
+
 - `amazonka`: Improve error handling during periodic credential refresh in `fetchAuthInBackground`.
   Exceptions thrown by the refresh action are now categorized and rethrown to the parent thread as
   `RetrievalError`, `AuthServiceError`, or `OtherAuthError` (instead of just `RetrievalError` which was a bug). (thanks @kushagarr)
diff --git a/lib/amazonka/src/Amazonka/HTTP.hs b/lib/amazonka/src/Amazonka/HTTP.hs
index 8640ff0f6fa..0d81058be05 100644
--- a/lib/amazonka/src/Amazonka/HTTP.hs
+++ b/lib/amazonka/src/Amazonka/HTTP.hs
@@ -28,6 +28,8 @@ import Control.Monad.Trans.Resource (liftResourceT, transResourceT)
 import qualified Control.Retry as Retry
 import Data.Foldable (traverse_)
 import qualified Data.Time as Time
+import qualified Data.UUID as UUID
+import qualified Data.UUID.V4 as UUIDv4
 import qualified Network.HTTP.Conduit as Client.Conduit
 
 retryRequest ::
@@ -152,10 +154,16 @@ httpRequest env@Env {hooks, manager, region} cfgRq =
 -- (Request a).
 configureRequest ::
   (AWSRequest a, MonadIO m) => Env' withAuth -> a -> m (Request a)
-configureRequest env@Env {overrides, hooks} =
-  liftIO
-    . Hooks.configuredRequest hooks env
-    . request overrides
+configureRequest env@Env {overrides, hooks} awsRequest = do
+  -- If the idempotency token is not set, create a v4 UUID
+  -- for consistency with botocore:
+  -- https://github.com/boto/botocore/blob/1122d80bfeb3a52a7ae7138a9e9abdb538eae895/botocore/handlers.py#L285
+  let uuidV4IfAbsent = \case
+        Nothing -> liftIO $ Just . UUID.toText <$> UUIDv4.nextRandom
+        Just token -> pure $ Just token
+  configuredRequest <-
+    request overrides <$> updateIdempotencyToken uuidV4IfAbsent awsRequest
+  liftIO $ Hooks.configuredRequest hooks env configuredRequest
 
 retryStream :: Request a -> Retry.RetryPolicy
 retryStream Request {body} =

From 238c06b33c83b494273e1ed508a849c033b7d3cc Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sun, 9 Nov 2025 07:39:48 +1000
Subject: [PATCH 02/41] gen: Make instance FromJSON (RefF ()) explicit

---
 gen/src/Gen/Types/Service.hs | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/gen/src/Gen/Types/Service.hs b/gen/src/Gen/Types/Service.hs
index e878c323d4f..4b33c3d6a7c 100644
--- a/gen/src/Gen/Types/Service.hs
+++ b/gen/src/Gen/Types/Service.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE ApplicativeDo #-}
 {-# LANGUAGE TemplateHaskell #-}
 
 module Gen.Types.Service where
@@ -141,17 +142,18 @@ instance HasId (RefF a) where
   identifier = identifier . _refShape
 
 instance FromJSON (RefF ()) where
-  parseJSON = Aeson.withObject "ref" $ \o ->
-    RefF ()
-      <$> o .: "shape"
-      <*> o .:? "documentation"
-      <*> o .:? "location"
-      <*> o .:? "locationName"
-      <*> o .:? "resultWrapper"
-      <*> o .:? "queryName"
-      <*> o .:? "streaming" .!= False
-      <*> o .:? "xmlAttribute" .!= False
-      <*> o .:? "xmlNamespace"
+  parseJSON = Aeson.withObject "ref" $ \o -> do
+    let _refAnn = ()
+    _refShape <- o .: "shape"
+    _refDocumentation <- o .:? "documentation"
+    _refLocation <- o .:? "location"
+    _refLocationName <- o .:? "locationName"
+    _refResultWrapper <- o .:? "resultWrapper"
+    _refQueryName <- o .:? "queryName"
+    _refStreaming <- o .:? "streaming" .!= False
+    _refXMLAttribute <- o .:? "xmlAttribute" .!= False
+    _refXMLNamespace <- o .:? "xmlNamespace"
+    pure RefF {..}
 
 class HasRefs f where
   references :: Lens.Traversal (f a) (f b) (RefF a) (RefF b)
@@ -198,7 +200,7 @@ instance FromJSON Info where
       <*> o .:? "exception" .!= False
       <*> o .:? "error"
 
-nonEmpty :: HasInfo a => a -> Bool
+nonEmpty :: (HasInfo a) => a -> Bool
 nonEmpty = (> Just 0) . Lens.view infoMin
 
 data ListF a = ListF
@@ -354,7 +356,7 @@ $(Lens.makeLenses ''Operation)
 operationNS :: NS -> Id -> NS
 operationNS ns = mappend ns . mkNS . typeId
 
-inputName, outputName :: HasId a => Operation Identity a b -> Id
+inputName, outputName :: (HasId a) => Operation Identity a b -> Id
 inputName = identifier . Lens.view (opInput . _Identity)
 outputName = identifier . Lens.view (opOutput . _Identity)
 
@@ -372,7 +374,7 @@ instance FromJSON (Operation Maybe (RefF ()) ()) where
       <*> o .:? "output"
       <*> pure Nothing
 
-instance ToJSON a => ToJSON (Operation Identity a b) where
+instance (ToJSON a) => ToJSON (Operation Identity a b) where
   toJSON o =
     Aeson.object
       [ "name" .= (o ^. opName),
@@ -423,7 +425,7 @@ instance FromJSON (Metadata Maybe) where
 instance ToJSON (Metadata Identity) where
   toJSON = gToJSON' camel
 
-serviceError :: HasMetadata a f => a -> Text
+serviceError :: (HasMetadata a f) => a -> Text
 serviceError m =
   case m ^. protocol of
     JSON -> "parseJSONError"
@@ -472,7 +474,7 @@ type Ref = RefF (Shape Solved)
 
 class IsStreaming a where
   isStreaming :: a -> Bool
-  default isStreaming :: HasInfo a => a -> Bool
+  default isStreaming :: (HasInfo a) => a -> Bool
   isStreaming = Lens.view infoStreaming
 
 instance IsStreaming Info
@@ -483,7 +485,7 @@ instance IsStreaming (ShapeF a)
 
 instance IsStreaming (Shape a)
 
-instance IsStreaming a => IsStreaming (RefF a) where
+instance (IsStreaming a) => IsStreaming (RefF a) where
   isStreaming r = _refStreaming r || isStreaming (_refAnn r)
 
 instance IsStreaming TType where

From 91fae37c7cf519034cf2e935f4725b47a7ab1b73 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Mon, 10 Nov 2025 06:50:45 +1000
Subject: [PATCH 03/41] gen: Remove redundant case

---
 gen/src/Gen/AST/Data/Syntax.hs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/gen/src/Gen/AST/Data/Syntax.hs b/gen/src/Gen/AST/Data/Syntax.hs
index ab61094ab1c..78c927ed35c 100644
--- a/gen/src/Gen/AST/Data/Syntax.hs
+++ b/gen/src/Gen/AST/Data/Syntax.hs
@@ -181,7 +181,6 @@ recordD :: (HasMetadata a Identity) => a -> Id -> [Field] -> QualConDecl
 recordD m n =
   conD . \case
     [] -> Exts.ConDecl () c []
-    [x] -> Exts.RecDecl () c [fieldDecl (internal m) x]
     xs -> Exts.RecDecl () c (map (fieldDecl (internal m)) xs)
   where
     fieldDecl h f = Exts.FieldDecl () [ident (fieldAccessor f)] (h f)

From ed3a590a12e6eae13c768074919991680b7f9a3c Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Mon, 10 Nov 2025 06:58:57 +1000
Subject: [PATCH 04/41] amazonka-core: typo

---
 lib/amazonka-core/test/Test/Amazonka/Sign/V4.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/amazonka-core/test/Test/Amazonka/Sign/V4.hs b/lib/amazonka-core/test/Test/Amazonka/Sign/V4.hs
index 287228bd460..c0f00a2496c 100644
--- a/lib/amazonka-core/test/Test/Amazonka/Sign/V4.hs
+++ b/lib/amazonka-core/test/Test/Amazonka/Sign/V4.hs
@@ -1,5 +1,5 @@
 -- |
--- Module      : Test.Amazonka.Sign.V$
+-- Module      : Test.Amazonka.Sign.V4
 -- Copyright   : (c) 2013-2023 Brendan Hay
 -- License     : Mozilla Public License, v. 2.0.
 -- Maintainer  : Brendan Hay <brendan.g.hay+amazonka@gmail.com>

From 61a2c5d4da0d968761bd7a705eab7b2d59b68531 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Mon, 10 Nov 2025 07:14:07 +1000
Subject: [PATCH 05/41] gen: Rename some fields for clarity

---
 gen/src/Gen/AST/Data/Syntax.hs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/gen/src/Gen/AST/Data/Syntax.hs b/gen/src/Gen/AST/Data/Syntax.hs
index 78c927ed35c..38a9c8bb90f 100644
--- a/gen/src/Gen/AST/Data/Syntax.hs
+++ b/gen/src/Gen/AST/Data/Syntax.hs
@@ -360,14 +360,14 @@ requestD ::
   (Ref, [Inst]) ->
   (Ref, [Field]) ->
   Decl
-requestD c m h (a, as) (b, bs) =
+requestD c m h (requestRef, requestInstances) (responseRef, responseFields) =
   instD
     "Core.AWSRequest"
-    (identifier a)
+    (identifier requestRef)
     $ Just
-      [ assocD (identifier a) "AWSResponse" (typeId (identifier b)),
-        funArgsD "request" ["overrides"] (requestF c m h a as),
-        funD "response" (responseE (m ^. protocol) b bs)
+      [ assocD (identifier requestRef) "AWSResponse" (typeId (identifier responseRef)),
+        funArgsD "request" ["overrides"] (requestF c m h requestRef requestInstances),
+        funD "response" (responseE (m ^. protocol) responseRef responseFields)
       ]
 
 responseE :: Protocol -> Ref -> [Field] -> Exp

From a05717e3e429edbb4d49bcb25edfe92797610766 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Mon, 10 Nov 2025 07:49:57 +1000
Subject: [PATCH 06/41] gen: Extrace AWSRequest generation into its own module

---
 gen/amazonka-gen.cabal                    |   1 +
 gen/src/Gen/AST/Data.hs                   |   3 +-
 gen/src/Gen/AST/Data/Instance.hs          |  55 +++---
 gen/src/Gen/AST/Data/Syntax.hs            | 161 ------------------
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 193 ++++++++++++++++++++++
 5 files changed, 224 insertions(+), 189 deletions(-)
 create mode 100644 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs

diff --git a/gen/amazonka-gen.cabal b/gen/amazonka-gen.cabal
index f735ac54ab1..2d73e2d30f2 100644
--- a/gen/amazonka-gen.cabal
+++ b/gen/amazonka-gen.cabal
@@ -95,6 +95,7 @@ library
     Gen.AST.Data.Field
     Gen.AST.Data.Instance
     Gen.AST.Data.Syntax
+    Gen.AST.Data.Syntax.AWSRequest
     Gen.AST.Override
     Gen.AST.Prefix
     Gen.AST.Subst
diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index bba4c265a76..e0d0ef4117d 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -21,6 +21,7 @@ import qualified Data.Text.Lazy as Text.Lazy
 import Gen.AST.Data.Field
 import Gen.AST.Data.Instance
 import Gen.AST.Data.Syntax as Syntax
+import qualified Gen.AST.Data.Syntax.AWSRequest as AWSRequest
 import Gen.Prelude
 import Gen.Types
 import qualified Language.Haskell.Exts as Exts
@@ -41,7 +42,7 @@ operationData cfg m o = do
 
   xis <- addInstances xa xs <$> requestInsts m (_opName o) h xr xs
 
-  cls <- pp Print $ requestD cfg m h (xr, xis) (yr, ys)
+  cls <- pp Print $ AWSRequest.instanceD cfg m h (xr, xis) (yr, ys)
   mpage <- pagerFields m o >>= traverse (pp Print . pagerD xn)
 
   yis' <- renderInsts p yn (responseInsts ys)
diff --git a/gen/src/Gen/AST/Data/Instance.hs b/gen/src/Gen/AST/Data/Instance.hs
index 95b26ef81d5..7f74294f541 100644
--- a/gen/src/Gen/AST/Data/Instance.hs
+++ b/gen/src/Gen/AST/Data/Instance.hs
@@ -20,6 +20,7 @@ data Inst
   | ToBody Field
   | IsHashable [Field]
   | IsNFData [Field]
+  deriving (Show)
 
 instance ToJSON Inst where
   toJSON = Aeson.toJSON . instToText
@@ -91,7 +92,7 @@ responseInsts fs
     (not . null -> stream, _) = List.partition fieldStream (notLocated fs)
 
 requestInsts ::
-  HasMetadata a f =>
+  (HasMetadata a f) =>
   a ->
   Id ->
   HTTP ->
@@ -142,32 +143,32 @@ requestInsts m oname h r fs = do
     replaceXML is
       | all nonEmptyXML is = pure $! filter anyXML is
       | otherwise =
-        case ( r ^? refXMLNamespace . Lens._Just . xmlUri,
-               r ^. refLocationName,
-               listToMaybe (mapMaybe findElement is)
-             ) of
-          -- 1. If there's an xmlNamespace and/or locationName on the ref,
-          --    it should define separate ToXML + ToElement instances
-          (ns, Just e, _) ->
-            pure $! ToElement (ns <|> m ^. xmlNamespace) (Left e) : is
-          -- 2. Otherwise, a single field should be found in the ToXML instance
-          -- and lifted to a single ToElement instance.
-          (_, _, Just f) ->
-            pure $! ToElement ns (Right f) : filter anyXML is
-            where
-              ns =
-                m ^. xmlNamespace
-                  <|> f ^? fieldRef . refXMLNamespace . Lens._Just . xmlUri
-
-          -- 3. Unknown.
-          (ns, e, _) ->
-            Left $
-              "String determining root ToElement instance: "
-                ++ Text.unpack (memberId n)
-                ++ ", namespace: "
-                ++ show ns
-                ++ ", locationName: "
-                ++ show e
+          case ( r ^? refXMLNamespace . Lens._Just . xmlUri,
+                 r ^. refLocationName,
+                 listToMaybe (mapMaybe findElement is)
+               ) of
+            -- 1. If there's an xmlNamespace and/or locationName on the ref,
+            --    it should define separate ToXML + ToElement instances
+            (ns, Just e, _) ->
+              pure $! ToElement (ns <|> m ^. xmlNamespace) (Left e) : is
+            -- 2. Otherwise, a single field should be found in the ToXML instance
+            -- and lifted to a single ToElement instance.
+            (_, _, Just f) ->
+              pure $! ToElement ns (Right f) : filter anyXML is
+              where
+                ns =
+                  m ^. xmlNamespace
+                    <|> f ^? fieldRef . refXMLNamespace . Lens._Just . xmlUri
+
+            -- 3. Unknown.
+            (ns, e, _) ->
+              Left $
+                "String determining root ToElement instance: "
+                  ++ Text.unpack (memberId n)
+                  ++ ", namespace: "
+                  ++ show ns
+                  ++ ", locationName: "
+                  ++ show e
       where
         nonEmptyXML = notXML True
         anyXML = notXML False
diff --git a/gen/src/Gen/AST/Data/Syntax.hs b/gen/src/Gen/AST/Data/Syntax.hs
index 38a9c8bb90f..1d455e4be34 100644
--- a/gen/src/Gen/AST/Data/Syntax.hs
+++ b/gen/src/Gen/AST/Data/Syntax.hs
@@ -2,7 +2,6 @@
 
 module Gen.AST.Data.Syntax where
 
-import qualified Control.Comonad as Comonad
 import qualified Control.Lens as Lens
 import qualified Data.Char as Char
 import qualified Data.Foldable as Fold
@@ -352,88 +351,6 @@ notationE' withLensIso = \case
       TMaybe x -> var "Lens._Just" : lensIso x
       _other -> []
 
-requestD ::
-  (HasMetadata a Identity) =>
-  Config ->
-  a ->
-  HTTP ->
-  (Ref, [Inst]) ->
-  (Ref, [Field]) ->
-  Decl
-requestD c m h (requestRef, requestInstances) (responseRef, responseFields) =
-  instD
-    "Core.AWSRequest"
-    (identifier requestRef)
-    $ Just
-      [ assocD (identifier requestRef) "AWSResponse" (typeId (identifier responseRef)),
-        funArgsD "request" ["overrides"] (requestF c m h requestRef requestInstances),
-        funD "response" (responseE (m ^. protocol) responseRef responseFields)
-      ]
-
-responseE :: Protocol -> Ref -> [Field] -> Exp
-responseE p r fs = Exts.app (responseF p r fs) bdy
-  where
-    n = r ^. Lens.to identifier
-    s = r ^. refAnn . Lens.to Comonad.extract
-
-    bdy :: Exp
-    bdy
-      | null fs = var (ctorId n)
-      | isShared s, all fieldBody fs = lam parseAll
-      | otherwise = lam . ctorE n $ map parseField fs
-
-    lam :: Exp -> Exp
-    lam = Exts.lamE [Exts.pvar "s", Exts.pvar "h", Exts.pvar "x"]
-
-    parseField :: Field -> Exp
-    parseField x =
-      case fieldLocation x of
-        Just Headers -> parseHeadersE p x
-        Just Header -> parseHeadersE p x
-        Just StatusCode -> parseStatusE x
-        Just Body | body -> Exts.app pureE (var "x")
-        Nothing | body -> Exts.app pureE (var "x")
-        _ -> parseProto x
-
-    parseProto :: Field -> Exp
-    parseProto f =
-      case p of
-        _ | f ^. fieldPayload -> parseOne f
-        JSON -> parseJSONE p pJE pJEMay pJEDef f
-        RestJSON -> parseJSONE p pJE pJEMay pJEDef f
-        APIGateway -> parseJSONE p pJE pJEMay pJEDef f
-        _ -> parseXMLE p f
-
-    parseOne :: Field -> Exp
-    parseOne f
-      | fieldLit f =
-          if fieldIsParam f
-            then Exts.app (var "Prelude.pure") (var "x")
-            else -- Coerce is inserted here to handle newtypes such as Sensitive.
-
-              Exts.app (var "Prelude.pure")
-                . Exts.paren
-                . Exts.app justE
-                . Exts.paren
-                . Exts.app (var "Prelude.coerce")
-                $ var "x"
-      -- This ensures anything which is set as a payload,
-      -- but is a primitive type is just consumed as a bytestring.
-      | otherwise = parseAll
-
-    parseAll :: Exp
-    parseAll =
-      flip Exts.app (var "x") $
-        if any fieldLitPayload fs
-          then var "Prelude.pure"
-          else case p of
-            JSON -> var "Data.eitherParseJSON"
-            RestJSON -> var "Data.eitherParseJSON"
-            APIGateway -> var "Data.eitherParseJSON"
-            _ -> var "Data.parseXML"
-
-    body = any fieldStream fs
-
 instanceD :: Protocol -> Id -> Inst -> Decl
 instanceD p n = \case
   FromXML fs -> fromXMLD p n fs
@@ -594,9 +511,6 @@ funArgsD f as e =
   Exts.InsDecl () $
     Exts.sfun (ident f) (map ident as) (unguarded e) Exts.noBinds
 
-assocD :: Id -> Text -> Text -> InstDecl
-assocD n x y = Exts.InsType () (tyapp (tycon x) (tycon (typeId n))) (tycon y)
-
 decodeD :: Text -> Id -> Text -> ([a] -> Exp) -> [a] -> Decl
 decodeD c n f dec =
   instD1 c n . \case
@@ -649,22 +563,6 @@ parseJSONE p d dm dd f
     n = memberName p Output f
     x = var "x"
 
-parseHeadersE :: Protocol -> Field -> Exp
-parseHeadersE p f
-  | TMap {} <- typeOf f = Exts.appFun pHMap [str n, h]
-  | fieldMaybe f = decodeE h pHMay n
-  | otherwise = decodeE h pH n
-  where
-    n = memberName p Output f
-    h = var "h"
-
-parseStatusE :: Field -> Exp
-parseStatusE f
-  | fieldMaybe f = Exts.app pureE (Exts.app justE v)
-  | otherwise = Exts.app pureE v
-  where
-    v = Exts.paren $ Exts.app (var "Prelude.fromEnum") (var "s")
-
 toXMLE :: Protocol -> Field -> Exp
 toXMLE p f = toGenericE p opX "Data.toXML" toXMap toXList f
   where
@@ -785,65 +683,6 @@ inputNames, outputNames :: Protocol -> Field -> Names
 inputNames p f = Proto.nestedNames p Input (f ^. fieldId) (f ^. fieldRef)
 outputNames p f = Proto.nestedNames p Output (f ^. fieldId) (f ^. fieldRef)
 
-requestF ::
-  (HasMetadata a Identity) =>
-  Config ->
-  a ->
-  HTTP ->
-  Ref ->
-  [Inst] ->
-  Exp
-requestF c meta h r is =
-  maybe e (foldr applyPlugin e) selectedPlugins
-  where
-    applyPlugin x =
-      -- Plugin functions are of the form :: Request a -> Request a
-      Exts.infixApp (var x) "Prelude.."
-
-    selectedPlugins =
-      -- Lookup a specific operationPlugins key before the wildcard.
-      HashMap.lookup (identifier r) (c ^. operationPlugins)
-        <|> HashMap.lookup (mkId "*") (c ^. operationPlugins)
-
-    e = Exts.app v (Exts.app (var "overrides") (var $ meta ^. serviceConfig))
-
-    v =
-      var
-        . mappend ("Request." <> methodToText m)
-        . fromMaybe mempty
-        . listToMaybe
-        $ mapMaybe f is
-
-    f = \case
-      ToBody {} -> Just "Body"
-      ToJSON {} -> Just "JSON"
-      ToElement {} -> Just "XML"
-      _
-        | p == Query,
-          m == POST ->
-            Just "Query"
-      _
-        | p == EC2,
-          m == POST ->
-            Just "Query"
-      _ -> Nothing
-
-    m = h ^. method
-    p = meta ^. protocol
-
--- FIXME: take method into account for responses, such as HEAD etc, particuarly
--- when the body might be totally empty.
-responseF :: Protocol -> RefF a -> [Field] -> Exp
-responseF p r fs
-  | null fs = var "Response.receiveNull"
-  | any fieldStream fs = var "Response.receiveBody"
-  | any fieldLitPayload fs = var "Response.receiveBytes"
-  | Just x <- r ^. refResultWrapper = Exts.app (var (suf <> "Wrapper")) (str x)
-  | not $ any fieldBody fs = var "Response.receiveEmpty"
-  | otherwise = var suf
-  where
-    suf = "Response.receive" <> Proto.suffix p
-
 waiterS :: Id -> Waiter a -> Decl
 waiterS n w = Exts.TypeSig () [ident c] $ tyapp (tycon "Core.Wait") (tycon k)
   where
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
new file mode 100644
index 00000000000..157209b9a02
--- /dev/null
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -0,0 +1,193 @@
+module Gen.AST.Data.Syntax.AWSRequest where
+
+import qualified Control.Comonad as Comonad
+import qualified Control.Lens as Lens
+import qualified Data.HashMap.Strict as HashMap
+import Gen.AST.Data.Field (Field, fieldBody, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
+import Gen.AST.Data.Instance (Inst (..))
+import Gen.AST.Data.Syntax
+  ( ctorE,
+    decodeE,
+    funArgsD,
+    funD,
+    instD,
+    justE,
+    memberName,
+    pH,
+    pHMap,
+    pHMay,
+    pJE,
+    pJEDef,
+    pJEMay,
+    parseJSONE,
+    parseXMLE,
+    pureE,
+    str,
+    tyapp,
+    tycon,
+    var,
+  )
+import Gen.Prelude
+import qualified Gen.Protocol as Proto
+import Gen.Types
+import qualified Language.Haskell.Exts as Exts
+
+instanceD ::
+  (HasMetadata a Identity) =>
+  Config ->
+  a ->
+  HTTP ->
+  (Ref, [Inst]) ->
+  (Ref, [Field]) ->
+  Exts.Decl ()
+instanceD c m h (requestRef, requestInstances) (responseRef, responseFields) =
+  instD
+    "Core.AWSRequest"
+    (identifier requestRef)
+    $ Just
+      [ assocD (identifier requestRef) "AWSResponse" (typeId (identifier responseRef)),
+        funArgsD "request" ["overrides"] (requestF c m h requestRef requestInstances),
+        funD "response" (responseE (m ^. protocol) responseRef responseFields)
+      ]
+
+assocD :: Id -> Text -> Text -> Exts.InstDecl ()
+assocD n x y = Exts.InsType () (tyapp (tycon x) (tycon (typeId n))) (tycon y)
+
+requestF ::
+  (HasMetadata a Identity) =>
+  Config ->
+  a ->
+  HTTP ->
+  Ref ->
+  [Inst] ->
+  Exts.Exp ()
+requestF c meta h r is =
+  maybe e (foldr applyPlugin e) selectedPlugins
+  where
+    applyPlugin x =
+      -- Plugin functions are of the form :: Request a -> Request a
+      Exts.infixApp (var x) "Prelude.."
+
+    selectedPlugins =
+      -- Lookup a specific operationPlugins key before the wildcard.
+      HashMap.lookup (identifier r) (c ^. operationPlugins)
+        <|> HashMap.lookup (mkId "*") (c ^. operationPlugins)
+
+    e = Exts.app v (Exts.app (var "overrides") (var $ meta ^. serviceConfig))
+
+    v =
+      var
+        . mappend ("Request." <> methodToText m)
+        . fromMaybe mempty
+        . listToMaybe
+        $ mapMaybe f is
+
+    f = \case
+      ToBody {} -> Just "Body"
+      ToJSON {} -> Just "JSON"
+      ToElement {} -> Just "XML"
+      _
+        | p == Query,
+          m == POST ->
+            Just "Query"
+      _
+        | p == EC2,
+          m == POST ->
+            Just "Query"
+      _ -> Nothing
+
+    m = h ^. method
+    p = meta ^. protocol
+
+responseE :: Protocol -> Ref -> [Field] -> Exts.Exp ()
+responseE p r fs = Exts.app (responseF p r fs) bdy
+  where
+    n = r ^. Lens.to identifier
+    s = r ^. refAnn . Lens.to Comonad.extract
+
+    bdy :: Exts.Exp ()
+    bdy
+      | null fs = var (ctorId n)
+      | isShared s, all fieldBody fs = lam parseAll
+      | otherwise = lam . ctorE n $ map parseField fs
+
+    lam :: Exts.Exp () -> Exts.Exp ()
+    lam = Exts.lamE [Exts.pvar "s", Exts.pvar "h", Exts.pvar "x"]
+
+    parseField :: Field -> Exts.Exp ()
+    parseField x =
+      case fieldLocation x of
+        Just Headers -> parseHeadersE p x
+        Just Header -> parseHeadersE p x
+        Just StatusCode -> parseStatusE x
+        Just Body | body -> Exts.app pureE (var "x")
+        Nothing | body -> Exts.app pureE (var "x")
+        _ -> parseProto x
+
+    parseProto :: Field -> Exts.Exp ()
+    parseProto f =
+      case p of
+        _ | f ^. fieldPayload -> parseOne f
+        JSON -> parseJSONE p pJE pJEMay pJEDef f
+        RestJSON -> parseJSONE p pJE pJEMay pJEDef f
+        APIGateway -> parseJSONE p pJE pJEMay pJEDef f
+        _ -> parseXMLE p f
+
+    parseOne :: Field -> Exts.Exp ()
+    parseOne f
+      | fieldLit f =
+          if fieldIsParam f
+            then Exts.app (var "Prelude.pure") (var "x")
+            else -- Coerce is inserted here to handle newtypes such as Sensitive.
+
+              Exts.app (var "Prelude.pure")
+                . Exts.paren
+                . Exts.app justE
+                . Exts.paren
+                . Exts.app (var "Prelude.coerce")
+                $ var "x"
+      -- This ensures anything which is set as a payload,
+      -- but is a primitive type is just consumed as a bytestring.
+      | otherwise = parseAll
+
+    parseAll :: Exts.Exp ()
+    parseAll =
+      flip Exts.app (var "x") $
+        if any fieldLitPayload fs
+          then var "Prelude.pure"
+          else case p of
+            JSON -> var "Data.eitherParseJSON"
+            RestJSON -> var "Data.eitherParseJSON"
+            APIGateway -> var "Data.eitherParseJSON"
+            _ -> var "Data.parseXML"
+
+    body = any fieldStream fs
+
+-- FIXME: take method into account for responses, such as HEAD etc, particuarly
+-- when the body might be totally empty.
+responseF :: Protocol -> RefF a -> [Field] -> Exts.Exp ()
+responseF p r fs
+  | null fs = var "Response.receiveNull"
+  | any fieldStream fs = var "Response.receiveBody"
+  | any fieldLitPayload fs = var "Response.receiveBytes"
+  | Just x <- r ^. refResultWrapper = Exts.app (var (suf <> "Wrapper")) (str x)
+  | not $ any fieldBody fs = var "Response.receiveEmpty"
+  | otherwise = var suf
+  where
+    suf = "Response.receive" <> Proto.suffix p
+
+parseHeadersE :: Protocol -> Field -> Exts.Exp ()
+parseHeadersE p f
+  | TMap {} <- typeOf f = Exts.appFun pHMap [str n, h]
+  | fieldMaybe f = decodeE h pHMay n
+  | otherwise = decodeE h pH n
+  where
+    n = memberName p Output f
+    h = var "h"
+
+parseStatusE :: Field -> Exts.Exp ()
+parseStatusE f
+  | fieldMaybe f = Exts.app pureE (Exts.app justE v)
+  | otherwise = Exts.app pureE v
+  where
+    v = Exts.paren $ Exts.app (var "Prelude.fromEnum") (var "s")

From 29152fe315158b7d77942b10dda43c094bb97305 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Mon, 10 Nov 2025 07:57:15 +1000
Subject: [PATCH 07/41] gen(AWSRequest): be explicit that we consume `Metadata
 f`

---
 gen/src/Gen/AST/Data.hs                   | 2 +-
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index e0d0ef4117d..3ad66a28cdb 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -42,7 +42,7 @@ operationData cfg m o = do
 
   xis <- addInstances xa xs <$> requestInsts m (_opName o) h xr xs
 
-  cls <- pp Print $ AWSRequest.instanceD cfg m h (xr, xis) (yr, ys)
+  cls <- pp Print $ AWSRequest.instanceD cfg (m ^. metadata) h (xr, xis) (yr, ys)
   mpage <- pagerFields m o >>= traverse (pp Print . pagerD xn)
 
   yis' <- renderInsts p yn (responseInsts ys)
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 157209b9a02..326a8c74244 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -33,9 +33,8 @@ import Gen.Types
 import qualified Language.Haskell.Exts as Exts
 
 instanceD ::
-  (HasMetadata a Identity) =>
   Config ->
-  a ->
+  Metadata f ->
   HTTP ->
   (Ref, [Inst]) ->
   (Ref, [Field]) ->
@@ -54,9 +53,8 @@ assocD :: Id -> Text -> Text -> Exts.InstDecl ()
 assocD n x y = Exts.InsType () (tyapp (tycon x) (tycon (typeId n))) (tycon y)
 
 requestF ::
-  (HasMetadata a Identity) =>
   Config ->
-  a ->
+  Metadata f ->
   HTTP ->
   Ref ->
   [Inst] ->

From 77b8880f85f2f202d265417d6fdaa64bcae57771 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Mon, 10 Nov 2025 09:50:22 +1000
Subject: [PATCH 08/41] gen(Metadata): Use ApplicativeDo idiom for FromJSON
 instance

---
 gen/src/Gen/Types/Service.hs | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/gen/src/Gen/Types/Service.hs b/gen/src/Gen/Types/Service.hs
index 4b33c3d6a7c..7dfd215aea1 100644
--- a/gen/src/Gen/Types/Service.hs
+++ b/gen/src/Gen/Types/Service.hs
@@ -407,20 +407,20 @@ deriving instance Show (Metadata Identity)
 $(Lens.makeClassy ''Metadata)
 
 instance FromJSON (Metadata Maybe) where
-  parseJSON = Aeson.withObject "meta" $ \o ->
-    Metadata
-      <$> o .: "protocol"
-      <*> o .: "serviceAbbreviation"
-      <*> (o .: "serviceAbbreviation" <&> renameServiceFunction)
-      <*> (o .: "serviceFullName" <&> renameService)
-      <*> (o .: "signingName" <|> o .: "endpointPrefix")
-      <*> o .: "apiVersion"
-      <*> o .: "signatureVersion"
-      <*> o .: "endpointPrefix"
-      <*> o .:? "checksumFormat"
-      <*> o .:? "xmlNamespace"
-      <*> o .:? "jsonVersion"
-      <*> o .:? "targetPrefix"
+  parseJSON = Aeson.withObject "meta" $ \o -> do
+    _protocol <- o .: "protocol"
+    _serviceAbbrev <- o .: "serviceAbbreviation"
+    _serviceConfig <- o .: "serviceAbbreviation" <&> renameServiceFunction
+    _serviceFullName <- o .: "serviceFullName" <&> renameService
+    _signingName <- o .: "signingName" <|> o .: "endpointPrefix"
+    _apiVersion <- o .: "apiVersion"
+    _signatureVersion <- o .: "signatureVersion"
+    _endpointPrefix <- o .: "endpointPrefix"
+    _checksumFormat <- o .:? "checksumFormat"
+    _xmlNamespace <- o .:? "xmlNamespace"
+    _jsonVersion <- o .:? "jsonVersion"
+    _targetPrefix <- o .:? "targetPrefix"
+    pure Metadata {..}
 
 instance ToJSON (Metadata Identity) where
   toJSON = gToJSON' camel

From b1c27b63406f513aee5563f2b1ad34f9c4560a0e Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Tue, 11 Nov 2025 08:34:49 +1000
Subject: [PATCH 09/41] gen: Extract request function generation

---
 gen/src/Gen/AST/Data.hs                   | 34 +++++++++-
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 76 ++++++++---------------
 2 files changed, 58 insertions(+), 52 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 3ad66a28cdb..64f61e0543f 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -23,7 +23,7 @@ import Gen.AST.Data.Instance
 import Gen.AST.Data.Syntax as Syntax
 import qualified Gen.AST.Data.Syntax.AWSRequest as AWSRequest
 import Gen.Prelude
-import Gen.Types
+import Gen.Types hiding (method)
 import qualified Language.Haskell.Exts as Exts
 import Language.Haskell.Exts.Pretty (Pretty)
 
@@ -42,7 +42,37 @@ operationData cfg m o = do
 
   xis <- addInstances xa xs <$> requestInsts m (_opName o) h xr xs
 
-  cls <- pp Print $ AWSRequest.instanceD cfg (m ^. metadata) h (xr, xis) (yr, ys)
+  let requestFunction = method <> format
+        where
+          method = methodToText $ _method h
+          format =
+            case (mapMaybe fromInstance xis, _method h, m ^. protocol) of
+              (f : _, _, _) -> f
+              ([], POST, Query) -> "Query"
+              ([], POST, EC2) -> "Query"
+              _ -> ""
+          fromInstance = \case
+            ToBody {} -> Just "Body"
+            ToJSON {} -> Just "JSON"
+            ToElement {} -> Just "XML"
+            _ -> Nothing
+
+  cls <-
+    pp Print $
+      AWSRequest.instanceD
+        AWSRequest.Config
+          { -- Lookup a specific operationPlugins key before checking
+            -- for the wildcard.
+            operationPlugins =
+              fromMaybe [] $
+                (cfg ^. operationPlugins . Lens.at (identifier xr))
+                  <|> (cfg ^. operationPlugins . Lens.at (mkId "*")),
+            requestFunction,
+            serviceConfig = m ^. serviceConfig
+          }
+        (m ^. metadata)
+        xr
+        (yr, ys)
   mpage <- pagerFields m o >>= traverse (pp Print . pagerD xn)
 
   yis' <- renderInsts p yn (responseInsts ys)
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 326a8c74244..da2b0bc4940 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -2,9 +2,7 @@ module Gen.AST.Data.Syntax.AWSRequest where
 
 import qualified Control.Comonad as Comonad
 import qualified Control.Lens as Lens
-import qualified Data.HashMap.Strict as HashMap
 import Gen.AST.Data.Field (Field, fieldBody, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
-import Gen.AST.Data.Instance (Inst (..))
 import Gen.AST.Data.Syntax
   ( ctorE,
     decodeE,
@@ -29,73 +27,51 @@ import Gen.AST.Data.Syntax
   )
 import Gen.Prelude
 import qualified Gen.Protocol as Proto
-import Gen.Types
+import Gen.Types hiding (Config, operationPlugins, serviceConfig)
 import qualified Language.Haskell.Exts as Exts
 
+data Config = Config
+  { -- | List of function names to apply to computed request the
+    -- implementation of the @request@ function.
+    operationPlugins :: [Text],
+    -- | Name of the request function to call (@putBody@, @postQuery@, ...).
+    -- from the @"Request"@ module.
+    requestFunction :: Text,
+    -- | Name of the service config value to use by default. As of
+    -- 2025-11, always @"defaultService"@; the parser for 'Metadata'
+    -- would override the service abbrev in all cases.
+    serviceConfig :: Text
+  }
+
 instanceD ::
   Config ->
   Metadata f ->
-  HTTP ->
-  (Ref, [Inst]) ->
+  Ref ->
   (Ref, [Field]) ->
   Exts.Decl ()
-instanceD c m h (requestRef, requestInstances) (responseRef, responseFields) =
+instanceD c m requestRef (responseRef, responseFields) =
   instD
     "Core.AWSRequest"
     (identifier requestRef)
     $ Just
       [ assocD (identifier requestRef) "AWSResponse" (typeId (identifier responseRef)),
-        funArgsD "request" ["overrides"] (requestF c m h requestRef requestInstances),
+        funArgsD "request" ["overrides"] (requestF c),
         funD "response" (responseE (m ^. protocol) responseRef responseFields)
       ]
 
 assocD :: Id -> Text -> Text -> Exts.InstDecl ()
 assocD n x y = Exts.InsType () (tyapp (tycon x) (tycon (typeId n))) (tycon y)
 
-requestF ::
-  Config ->
-  Metadata f ->
-  HTTP ->
-  Ref ->
-  [Inst] ->
-  Exts.Exp ()
-requestF c meta h r is =
-  maybe e (foldr applyPlugin e) selectedPlugins
+requestF :: Config -> Exts.Exp ()
+requestF Config {..} = foldr applyPlugin e operationPlugins
   where
-    applyPlugin x =
-      -- Plugin functions are of the form :: Request a -> Request a
-      Exts.infixApp (var x) "Prelude.."
-
-    selectedPlugins =
-      -- Lookup a specific operationPlugins key before the wildcard.
-      HashMap.lookup (identifier r) (c ^. operationPlugins)
-        <|> HashMap.lookup (mkId "*") (c ^. operationPlugins)
-
-    e = Exts.app v (Exts.app (var "overrides") (var $ meta ^. serviceConfig))
-
-    v =
-      var
-        . mappend ("Request." <> methodToText m)
-        . fromMaybe mempty
-        . listToMaybe
-        $ mapMaybe f is
-
-    f = \case
-      ToBody {} -> Just "Body"
-      ToJSON {} -> Just "JSON"
-      ToElement {} -> Just "XML"
-      _
-        | p == Query,
-          m == POST ->
-            Just "Query"
-      _
-        | p == EC2,
-          m == POST ->
-            Just "Query"
-      _ -> Nothing
-
-    m = h ^. method
-    p = meta ^. protocol
+    -- Plugin functions are of the form :: Request a -> Request a
+    applyPlugin x = Exts.infixApp (var x) "Prelude.."
+
+    e =
+      Exts.app
+        (var $ "Request." <> requestFunction)
+        (Exts.app (var "overrides") (var serviceConfig))
 
 responseE :: Protocol -> Ref -> [Field] -> Exts.Exp ()
 responseE p r fs = Exts.app (responseF p r fs) bdy

From 43f7bc64b9c82e1e3170d9e42883022242ad410b Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Tue, 11 Nov 2025 08:44:17 +1000
Subject: [PATCH 10/41] gen (AWSRequest): Push all of the request declaration
 into requestF

---
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index da2b0bc4940..40a48d02353 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -55,15 +55,16 @@ instanceD c m requestRef (responseRef, responseFields) =
     (identifier requestRef)
     $ Just
       [ assocD (identifier requestRef) "AWSResponse" (typeId (identifier responseRef)),
-        funArgsD "request" ["overrides"] (requestF c),
+        requestD c,
         funD "response" (responseE (m ^. protocol) responseRef responseFields)
       ]
 
 assocD :: Id -> Text -> Text -> Exts.InstDecl ()
 assocD n x y = Exts.InsType () (tyapp (tycon x) (tycon (typeId n))) (tycon y)
 
-requestF :: Config -> Exts.Exp ()
-requestF Config {..} = foldr applyPlugin e operationPlugins
+requestD :: Config -> Exts.InstDecl ()
+requestD Config {..} =
+  funArgsD "request" ["overrides"] $ foldr applyPlugin e operationPlugins
   where
     -- Plugin functions are of the form :: Request a -> Request a
     applyPlugin x = Exts.infixApp (var x) "Prelude.."

From 32b70dda6ce6020ee7acb9f271358e792d40a5af Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Wed, 12 Nov 2025 07:37:09 +1000
Subject: [PATCH 11/41] gen(AWSRequest): Start converting to depend on
 responseType (Id)

---
 gen/src/Gen/AST/Data.hs                   |  7 ++---
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 31 ++++++++++++++---------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 64f61e0543f..3eb05d1dcdc 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -61,17 +61,18 @@ operationData cfg m o = do
     pp Print $
       AWSRequest.instanceD
         AWSRequest.Config
-          { -- Lookup a specific operationPlugins key before checking
+          { requestType = identifier xr,
+            requestFunction,
+            responseType = identifier yr,
+            -- Lookup a specific operationPlugins key before checking
             -- for the wildcard.
             operationPlugins =
               fromMaybe [] $
                 (cfg ^. operationPlugins . Lens.at (identifier xr))
                   <|> (cfg ^. operationPlugins . Lens.at (mkId "*")),
-            requestFunction,
             serviceConfig = m ^. serviceConfig
           }
         (m ^. metadata)
-        xr
         (yr, ys)
   mpage <- pagerFields m o >>= traverse (pp Print . pagerD xn)
 
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 40a48d02353..d6919fc0a20 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -31,12 +31,18 @@ import Gen.Types hiding (Config, operationPlugins, serviceConfig)
 import qualified Language.Haskell.Exts as Exts
 
 data Config = Config
-  { -- | List of function names to apply to computed request the
-    -- implementation of the @request@ function.
-    operationPlugins :: [Text],
+  { -- | Name of the data type we generate to represent the input
+    -- shape from botocore.
+    requestType :: Id,
     -- | Name of the request function to call (@putBody@, @postQuery@, ...).
     -- from the @"Request"@ module.
     requestFunction :: Text,
+    -- | List of function names to apply to the computed request in
+    -- the implementation of the @request@ function.
+    operationPlugins :: [Text],
+    -- | Name of the data type we generate for the botocore output
+    -- shape that corresponds to 'requestType'.
+    responseType :: Id,
     -- | Name of the service config value to use by default. As of
     -- 2025-11, always @"defaultService"@; the parser for 'Metadata'
     -- would override the service abbrev in all cases.
@@ -46,21 +52,22 @@ data Config = Config
 instanceD ::
   Config ->
   Metadata f ->
-  Ref ->
   (Ref, [Field]) ->
   Exts.Decl ()
-instanceD c m requestRef (responseRef, responseFields) =
-  instD
-    "Core.AWSRequest"
-    (identifier requestRef)
-    $ Just
-      [ assocD (identifier requestRef) "AWSResponse" (typeId (identifier responseRef)),
+instanceD c@Config {requestType} m (responseRef, responseFields) =
+  instD "Core.AWSRequest" requestType $
+    Just
+      [ awsResponseD c,
         requestD c,
         funD "response" (responseE (m ^. protocol) responseRef responseFields)
       ]
 
-assocD :: Id -> Text -> Text -> Exts.InstDecl ()
-assocD n x y = Exts.InsType () (tyapp (tycon x) (tycon (typeId n))) (tycon y)
+awsResponseD :: Config -> Exts.InstDecl ()
+awsResponseD Config {..} =
+  Exts.InsType
+    ()
+    (tycon "AWSResponse" `tyapp` tycon (typeId requestType))
+    (tycon (typeId responseType))
 
 requestD :: Config -> Exts.InstDecl ()
 requestD Config {..} =

From 9707eb0b2a01d4250078a8cf8d5207f4e46af827 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 30 Jan 2026 21:06:49 +1000
Subject: [PATCH 12/41] gen(AWSRequest): Unpick some more of the logic

---
 gen/src/Gen/AST/Data.hs                   | 22 +++++++-
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 69 +++++++++++++++--------
 2 files changed, 65 insertions(+), 26 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 3eb05d1dcdc..74719ca89f8 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -8,6 +8,7 @@ module Gen.AST.Data
   )
 where
 
+import Control.Comonad (extract)
 import qualified Control.Lens as Lens
 import qualified Control.Monad.Trans.State as State
 import qualified Data.ByteString.Char8 as ByteString.Char8
@@ -57,19 +58,34 @@ operationData cfg m o = do
             ToElement {} -> Just "XML"
             _ -> Nothing
 
+      responseParser
+        | null ys = AWSRequest.ParseNull
+        | isShared . extract $ yr ^. refAnn,
+          all fieldBody ys =
+            let wrapper = yr ^. refResultWrapper
+             in case m ^. protocol of
+                  APIGateway -> AWSRequest.ParseAllJSON
+                  JSON -> AWSRequest.ParseAllJSON
+                  RestJSON -> AWSRequest.ParseAllJSON
+                  EC2 -> AWSRequest.ParseAllXML wrapper
+                  Query -> AWSRequest.ParseAllXML wrapper
+                  RestXML -> AWSRequest.ParseAllXML wrapper
+        | otherwise = AWSRequest.FigureItOut
+
   cls <-
     pp Print $
       AWSRequest.instanceD
         AWSRequest.Config
           { requestType = identifier xr,
-            requestFunction,
-            responseType = identifier yr,
             -- Lookup a specific operationPlugins key before checking
             -- for the wildcard.
-            operationPlugins =
+            requestOperationPlugins =
               fromMaybe [] $
                 (cfg ^. operationPlugins . Lens.at (identifier xr))
                   <|> (cfg ^. operationPlugins . Lens.at (mkId "*")),
+            requestFunction,
+            responseType = identifier yr,
+            responseParser,
             serviceConfig = m ^. serviceConfig
           }
         (m ^. metadata)
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index d6919fc0a20..28918139227 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -27,7 +27,7 @@ import Gen.AST.Data.Syntax
   )
 import Gen.Prelude
 import qualified Gen.Protocol as Proto
-import Gen.Types hiding (Config, operationPlugins, serviceConfig)
+import Gen.Types hiding (Config, serviceConfig)
 import qualified Language.Haskell.Exts as Exts
 
 data Config = Config
@@ -39,15 +39,30 @@ data Config = Config
     requestFunction :: Text,
     -- | List of function names to apply to the computed request in
     -- the implementation of the @request@ function.
-    operationPlugins :: [Text],
+    requestOperationPlugins :: [Text],
     -- | Name of the data type we generate for the botocore output
     -- shape that corresponds to 'requestType'.
     responseType :: Id,
+    -- | How to parse the response from AWS.
+    responseParser :: ResponseParser,
     -- | Name of the service config value to use by default. As of
     -- 2025-11, always @"defaultService"@; the parser for 'Metadata'
     -- would override the service abbrev in all cases.
     serviceConfig :: Text
   }
+  deriving (Show)
+
+-- | How to generate the parser for AWS's response to an API call.
+data ResponseParser
+  = -- | Perform no parsing and return an empty response. The response
+    -- constructor in 'responseType' must take no arguments.
+    ParseNull
+  | -- | Parse the entire response as JSON.
+    ParseAllJSON
+  | -- | Parse the entire resposne as XML, with an optional wrapper.
+    ParseAllXML (Maybe Text)
+  | FigureItOut
+  deriving (Show)
 
 instanceD ::
   Config ->
@@ -59,7 +74,7 @@ instanceD c@Config {requestType} m (responseRef, responseFields) =
     Just
       [ awsResponseD c,
         requestD c,
-        funD "response" (responseE (m ^. protocol) responseRef responseFields)
+        funD "response" (responseE c (m ^. protocol) responseRef responseFields)
       ]
 
 awsResponseD :: Config -> Exts.InstDecl ()
@@ -71,7 +86,7 @@ awsResponseD Config {..} =
 
 requestD :: Config -> Exts.InstDecl ()
 requestD Config {..} =
-  funArgsD "request" ["overrides"] $ foldr applyPlugin e operationPlugins
+  funArgsD "request" ["overrides"] $ foldr applyPlugin e requestOperationPlugins
   where
     -- Plugin functions are of the form :: Request a -> Request a
     applyPlugin x = Exts.infixApp (var x) "Prelude.."
@@ -81,17 +96,26 @@ requestD Config {..} =
         (var $ "Request." <> requestFunction)
         (Exts.app (var "overrides") (var serviceConfig))
 
-responseE :: Protocol -> Ref -> [Field] -> Exts.Exp ()
-responseE p r fs = Exts.app (responseF p r fs) bdy
+responseE :: Config -> Protocol -> Ref -> [Field] -> Exts.Exp ()
+responseE Config {..} p r fs =
+  case responseParser of
+    ParseNull -> var "Response.receiveNull" `Exts.app` var (ctorId responseType)
+    ParseAllJSON ->
+      var "Response.receiveJSON"
+        `Exts.app` lam (var "Data.eitherParseJSON" `Exts.app` var "x")
+    ParseAllXML Nothing ->
+      var "Response.receiveXML"
+        `Exts.app` lam (var "Data.parseXML" `Exts.app` var "x")
+    ParseAllXML (Just wrapper) ->
+      var "Response.receiveXMLWrapper"
+        `Exts.app` str wrapper
+        `Exts.app` lam (var "Data.parseXML" `Exts.app` var "x")
+    FigureItOut -> Exts.app responseF bdy
   where
     n = r ^. Lens.to identifier
-    s = r ^. refAnn . Lens.to Comonad.extract
 
     bdy :: Exts.Exp ()
-    bdy
-      | null fs = var (ctorId n)
-      | isShared s, all fieldBody fs = lam parseAll
-      | otherwise = lam . ctorE n $ map parseField fs
+    bdy = lam . ctorE n $ map parseField fs
 
     lam :: Exts.Exp () -> Exts.Exp ()
     lam = Exts.lamE [Exts.pvar "s", Exts.pvar "h", Exts.pvar "x"]
@@ -145,18 +169,17 @@ responseE p r fs = Exts.app (responseF p r fs) bdy
 
     body = any fieldStream fs
 
--- FIXME: take method into account for responses, such as HEAD etc, particuarly
--- when the body might be totally empty.
-responseF :: Protocol -> RefF a -> [Field] -> Exts.Exp ()
-responseF p r fs
-  | null fs = var "Response.receiveNull"
-  | any fieldStream fs = var "Response.receiveBody"
-  | any fieldLitPayload fs = var "Response.receiveBytes"
-  | Just x <- r ^. refResultWrapper = Exts.app (var (suf <> "Wrapper")) (str x)
-  | not $ any fieldBody fs = var "Response.receiveEmpty"
-  | otherwise = var suf
-  where
-    suf = "Response.receive" <> Proto.suffix p
+    -- FIXME: take method into account for responses, such as HEAD
+    -- etc, particuarly when the body might be totally empty.
+    responseF :: Exts.Exp ()
+    responseF
+      | any fieldStream fs = var "Response.receiveBody"
+      | any fieldLitPayload fs = var "Response.receiveBytes"
+      | Just x <- r ^. refResultWrapper = Exts.app (var (suf <> "Wrapper")) (str x)
+      | not $ any fieldBody fs = var "Response.receiveEmpty"
+      | otherwise = var suf
+      where
+        suf = "Response.receive" <> Proto.suffix p
 
 parseHeadersE :: Protocol -> Field -> Exts.Exp ()
 parseHeadersE p f

From 38e1133a460f967791378959fb83484df715a480 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sat, 14 Mar 2026 23:36:31 +0000
Subject: [PATCH 13/41] gen: Small tidyups

---
 gen/amazonka-gen.cabal                    | 2 +-
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 6 +-----
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/gen/amazonka-gen.cabal b/gen/amazonka-gen.cabal
index 2d73e2d30f2..3c91421ee6e 100644
--- a/gen/amazonka-gen.cabal
+++ b/gen/amazonka-gen.cabal
@@ -125,13 +125,13 @@ library
     Gen.Types.URI
     Gen.Types.Waiter
     Gen.WordFrequency
-    Paths_amazonka_gen
 
 executable gen
   import:         base
   hs-source-dirs: bin
   main-is:        gen.hs
   ghc-options:    -threaded -rtsopts "-with-rtsopts=-A128m -I0 -qg0"
+  other-modules:  Paths_amazonka_gen
   build-depends:
     , amazonka-gen
     , filepath
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 28918139227..adc50063c93 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -1,7 +1,5 @@
 module Gen.AST.Data.Syntax.AWSRequest where
 
-import qualified Control.Comonad as Comonad
-import qualified Control.Lens as Lens
 import Gen.AST.Data.Field (Field, fieldBody, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
 import Gen.AST.Data.Syntax
   ( ctorE,
@@ -112,10 +110,8 @@ responseE Config {..} p r fs =
         `Exts.app` lam (var "Data.parseXML" `Exts.app` var "x")
     FigureItOut -> Exts.app responseF bdy
   where
-    n = r ^. Lens.to identifier
-
     bdy :: Exts.Exp ()
-    bdy = lam . ctorE n $ map parseField fs
+    bdy = lam . ctorE (identifier r) $ map parseField fs
 
     lam :: Exts.Exp () -> Exts.Exp ()
     lam = Exts.lamE [Exts.pvar "s", Exts.pvar "h", Exts.pvar "x"]

From 65105284e712312024c9b96b79c8c3d3f12ff59b Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sat, 14 Mar 2026 23:53:04 +0000
Subject: [PATCH 14/41] amazonka-core/gen: Rename `receiveBody` ->
 `receiveStreamingBody`

---
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs  |  2 +-
 lib/amazonka-core/src/Amazonka/Response.hs | 44 ++++++++++++++--------
 lib/amazonka/CHANGELOG.md                  |  3 +-
 3 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index adc50063c93..6aa0b73bd9c 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -169,7 +169,7 @@ responseE Config {..} p r fs =
     -- etc, particuarly when the body might be totally empty.
     responseF :: Exts.Exp ()
     responseF
-      | any fieldStream fs = var "Response.receiveBody"
+      | any fieldStream fs = var "Response.receiveStreamingBody"
       | any fieldLitPayload fs = var "Response.receiveBytes"
       | Just x <- r ^. refResultWrapper = Exts.app (var (suf <> "Wrapper")) (str x)
       | not $ any fieldBody fs = var "Response.receiveEmpty"
diff --git a/lib/amazonka-core/src/Amazonka/Response.hs b/lib/amazonka-core/src/Amazonka/Response.hs
index 442db1a7dff..eec55875c6f 100644
--- a/lib/amazonka-core/src/Amazonka/Response.hs
+++ b/lib/amazonka-core/src/Amazonka/Response.hs
@@ -10,10 +10,11 @@
 -- the connection. This is needed to avoid hitting this issue:
 -- <https://github.com/brendanhay/amazonka/issues/490>.
 --
--- The only exception is 'receiveBody', which passes a streaming response
--- body to a callback and thus is not allowed to close the connection. Users
--- of streaming functions are advised to be careful and consume the response
--- body manually if they want the connection to be closed promptly.
+-- The only exception is 'receiveStreamingBody', which passes a streaming
+-- response body to a callback and thus is not allowed to close the
+-- connection. Users of streaming functions are advised to be careful and
+-- consume the response body manually if they want the connection to be closed
+-- promptly.
 --
 -- Note that using 'runResourceT' will always close the connection.
 module Amazonka.Response
@@ -24,6 +25,7 @@ module Amazonka.Response
     receiveJSON,
     receiveBytes,
     receiveBody,
+    receiveStreamingBody,
   )
 where
 
@@ -43,7 +45,7 @@ import Network.HTTP.Types (ResponseHeaders)
 import qualified Text.XML as XML
 
 receiveNull ::
-  MonadResource m =>
+  (MonadResource m) =>
   AWSResponse a ->
   (ByteStringLazy -> IO ByteStringLazy) ->
   Service ->
@@ -55,7 +57,7 @@ receiveNull rs _ =
     liftIO (Client.responseClose r) $> Right rs
 
 receiveEmpty ::
-  MonadResource m =>
+  (MonadResource m) =>
   (Int -> ResponseHeaders -> () -> Either String (AWSResponse a)) ->
   (ByteStringLazy -> IO ByteStringLazy) ->
   Service ->
@@ -67,7 +69,7 @@ receiveEmpty f _ =
     liftIO (Client.responseClose r) $> f s h ()
 
 receiveXMLWrapper ::
-  MonadResource m =>
+  (MonadResource m) =>
   Text ->
   (Int -> ResponseHeaders -> [XML.Node] -> Either String (AWSResponse a)) ->
   (ByteStringLazy -> IO ByteStringLazy) ->
@@ -78,7 +80,7 @@ receiveXMLWrapper ::
 receiveXMLWrapper n f = receiveXML (\s h x -> x .@ n >>= f s h)
 
 receiveXML ::
-  MonadResource m =>
+  (MonadResource m) =>
   (Int -> ResponseHeaders -> [XML.Node] -> Either String (AWSResponse a)) ->
   (ByteStringLazy -> IO ByteStringLazy) ->
   Service ->
@@ -88,7 +90,7 @@ receiveXML ::
 receiveXML = deserialise decodeXML
 
 receiveJSON ::
-  MonadResource m =>
+  (MonadResource m) =>
   (Int -> ResponseHeaders -> Aeson.Object -> Either String (AWSResponse a)) ->
   (ByteStringLazy -> IO ByteStringLazy) ->
   Service ->
@@ -98,7 +100,7 @@ receiveJSON ::
 receiveJSON = deserialise Aeson.eitherDecode'
 
 receiveBytes ::
-  MonadResource m =>
+  (MonadResource m) =>
   (Int -> ResponseHeaders -> ByteString -> Either String (AWSResponse a)) ->
   (ByteStringLazy -> IO ByteStringLazy) ->
   Service ->
@@ -107,21 +109,33 @@ receiveBytes ::
   m (Either Error (ClientResponse (AWSResponse a)))
 receiveBytes = deserialise (Right . LBS.toStrict)
 
+-- | Deprecated alias for 'receiveStreamingBody'.
 receiveBody ::
-  MonadResource m =>
+  (MonadResource m) =>
   (Int -> ResponseHeaders -> ResponseBody -> Either String (AWSResponse a)) ->
   (ByteStringLazy -> IO ByteStringLazy) ->
   Service ->
   Proxy a ->
   ClientResponse ClientBody ->
   m (Either Error (ClientResponse (AWSResponse a)))
-receiveBody f _ =
+receiveBody = receiveStreamingBody
+{-# DEPRECATED receiveBody "this function will be removed in Amazonka 2.2" #-}
+
+receiveStreamingBody ::
+  (MonadResource m) =>
+  (Int -> ResponseHeaders -> ResponseBody -> Either String (AWSResponse a)) ->
+  (ByteStringLazy -> IO ByteStringLazy) ->
+  Service ->
+  Proxy a ->
+  ClientResponse ClientBody ->
+  m (Either Error (ClientResponse (AWSResponse a)))
+receiveStreamingBody f _ =
   stream $ \_ s h x ->
     pure (f s h (ResponseBody x))
 
 -- | Deserialise an entire response body, such as an XML or JSON payload.
 deserialise ::
-  MonadResource m =>
+  (MonadResource m) =>
   (ByteStringLazy -> Either String b) ->
   (Int -> ResponseHeaders -> b -> Either String (AWSResponse a)) ->
   (ByteStringLazy -> IO ByteStringLazy) ->
@@ -146,7 +160,7 @@ deserialise reader parser responseBodyHook Service {..} _ rs =
 
 -- | Stream a raw response body, such as an S3 object payload.
 stream ::
-  MonadResource m =>
+  (MonadResource m) =>
   ( ClientResponse () ->
     Int ->
     ResponseHeaders ->
@@ -173,5 +187,5 @@ stream parser Service {..} _ rs =
         Except.throwE $
           SerializeError (SerializeError' abbrev status Nothing err)
 
-sinkLBS :: MonadResource m => ClientBody -> m ByteStringLazy
+sinkLBS :: (MonadResource m) => ClientBody -> m ByteStringLazy
 sinkLBS bdy = liftResourceT (bdy `Conduit.connect` Conduit.Binary.sinkLbs)
diff --git a/lib/amazonka/CHANGELOG.md b/lib/amazonka/CHANGELOG.md
index c328efc7045..d7ab040e716 100644
--- a/lib/amazonka/CHANGELOG.md
+++ b/lib/amazonka/CHANGELOG.md
@@ -122,7 +122,8 @@
 [\#955](https://github.com/brendanhay/amazonka/pull/955)
 - `amazonka-core`: Support Cloudflare R2 by adjusting which headers get signed
 [\#977](https://github.com/brendanhay/amazonka/pull/977)
-
+- `amazonka-core`: `Amazonka.Response.receiveBody` has been renamed to `Amazonka.Response.receiveStreamingBody`. This is an internal function used in service bindings and should not affect normal users. `Amazonka.Response.receiveBody` will remain as a deprecated alias until Amazonka 2.2.
+[\#???](https://github.com/brendanhay/amazonka/pull/???)
 
 ## [2.0.0](https://github.com/brendanhay/amazonka/tree/2.0.0)
 Released: **28 July 2023**, Compare: [2.0.0-rc2](https://github.com/brendanhay/amazonka/compare/2.0.0-rc2...2.0.0)

From 82de6c51a34196941f9ca2229f6a74aa2c3047db Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:08 +0000
Subject: [PATCH 15/41] amazonka-backupstorage: regenerating service

---
 .../gen/Amazonka/BackupStorage/GetChunk.hs                      | 2 +-
 .../gen/Amazonka/BackupStorage/GetObjectMetadata.hs             | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetChunk.hs b/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetChunk.hs
index f502be11f54..25420c204ce 100644
--- a/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetChunk.hs
+++ b/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetChunk.hs
@@ -96,7 +96,7 @@ instance Core.AWSRequest GetChunk where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetChunkResponse'
             Prelude.<$> (Prelude.pure (Prelude.fromEnum s))
diff --git a/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetObjectMetadata.hs b/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetObjectMetadata.hs
index 81763f91650..dc208250fbc 100644
--- a/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetObjectMetadata.hs
+++ b/lib/services/amazonka-backupstorage/gen/Amazonka/BackupStorage/GetObjectMetadata.hs
@@ -99,7 +99,7 @@ instance Core.AWSRequest GetObjectMetadata where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetObjectMetadataResponse'
             Prelude.<$> (h Data..#? "x-amz-checksum")

From 9d496e7d022c1a00f1587f05025587aa0b72b32e Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:12 +0000
Subject: [PATCH 16/41] amazonka-codeartifact: regenerating service

---
 .../gen/Amazonka/CodeArtifact/GetPackageVersionAsset.hs         | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-codeartifact/gen/Amazonka/CodeArtifact/GetPackageVersionAsset.hs b/lib/services/amazonka-codeartifact/gen/Amazonka/CodeArtifact/GetPackageVersionAsset.hs
index ea3e50f4d85..238c8d80aeb 100644
--- a/lib/services/amazonka-codeartifact/gen/Amazonka/CodeArtifact/GetPackageVersionAsset.hs
+++ b/lib/services/amazonka-codeartifact/gen/Amazonka/CodeArtifact/GetPackageVersionAsset.hs
@@ -230,7 +230,7 @@ instance Core.AWSRequest GetPackageVersionAsset where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetPackageVersionAssetResponse'
             Prelude.<$> (h Data..#? "X-AssetName")

From 3d3d8a3d3e7958e708615adf729eb7c41e58a524 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:18 +0000
Subject: [PATCH 17/41] amazonka-ebs: regenerating service

---
 lib/services/amazonka-ebs/gen/Amazonka/EBS/GetSnapshotBlock.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-ebs/gen/Amazonka/EBS/GetSnapshotBlock.hs b/lib/services/amazonka-ebs/gen/Amazonka/EBS/GetSnapshotBlock.hs
index 3bda84a6af5..e77ad0d8d93 100644
--- a/lib/services/amazonka-ebs/gen/Amazonka/EBS/GetSnapshotBlock.hs
+++ b/lib/services/amazonka-ebs/gen/Amazonka/EBS/GetSnapshotBlock.hs
@@ -149,7 +149,7 @@ instance Core.AWSRequest GetSnapshotBlock where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetSnapshotBlockResponse'
             Prelude.<$> (h Data..#? "x-amz-Checksum")

From 2ad86cd0a360e3dd32c5c1d75573b14890e5fdf6 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:23 +0000
Subject: [PATCH 18/41] amazonka-glacier: regenerating service

---
 .../amazonka-glacier/gen/Amazonka/Glacier/GetJobOutput.hs       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-glacier/gen/Amazonka/Glacier/GetJobOutput.hs b/lib/services/amazonka-glacier/gen/Amazonka/Glacier/GetJobOutput.hs
index ad091371bf9..e686f3889f4 100644
--- a/lib/services/amazonka-glacier/gen/Amazonka/Glacier/GetJobOutput.hs
+++ b/lib/services/amazonka-glacier/gen/Amazonka/Glacier/GetJobOutput.hs
@@ -271,7 +271,7 @@ instance Core.AWSRequest GetJobOutput where
     Request.glacierVersionHeader (Core.version defaultService)
       Prelude.. Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetJobOutputResponse'
             Prelude.<$> (h Data..#? "Accept-Ranges")

From 744b0b592046c479c26189c8670716dc62b5ff76 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:29 +0000
Subject: [PATCH 19/41] amazonka-kinesis-video-archived-media: regenerating
 service

---
 .../gen/Amazonka/KinesisVideoArchivedMedia/GetClip.hs           | 2 +-
 .../KinesisVideoArchivedMedia/GetMediaForFragmentList.hs        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetClip.hs b/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetClip.hs
index 6b9d924f421..e9a11f735f5 100644
--- a/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetClip.hs
+++ b/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetClip.hs
@@ -159,7 +159,7 @@ instance Core.AWSRequest GetClip where
   request overrides =
     Request.postJSON (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetClipResponse'
             Prelude.<$> (h Data..#? "Content-Type")
diff --git a/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetMediaForFragmentList.hs b/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetMediaForFragmentList.hs
index 48d493b668b..e399361ade5 100644
--- a/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetMediaForFragmentList.hs
+++ b/lib/services/amazonka-kinesis-video-archived-media/gen/Amazonka/KinesisVideoArchivedMedia/GetMediaForFragmentList.hs
@@ -146,7 +146,7 @@ instance Core.AWSRequest GetMediaForFragmentList where
   request overrides =
     Request.postJSON (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetMediaForFragmentListResponse'
             Prelude.<$> (h Data..#? "Content-Type")

From aa4158344fe937356176ba172b4a6ab1eefc7086 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:29 +0000
Subject: [PATCH 20/41] amazonka-kinesis-video-media: regenerating service

---
 .../gen/Amazonka/KinesisVideoMedia/GetMedia.hs                  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-kinesis-video-media/gen/Amazonka/KinesisVideoMedia/GetMedia.hs b/lib/services/amazonka-kinesis-video-media/gen/Amazonka/KinesisVideoMedia/GetMedia.hs
index 3df189de94b..3b01f71d818 100644
--- a/lib/services/amazonka-kinesis-video-media/gen/Amazonka/KinesisVideoMedia/GetMedia.hs
+++ b/lib/services/amazonka-kinesis-video-media/gen/Amazonka/KinesisVideoMedia/GetMedia.hs
@@ -154,7 +154,7 @@ instance Core.AWSRequest GetMedia where
   request overrides =
     Request.postJSON (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetMediaResponse'
             Prelude.<$> (h Data..#? "Content-Type")

From 13e56558ca32c639a76a510009ace606dbc55dea Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:30 +0000
Subject: [PATCH 21/41] amazonka-lakeformation: regenerating service

---
 .../gen/Amazonka/LakeFormation/GetWorkUnitResults.hs            | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-lakeformation/gen/Amazonka/LakeFormation/GetWorkUnitResults.hs b/lib/services/amazonka-lakeformation/gen/Amazonka/LakeFormation/GetWorkUnitResults.hs
index ca2c6da7031..f2718d5f423 100644
--- a/lib/services/amazonka-lakeformation/gen/Amazonka/LakeFormation/GetWorkUnitResults.hs
+++ b/lib/services/amazonka-lakeformation/gen/Amazonka/LakeFormation/GetWorkUnitResults.hs
@@ -121,7 +121,7 @@ instance Core.AWSRequest GetWorkUnitResults where
   request overrides =
     Request.postJSON (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetWorkUnitResultsResponse'
             Prelude.<$> (Prelude.pure (Prelude.fromEnum s))

From 538d36572ea72a72a78d77c1f81ec1ca88c1380e Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:30 +0000
Subject: [PATCH 22/41] amazonka-lex-runtime: regenerating service

---
 .../amazonka-lex-runtime/gen/Amazonka/LexRuntime/PostContent.hs | 2 +-
 .../amazonka-lex-runtime/gen/Amazonka/LexRuntime/PutSession.hs  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PostContent.hs b/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PostContent.hs
index 80edcb506a8..74429b506e3 100644
--- a/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PostContent.hs
+++ b/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PostContent.hs
@@ -553,7 +553,7 @@ instance Core.AWSRequest PostContent where
   request overrides =
     Request.postBody (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           PostContentResponse'
             Prelude.<$> (h Data..#? "x-amz-lex-active-contexts")
diff --git a/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PutSession.hs b/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PutSession.hs
index 0904a178b8f..613b8c1f6db 100644
--- a/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PutSession.hs
+++ b/lib/services/amazonka-lex-runtime/gen/Amazonka/LexRuntime/PutSession.hs
@@ -333,7 +333,7 @@ instance Core.AWSRequest PutSession where
   request overrides =
     Request.postJSON (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           PutSessionResponse'
             Prelude.<$> (h Data..#? "x-amz-lex-active-contexts")

From 5aefa1dfe4fb356136beaaa44dbcf0d3d28efaa6 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:34 +0000
Subject: [PATCH 23/41] amazonka-medialive: regenerating service

---
 .../gen/Amazonka/MediaLive/DescribeInputDeviceThumbnail.hs      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-medialive/gen/Amazonka/MediaLive/DescribeInputDeviceThumbnail.hs b/lib/services/amazonka-medialive/gen/Amazonka/MediaLive/DescribeInputDeviceThumbnail.hs
index c479891f1d5..061fbd2ea85 100644
--- a/lib/services/amazonka-medialive/gen/Amazonka/MediaLive/DescribeInputDeviceThumbnail.hs
+++ b/lib/services/amazonka-medialive/gen/Amazonka/MediaLive/DescribeInputDeviceThumbnail.hs
@@ -104,7 +104,7 @@ instance Core.AWSRequest DescribeInputDeviceThumbnail where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           DescribeInputDeviceThumbnailResponse'
             Prelude.<$> (h Data..#? "Content-Length")

From fca88047a33fb09771045dcc0f856e34b19210bd Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:34 +0000
Subject: [PATCH 24/41] amazonka-mediastore-dataplane: regenerating service

---
 .../gen/Amazonka/MediaStoreData/GetObject.hs                    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-mediastore-dataplane/gen/Amazonka/MediaStoreData/GetObject.hs b/lib/services/amazonka-mediastore-dataplane/gen/Amazonka/MediaStoreData/GetObject.hs
index 956d0656049..8e65c35cb66 100644
--- a/lib/services/amazonka-mediastore-dataplane/gen/Amazonka/MediaStoreData/GetObject.hs
+++ b/lib/services/amazonka-mediastore-dataplane/gen/Amazonka/MediaStoreData/GetObject.hs
@@ -183,7 +183,7 @@ instance Core.AWSRequest GetObject where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetObjectResponse'
             Prelude.<$> (h Data..#? "Cache-Control")

From 7f54b48cc93d4e619df1f092aa6c78c0f1b5ec26 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:37 +0000
Subject: [PATCH 25/41] amazonka-omics: regenerating service

---
 lib/services/amazonka-omics/gen/Amazonka/Omics/GetReadSet.hs   | 2 +-
 lib/services/amazonka-omics/gen/Amazonka/Omics/GetReference.hs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReadSet.hs b/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReadSet.hs
index 810c507a495..1452a969b45 100644
--- a/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReadSet.hs
+++ b/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReadSet.hs
@@ -115,7 +115,7 @@ instance Core.AWSRequest GetReadSet where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetReadSetResponse'
             Prelude.<$> (Prelude.pure (Prelude.fromEnum s))
diff --git a/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReference.hs b/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReference.hs
index fd2d64fd27b..707906bdec4 100644
--- a/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReference.hs
+++ b/lib/services/amazonka-omics/gen/Amazonka/Omics/GetReference.hs
@@ -125,7 +125,7 @@ instance Core.AWSRequest GetReference where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetReferenceResponse'
             Prelude.<$> (Prelude.pure (Prelude.fromEnum s))

From f021ebf85dfa31cdf9da96279863b3ef330e7c80 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:39 +0000
Subject: [PATCH 26/41] amazonka-polly: regenerating service

---
 .../amazonka-polly/gen/Amazonka/Polly/SynthesizeSpeech.hs       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-polly/gen/Amazonka/Polly/SynthesizeSpeech.hs b/lib/services/amazonka-polly/gen/Amazonka/Polly/SynthesizeSpeech.hs
index 04fd2fd6dba..6c5e0831cc1 100644
--- a/lib/services/amazonka-polly/gen/Amazonka/Polly/SynthesizeSpeech.hs
+++ b/lib/services/amazonka-polly/gen/Amazonka/Polly/SynthesizeSpeech.hs
@@ -333,7 +333,7 @@ instance Core.AWSRequest SynthesizeSpeech where
   request overrides =
     Request.postJSON (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           SynthesizeSpeechResponse'
             Prelude.<$> (h Data..#? "Content-Type")

From d9144af409e4564fd4c427b4347be66c14f5fcda Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:44 +0000
Subject: [PATCH 27/41] amazonka-s3: regenerating service

---
 lib/services/amazonka-s3/gen/Amazonka/S3/GetObject.hs        | 2 +-
 lib/services/amazonka-s3/gen/Amazonka/S3/GetObjectTorrent.hs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/services/amazonka-s3/gen/Amazonka/S3/GetObject.hs b/lib/services/amazonka-s3/gen/Amazonka/S3/GetObject.hs
index 1cef8bc552d..50efcfdc12c 100644
--- a/lib/services/amazonka-s3/gen/Amazonka/S3/GetObject.hs
+++ b/lib/services/amazonka-s3/gen/Amazonka/S3/GetObject.hs
@@ -585,7 +585,7 @@ instance Core.AWSRequest GetObject where
     Request.s3vhost
       Prelude.. Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetObjectResponse'
             Prelude.<$> (h Data..#? "accept-ranges")
diff --git a/lib/services/amazonka-s3/gen/Amazonka/S3/GetObjectTorrent.hs b/lib/services/amazonka-s3/gen/Amazonka/S3/GetObjectTorrent.hs
index c1227f44cfc..68a36abd064 100644
--- a/lib/services/amazonka-s3/gen/Amazonka/S3/GetObjectTorrent.hs
+++ b/lib/services/amazonka-s3/gen/Amazonka/S3/GetObjectTorrent.hs
@@ -141,7 +141,7 @@ instance Core.AWSRequest GetObjectTorrent where
     Request.s3vhost
       Prelude.. Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetObjectTorrentResponse'
             Prelude.<$> (h Data..#? "x-amz-request-charged")

From ba61dc60574674c8cf1715a5f3be0377e3c37ed8 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:45 +0000
Subject: [PATCH 28/41] amazonka-sagemaker-geospatial: regenerating service

---
 .../gen/Amazonka/SageMakerGeoSpatial/GetTile.hs                 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-sagemaker-geospatial/gen/Amazonka/SageMakerGeoSpatial/GetTile.hs b/lib/services/amazonka-sagemaker-geospatial/gen/Amazonka/SageMakerGeoSpatial/GetTile.hs
index 9ae3d8e2276..7f8337d53c4 100644
--- a/lib/services/amazonka-sagemaker-geospatial/gen/Amazonka/SageMakerGeoSpatial/GetTile.hs
+++ b/lib/services/amazonka-sagemaker-geospatial/gen/Amazonka/SageMakerGeoSpatial/GetTile.hs
@@ -197,7 +197,7 @@ instance Core.AWSRequest GetTile where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetTileResponse'
             Prelude.<$> (Prelude.pure (Prelude.fromEnum s))

From 06229e3847529976cef20c8e918b5314d05b98c0 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 07:17:53 +0000
Subject: [PATCH 29/41] amazonka-workmailmessageflow: regenerating service

---
 .../gen/Amazonka/WorkMailMessageFlow/GetRawMessageContent.hs    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/services/amazonka-workmailmessageflow/gen/Amazonka/WorkMailMessageFlow/GetRawMessageContent.hs b/lib/services/amazonka-workmailmessageflow/gen/Amazonka/WorkMailMessageFlow/GetRawMessageContent.hs
index 3bc70a6a4e3..a530604fa38 100644
--- a/lib/services/amazonka-workmailmessageflow/gen/Amazonka/WorkMailMessageFlow/GetRawMessageContent.hs
+++ b/lib/services/amazonka-workmailmessageflow/gen/Amazonka/WorkMailMessageFlow/GetRawMessageContent.hs
@@ -82,7 +82,7 @@ instance Core.AWSRequest GetRawMessageContent where
   request overrides =
     Request.get (overrides defaultService)
   response =
-    Response.receiveBody
+    Response.receiveStreamingBody
       ( \s h x ->
           GetRawMessageContentResponse'
             Prelude.<$> (Prelude.pure (Prelude.fromEnum s))

From 0ce8e078f2451b46d0a89e48498de4bfd8a9132a Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Fri, 20 Mar 2026 09:13:44 +0000
Subject: [PATCH 30/41] gen: Chip `ParseStreamingBody` out from `AWSRequest`

---
 gen/src/Gen/AST/Data.hs                   |  4 +++
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 31 +++++++++++++++++------
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 74719ca89f8..c1606595de4 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -70,8 +70,12 @@ operationData cfg m o = do
                   EC2 -> AWSRequest.ParseAllXML wrapper
                   Query -> AWSRequest.ParseAllXML wrapper
                   RestXML -> AWSRequest.ParseAllXML wrapper
+        | any fieldStream ys =
+          AWSRequest.ParseStreamingBody responseFieldParsers
         | otherwise = AWSRequest.FigureItOut
 
+      responseFieldParsers = AWSRequest.FigureTheFieldOut <$> ys
+
   cls <-
     pp Print $
       AWSRequest.instanceD
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 6aa0b73bd9c..62ecf699e2e 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -59,9 +59,18 @@ data ResponseParser
     ParseAllJSON
   | -- | Parse the entire resposne as XML, with an optional wrapper.
     ParseAllXML (Maybe Text)
+  | -- | Parse a streaming response from AWS into a
+    -- 'Amazonka.Body.ResponseBody'.
+    ParseStreamingBody [ResponseFieldParser]
   | FigureItOut
   deriving (Show)
 
+-- | How to generate the parser for a single field, for response
+-- parsers which do per-field parsing.
+newtype ResponseFieldParser
+  = FigureTheFieldOut Field
+  deriving (Show)
+
 instanceD ::
   Config ->
   Metadata f ->
@@ -108,16 +117,23 @@ responseE Config {..} p r fs =
       var "Response.receiveXMLWrapper"
         `Exts.app` str wrapper
         `Exts.app` lam (var "Data.parseXML" `Exts.app` var "x")
+    ParseStreamingBody fieldParsers ->
+      var "Response.receiveStreamingBody"
+        `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
     FigureItOut -> Exts.app responseF bdy
   where
     bdy :: Exts.Exp ()
-    bdy = lam . ctorE (identifier r) $ map parseField fs
+    bdy = lam . ctorE (identifier r) $ map parseField' fs
 
     lam :: Exts.Exp () -> Exts.Exp ()
     lam = Exts.lamE [Exts.pvar "s", Exts.pvar "h", Exts.pvar "x"]
 
-    parseField :: Field -> Exts.Exp ()
-    parseField x =
+    parseField :: ResponseFieldParser -> Exts.Exp ()
+    parseField = \case
+      FigureTheFieldOut field -> parseField' field
+
+    parseField' :: Field -> Exts.Exp ()
+    parseField' x =
       case fieldLocation x of
         Just Headers -> parseHeadersE p x
         Just Header -> parseHeadersE p x
@@ -169,11 +185,10 @@ responseE Config {..} p r fs =
     -- etc, particuarly when the body might be totally empty.
     responseF :: Exts.Exp ()
     responseF
-      | any fieldStream fs = var "Response.receiveStreamingBody"
-      | any fieldLitPayload fs = var "Response.receiveBytes"
-      | Just x <- r ^. refResultWrapper = Exts.app (var (suf <> "Wrapper")) (str x)
-      | not $ any fieldBody fs = var "Response.receiveEmpty"
-      | otherwise = var suf
+      | any fieldLitPayload fs = trace "responseF(fieldLitPayload)" $ var "Response.receiveBytes"
+      | Just x <- r ^. refResultWrapper = trace "responseF(Wrapper)" $ Exts.app (var (suf <> "Wrapper")) (str x)
+      | not $ any fieldBody fs = trace "responseF(receiveEmpty)" $ var "Response.receiveEmpty"
+      | otherwise = trace "responseF(var suf)" $ var suf
       where
         suf = "Response.receive" <> Proto.suffix p
 

From 463aaf202bacefe31cfd85a2fa16da967a10e098 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sat, 28 Mar 2026 05:42:55 +0000
Subject: [PATCH 31/41] gen: simplify generation of header parsing

---
 gen/src/Gen/AST/Data/Syntax.hs            |  7 +------
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 20 ++++++++------------
 2 files changed, 9 insertions(+), 18 deletions(-)

diff --git a/gen/src/Gen/AST/Data/Syntax.hs b/gen/src/Gen/AST/Data/Syntax.hs
index 1d455e4be34..a05e6d31638 100644
--- a/gen/src/Gen/AST/Data/Syntax.hs
+++ b/gen/src/Gen/AST/Data/Syntax.hs
@@ -58,15 +58,10 @@ pJE = "Data..:>"
 pJEMay = "Data..?>"
 pJEDef = pXDef
 
-pH, pHMay :: QOp
-pH = "Data..#"
-pHMay = "Data..#?"
-
-pXMap, pXList, pXList1, pHMap :: Exp
+pXMap, pXList, pXList1 :: Exp
 pXMap = var "Data.parseXMLMap"
 pXList = var "Data.parseXMLList"
 pXList1 = var "Data.parseXMLList1"
-pHMap = var "Data.parseHeadersMap"
 
 toX, toXAttr, toJ, toQ, toH :: QOp
 toX = "Data.@="
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 62ecf699e2e..0aacdc30894 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -3,15 +3,11 @@ module Gen.AST.Data.Syntax.AWSRequest where
 import Gen.AST.Data.Field (Field, fieldBody, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
 import Gen.AST.Data.Syntax
   ( ctorE,
-    decodeE,
     funArgsD,
     funD,
     instD,
     justE,
     memberName,
-    pH,
-    pHMap,
-    pHMay,
     pJE,
     pJEDef,
     pJEMay,
@@ -135,8 +131,8 @@ responseE Config {..} p r fs =
     parseField' :: Field -> Exts.Exp ()
     parseField' x =
       case fieldLocation x of
-        Just Headers -> parseHeadersE p x
-        Just Header -> parseHeadersE p x
+        Just Headers -> parseHeadersE (memberName p Output x) (typeOf x)
+        Just Header -> parseHeadersE (memberName p Output x) (typeOf x)
         Just StatusCode -> parseStatusE x
         Just Body | body -> Exts.app pureE (var "x")
         Nothing | body -> Exts.app pureE (var "x")
@@ -192,13 +188,13 @@ responseE Config {..} p r fs =
       where
         suf = "Response.receive" <> Proto.suffix p
 
-parseHeadersE :: Protocol -> Field -> Exts.Exp ()
-parseHeadersE p f
-  | TMap {} <- typeOf f = Exts.appFun pHMap [str n, h]
-  | fieldMaybe f = decodeE h pHMay n
-  | otherwise = decodeE h pH n
+parseHeadersE :: Text -> TType -> Exts.Exp ()
+parseHeadersE headerName = \case
+  TMap {} -> Exts.appFun (var "Data.parseHeadersMap") [n, h]
+  TMaybe {} -> Exts.infixApp h "Data..#?" n
+  _ -> Exts.infixApp h "Data..#" n
   where
-    n = memberName p Output f
+    n = str headerName
     h = var "h"
 
 parseStatusE :: Field -> Exts.Exp ()

From 62641228cc2e068520f98ef729b219e550f59191 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sat, 28 Mar 2026 07:21:22 +0000
Subject: [PATCH 32/41] gen: Define field parser for parsing response headers

---
 gen/src/Gen/AST/Data.hs                   | 22 ++++++++++++--
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 35 +++++++++++++++++++++--
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index c1606595de4..aeee50b6d4b 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -71,10 +71,28 @@ operationData cfg m o = do
                   Query -> AWSRequest.ParseAllXML wrapper
                   RestXML -> AWSRequest.ParseAllXML wrapper
         | any fieldStream ys =
-          AWSRequest.ParseStreamingBody responseFieldParsers
+            AWSRequest.ParseStreamingBody responseFieldParsers
         | otherwise = AWSRequest.FigureItOut
 
-      responseFieldParsers = AWSRequest.FigureTheFieldOut <$> ys
+      responseFieldParsers =
+        ys <&> \f ->
+          case fieldLocation f of
+            -- TODO: Unify the 'Headers' and 'Header' location constructors.
+            Just Headers -> AWSRequest.ParseHeaderField hName hParser
+              where
+                hName = memberName (m ^. protocol) Output f
+                hParser = case typeOf f of
+                  TMap {} -> AWSRequest.HeaderFieldMap
+                  TMaybe {} -> AWSRequest.HeaderFieldOptional
+                  _ -> AWSRequest.HeaderFieldRequired
+            Just Header -> AWSRequest.ParseHeaderField hName hParser
+              where
+                hName = memberName (m ^. protocol) Output f
+                hParser = case typeOf f of
+                  TMap {} -> AWSRequest.HeaderFieldMap
+                  TMaybe {} -> AWSRequest.HeaderFieldOptional
+                  _ -> AWSRequest.HeaderFieldRequired
+            _ -> AWSRequest.FigureTheFieldOut f
 
   cls <-
     pp Print $
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 0aacdc30894..49a32a6a47b 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -1,4 +1,11 @@
-module Gen.AST.Data.Syntax.AWSRequest where
+module Gen.AST.Data.Syntax.AWSRequest
+  ( instanceD,
+    Config (..),
+    ResponseParser (..),
+    ResponseFieldParser (..),
+    HeaderFieldParser (..),
+  )
+where
 
 import Gen.AST.Data.Field (Field, fieldBody, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
 import Gen.AST.Data.Syntax
@@ -63,8 +70,25 @@ data ResponseParser
 
 -- | How to generate the parser for a single field, for response
 -- parsers which do per-field parsing.
-newtype ResponseFieldParser
-  = FigureTheFieldOut Field
+data ResponseFieldParser
+  = -- | Parse the repsonse field from the HTTP response headers named
+    -- like the given 'Text'.
+    ParseHeaderField Text HeaderFieldParser
+  | FigureTheFieldOut Field
+  deriving (Show)
+
+-- | How to parse a single field from the HTTP response headers.
+--
+-- A 'HeaderFieldParser' does not parse a single header, because some
+-- AWS services represent structured data by breaking it across
+-- multiple similarly-named headers.
+data HeaderFieldParser
+  = -- | Parse a required field from headers using @(.#)@.
+    HeaderFieldRequired
+  | -- | Parse an optional field from headers using @(.#?)@.
+    HeaderFieldOptional
+  | -- | Parse a map field from headers using @parseHeadersMap@.
+    HeaderFieldMap
   deriving (Show)
 
 instanceD ::
@@ -126,6 +150,11 @@ responseE Config {..} p r fs =
 
     parseField :: ResponseFieldParser -> Exts.Exp ()
     parseField = \case
+      ParseHeaderField hName hField -> case hField of
+        HeaderFieldRequired -> Exts.infixApp (var "h") "Data..#" (str hName)
+        HeaderFieldOptional -> Exts.infixApp (var "h") "Data..#?" (str hName)
+        HeaderFieldMap ->
+          Exts.appFun (var "Data.parseHeadersMap") [str hName, var "h"]
       FigureTheFieldOut field -> parseField' field
 
     parseField' :: Field -> Exts.Exp ()

From d6fabea75c66b5ad5a7586f6ff4471237b8f454f Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sat, 28 Mar 2026 09:25:58 +0000
Subject: [PATCH 33/41] gen: Simplify `Location` type

---
 gen/src/Gen/AST/Data.hs                   |  8 --------
 gen/src/Gen/AST/Data/Field.hs             | 10 ++--------
 gen/src/Gen/AST/Data/Instance.hs          |  4 ++--
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs |  1 -
 gen/src/Gen/Types/Service.hs              | 18 +++++++++++-------
 5 files changed, 15 insertions(+), 26 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index aeee50b6d4b..5d3aae10e02 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -77,7 +77,6 @@ operationData cfg m o = do
       responseFieldParsers =
         ys <&> \f ->
           case fieldLocation f of
-            -- TODO: Unify the 'Headers' and 'Header' location constructors.
             Just Headers -> AWSRequest.ParseHeaderField hName hParser
               where
                 hName = memberName (m ^. protocol) Output f
@@ -85,13 +84,6 @@ operationData cfg m o = do
                   TMap {} -> AWSRequest.HeaderFieldMap
                   TMaybe {} -> AWSRequest.HeaderFieldOptional
                   _ -> AWSRequest.HeaderFieldRequired
-            Just Header -> AWSRequest.ParseHeaderField hName hParser
-              where
-                hName = memberName (m ^. protocol) Output f
-                hParser = case typeOf f of
-                  TMap {} -> AWSRequest.HeaderFieldMap
-                  TMaybe {} -> AWSRequest.HeaderFieldOptional
-                  _ -> AWSRequest.HeaderFieldRequired
             _ -> AWSRequest.FigureTheFieldOut f
 
   cls <-
diff --git a/gen/src/Gen/AST/Data/Field.hs b/gen/src/Gen/AST/Data/Field.hs
index 6480790fc84..7db1489dbc3 100644
--- a/gen/src/Gen/AST/Data/Field.hs
+++ b/gen/src/Gen/AST/Data/Field.hs
@@ -50,13 +50,7 @@ instance TypeOf Field where
           TList {} -> True
           _ -> False
 
-      isHeader =
-        fieldLocation f
-          `elem` map
-            Just
-            [ Headers,
-              Header
-            ]
+      isHeader = fieldLocation f == Just Headers
 
       ref = f ^. fieldRef
       typ = fmap unBase64 (typeOf ref)
@@ -71,7 +65,7 @@ instance HasInfo Field where
 -- FIXME: Can just add the metadata to field as well since
 -- the protocol/timestamp are passed in everywhere in the .Syntax module.
 mkFields ::
-  HasMetadata a Identity =>
+  (HasMetadata a Identity) =>
   a ->
   Solved ->
   StructF (Shape Solved) ->
diff --git a/gen/src/Gen/AST/Data/Instance.hs b/gen/src/Gen/AST/Data/Instance.hs
index 7f74294f541..cdb07318f34 100644
--- a/gen/src/Gen/AST/Data/Instance.hs
+++ b/gen/src/Gen/AST/Data/Instance.hs
@@ -130,7 +130,7 @@ requestInsts m oname h r fs = do
       where
         merged xs =
           let ys =
-                map Right (satisfies [Querystring] fs) <> xs
+                map Right (satisfies [QueryString] fs) <> xs
                   ++ map Left protocolQuery
            in case List.find f is of
                 Just (ToQuery zs) -> ToQuery (ys <> zs)
@@ -217,7 +217,7 @@ requestInsts m oname h r fs = do
         v = ("Version", Just version)
 
     headers :: [Field]
-    headers = satisfies [Header, Headers] fs
+    headers = [f | f <- fs, fieldLocation f == Just Headers]
 
     target = (<> ("." <> action)) <$> m ^. targetPrefix
 
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 49a32a6a47b..1cd64850177 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -161,7 +161,6 @@ responseE Config {..} p r fs =
     parseField' x =
       case fieldLocation x of
         Just Headers -> parseHeadersE (memberName p Output x) (typeOf x)
-        Just Header -> parseHeadersE (memberName p Output x) (typeOf x)
         Just StatusCode -> parseStatusE x
         Just Body | body -> Exts.app pureE (var "x")
         Nothing | body -> Exts.app pureE (var "x")
diff --git a/gen/src/Gen/Types/Service.hs b/gen/src/Gen/Types/Service.hs
index 7dfd215aea1..03acbcf93d3 100644
--- a/gen/src/Gen/Types/Service.hs
+++ b/gen/src/Gen/Types/Service.hs
@@ -97,18 +97,22 @@ instance ToJSON Checksum where
 
 data Location
   = Headers
-  | Header
   | Uri
-  | Querystring
+  | QueryString
   | StatusCode
-  | Body
+  | -- | Not present in @botocore@, but we explicitly annotate fields
+    -- with it.
+    Body
   deriving stock (Eq, Show, Generic)
 
 instance FromJSON Location where
-  parseJSON = gParseJSON' camel
-
-instance ToJSON Location where
-  toJSON = gToJSON' camel
+  parseJSON = Aeson.withText "Location" $ \t -> case t of
+    "header" -> pure Headers -- Present in e.g. accessanalyzer
+    "headers" -> pure Headers -- Present in e.g. dataexchange
+    "querystring" -> pure QueryString
+    "statusCode" -> pure StatusCode
+    "uri" -> pure Uri
+    _ -> fail $ "Unknown location: " <> show t
 
 data XML = XML'
   { _xmlPrefix :: Maybe Text,

From c36eec75a5db653c33d0377b77e0423126e48530 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sat, 28 Mar 2026 10:54:44 +0000
Subject: [PATCH 34/41] gen: Rename receiver function type

---
 gen/src/Gen/AST/Data.hs                   | 20 +++++-----
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 46 ++++++++++++-----------
 2 files changed, 35 insertions(+), 31 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 5d3aae10e02..34dfeec5e12 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -58,20 +58,20 @@ operationData cfg m o = do
             ToElement {} -> Just "XML"
             _ -> Nothing
 
-      responseParser
-        | null ys = AWSRequest.ParseNull
+      responseReceiver
+        | null ys = AWSRequest.ReceiveNull
         | isShared . extract $ yr ^. refAnn,
           all fieldBody ys =
             let wrapper = yr ^. refResultWrapper
              in case m ^. protocol of
-                  APIGateway -> AWSRequest.ParseAllJSON
-                  JSON -> AWSRequest.ParseAllJSON
-                  RestJSON -> AWSRequest.ParseAllJSON
-                  EC2 -> AWSRequest.ParseAllXML wrapper
-                  Query -> AWSRequest.ParseAllXML wrapper
-                  RestXML -> AWSRequest.ParseAllXML wrapper
+                  APIGateway -> AWSRequest.ReceiveJsonAll
+                  JSON -> AWSRequest.ReceiveJsonAll
+                  RestJSON -> AWSRequest.ReceiveJsonAll
+                  EC2 -> AWSRequest.ReceiveXmlAll wrapper
+                  Query -> AWSRequest.ReceiveXmlAll wrapper
+                  RestXML -> AWSRequest.ReceiveXmlAll wrapper
         | any fieldStream ys =
-            AWSRequest.ParseStreamingBody responseFieldParsers
+            AWSRequest.ReceiveStreamingBody responseFieldParsers
         | otherwise = AWSRequest.FigureItOut
 
       responseFieldParsers =
@@ -99,7 +99,7 @@ operationData cfg m o = do
                   <|> (cfg ^. operationPlugins . Lens.at (mkId "*")),
             requestFunction,
             responseType = identifier yr,
-            responseParser,
+            responseReceiver,
             serviceConfig = m ^. serviceConfig
           }
         (m ^. metadata)
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 1cd64850177..43a281c1ad6 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -1,7 +1,7 @@
 module Gen.AST.Data.Syntax.AWSRequest
   ( instanceD,
     Config (..),
-    ResponseParser (..),
+    ResponseReceiver (..),
     ResponseFieldParser (..),
     HeaderFieldParser (..),
   )
@@ -44,8 +44,8 @@ data Config = Config
     -- | Name of the data type we generate for the botocore output
     -- shape that corresponds to 'requestType'.
     responseType :: Id,
-    -- | How to parse the response from AWS.
-    responseParser :: ResponseParser,
+    -- | How to receive and parse the response from AWS.
+    responseReceiver :: ResponseReceiver,
     -- | Name of the service config value to use by default. As of
     -- 2025-11, always @"defaultService"@; the parser for 'Metadata'
     -- would override the service abbrev in all cases.
@@ -53,18 +53,21 @@ data Config = Config
   }
   deriving (Show)
 
--- | How to generate the parser for AWS's response to an API call.
-data ResponseParser
-  = -- | Perform no parsing and return an empty response. The response
-    -- constructor in 'responseType' must take no arguments.
-    ParseNull
-  | -- | Parse the entire response as JSON.
-    ParseAllJSON
-  | -- | Parse the entire resposne as XML, with an optional wrapper.
-    ParseAllXML (Maybe Text)
-  | -- | Parse a streaming response from AWS into a
-    -- 'Amazonka.Body.ResponseBody'.
-    ParseStreamingBody [ResponseFieldParser]
+-- | Which Amazonka function should be used to parse AWS's response to
+-- an API call, and additional arguments are necessary to actually
+-- perform the parse.
+data ResponseReceiver
+  = -- | Perform no parsing and return an empty response using
+    -- @receiveNull@. The response constructor in 'responseType' must
+    -- take no arguments.
+    ReceiveNull
+  | -- | Parse the entire response as JSON using @receiveJSON@.
+    ReceiveJsonAll
+  | -- | Parse the entire response as (optionally wrapped) XML, using
+    -- @receiveXML@ or @receiveXMLWrapper@.
+    ReceiveXmlAll (Maybe Text)
+  | -- | Parse a streaming response from AWS using @receiveStreamingBody@.
+    ReceiveStreamingBody [ResponseFieldParser]
   | FigureItOut
   deriving (Show)
 
@@ -125,19 +128,20 @@ requestD Config {..} =
 
 responseE :: Config -> Protocol -> Ref -> [Field] -> Exts.Exp ()
 responseE Config {..} p r fs =
-  case responseParser of
-    ParseNull -> var "Response.receiveNull" `Exts.app` var (ctorId responseType)
-    ParseAllJSON ->
+  case responseReceiver of
+    ReceiveNull ->
+      var "Response.receiveNull" `Exts.app` var (ctorId responseType)
+    ReceiveJsonAll ->
       var "Response.receiveJSON"
         `Exts.app` lam (var "Data.eitherParseJSON" `Exts.app` var "x")
-    ParseAllXML Nothing ->
+    ReceiveXmlAll Nothing ->
       var "Response.receiveXML"
         `Exts.app` lam (var "Data.parseXML" `Exts.app` var "x")
-    ParseAllXML (Just wrapper) ->
+    ReceiveXmlAll (Just wrapper) ->
       var "Response.receiveXMLWrapper"
         `Exts.app` str wrapper
         `Exts.app` lam (var "Data.parseXML" `Exts.app` var "x")
-    ParseStreamingBody fieldParsers ->
+    ReceiveStreamingBody fieldParsers ->
       var "Response.receiveStreamingBody"
         `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
     FigureItOut -> Exts.app responseF bdy

From 47cfa66c2bfee98bb2448aa2e2f512044d8c7e05 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Sun, 29 Mar 2026 12:07:55 +0000
Subject: [PATCH 35/41] gen: Add explicit constructor for `receiveBytes`
 parsing

---
 gen/src/Gen/AST/Data.hs                   | 2 ++
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 34dfeec5e12..205ffd96ee8 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -72,6 +72,8 @@ operationData cfg m o = do
                   RestXML -> AWSRequest.ReceiveXmlAll wrapper
         | any fieldStream ys =
             AWSRequest.ReceiveStreamingBody responseFieldParsers
+        | any fieldLitPayload ys =
+            AWSRequest.ReceiveBytes responseFieldParsers
         | otherwise = AWSRequest.FigureItOut
 
       responseFieldParsers =
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 43a281c1ad6..88856bec4ce 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -68,6 +68,9 @@ data ResponseReceiver
     ReceiveXmlAll (Maybe Text)
   | -- | Parse a streaming response from AWS using @receiveStreamingBody@.
     ReceiveStreamingBody [ResponseFieldParser]
+  | -- | Parse a response from AWS, accepting the body as an unparsed
+    -- 'ByteString'. Uses @receiveBytes@.
+    ReceiveBytes [ResponseFieldParser]
   | FigureItOut
   deriving (Show)
 
@@ -144,6 +147,9 @@ responseE Config {..} p r fs =
     ReceiveStreamingBody fieldParsers ->
       var "Response.receiveStreamingBody"
         `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
+    ReceiveBytes fieldParsers ->
+      var "Response.receiveBytes"
+        `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
     FigureItOut -> Exts.app responseF bdy
   where
     bdy :: Exts.Exp ()
@@ -213,7 +219,6 @@ responseE Config {..} p r fs =
     -- etc, particuarly when the body might be totally empty.
     responseF :: Exts.Exp ()
     responseF
-      | any fieldLitPayload fs = trace "responseF(fieldLitPayload)" $ var "Response.receiveBytes"
       | Just x <- r ^. refResultWrapper = trace "responseF(Wrapper)" $ Exts.app (var (suf <> "Wrapper")) (str x)
       | not $ any fieldBody fs = trace "responseF(receiveEmpty)" $ var "Response.receiveEmpty"
       | otherwise = trace "responseF(var suf)" $ var suf

From 66b8f81939ccc4305cae5b1df0a3d0931b065a7b Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Tue, 31 Mar 2026 11:19:32 +0000
Subject: [PATCH 36/41] gen: Chip out parsing of fieldwise (wrapped) XML

---
 gen/src/Gen/AST/Data.hs                   | 30 ++++++++++++++++-------
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 11 ++++++++-
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 205ffd96ee8..3ec676652b0 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -61,20 +61,32 @@ operationData cfg m o = do
       responseReceiver
         | null ys = AWSRequest.ReceiveNull
         | isShared . extract $ yr ^. refAnn,
-          all fieldBody ys =
-            let wrapper = yr ^. refResultWrapper
-             in case m ^. protocol of
-                  APIGateway -> AWSRequest.ReceiveJsonAll
-                  JSON -> AWSRequest.ReceiveJsonAll
-                  RestJSON -> AWSRequest.ReceiveJsonAll
-                  EC2 -> AWSRequest.ReceiveXmlAll wrapper
-                  Query -> AWSRequest.ReceiveXmlAll wrapper
-                  RestXML -> AWSRequest.ReceiveXmlAll wrapper
+          all fieldBody ys = case m ^. protocol of
+            APIGateway -> AWSRequest.ReceiveJsonAll
+            JSON -> AWSRequest.ReceiveJsonAll
+            RestJSON -> AWSRequest.ReceiveJsonAll
+            EC2 -> AWSRequest.ReceiveXmlAll wrapper
+            Query -> AWSRequest.ReceiveXmlAll wrapper
+            RestXML -> AWSRequest.ReceiveXmlAll wrapper
         | any fieldStream ys =
             AWSRequest.ReceiveStreamingBody responseFieldParsers
         | any fieldLitPayload ys =
             AWSRequest.ReceiveBytes responseFieldParsers
+        | -- Check if we should parse wrapped XML before considering
+          -- ReceiveEmpty, because fieldBody is not true for fields
+          -- parsed from within wrapped XML.
+          isXml && isJust wrapper =
+            AWSRequest.ReceiveXml wrapper responseFieldParsers
         | otherwise = AWSRequest.FigureItOut
+        where
+          wrapper = yr ^. refResultWrapper
+          isXml = case m ^. protocol of
+            APIGateway -> False
+            JSON -> False
+            RestJSON -> False
+            EC2 -> True
+            Query -> True
+            RestXML -> True
 
       responseFieldParsers =
         ys <&> \f ->
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 88856bec4ce..82774183818 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -71,6 +71,9 @@ data ResponseReceiver
   | -- | Parse a response from AWS, accepting the body as an unparsed
     -- 'ByteString'. Uses @receiveBytes@.
     ReceiveBytes [ResponseFieldParser]
+  | -- | Parse (optionally wrapped) XML response by field using either
+    -- @receiveXML@ or @receiveXMLWrapper@.
+    ReceiveXml (Maybe Text) [ResponseFieldParser]
   | FigureItOut
   deriving (Show)
 
@@ -150,6 +153,13 @@ responseE Config {..} p r fs =
     ReceiveBytes fieldParsers ->
       var "Response.receiveBytes"
         `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
+    ReceiveXml Nothing fieldParsers ->
+      var "Response.receiveXML"
+        `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
+    ReceiveXml (Just wrapper) fieldParsers ->
+      var "Response.receiveXMLWrapper"
+        `Exts.app` str wrapper
+        `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
     FigureItOut -> Exts.app responseF bdy
   where
     bdy :: Exts.Exp ()
@@ -219,7 +229,6 @@ responseE Config {..} p r fs =
     -- etc, particuarly when the body might be totally empty.
     responseF :: Exts.Exp ()
     responseF
-      | Just x <- r ^. refResultWrapper = trace "responseF(Wrapper)" $ Exts.app (var (suf <> "Wrapper")) (str x)
       | not $ any fieldBody fs = trace "responseF(receiveEmpty)" $ var "Response.receiveEmpty"
       | otherwise = trace "responseF(var suf)" $ var suf
       where

From 055e8f15950215da637509f8e34810f5e5e18b0a Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Tue, 31 Mar 2026 11:29:14 +0000
Subject: [PATCH 37/41] gen: Chip out check for receiveEmpty

---
 gen/src/Gen/AST/Data.hs                   |  2 ++
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 13 +++++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 3ec676652b0..dc29d334e5a 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -77,6 +77,8 @@ operationData cfg m o = do
           -- parsed from within wrapped XML.
           isXml && isJust wrapper =
             AWSRequest.ReceiveXml wrapper responseFieldParsers
+        | not $ any fieldBody ys =
+            AWSRequest.ReceiveEmpty responseFieldParsers
         | otherwise = AWSRequest.FigureItOut
         where
           wrapper = yr ^. refResultWrapper
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 82774183818..6e5d8803074 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -7,7 +7,7 @@ module Gen.AST.Data.Syntax.AWSRequest
   )
 where
 
-import Gen.AST.Data.Field (Field, fieldBody, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
+import Gen.AST.Data.Field (Field, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
 import Gen.AST.Data.Syntax
   ( ctorE,
     funArgsD,
@@ -74,6 +74,10 @@ data ResponseReceiver
   | -- | Parse (optionally wrapped) XML response by field using either
     -- @receiveXML@ or @receiveXMLWrapper@.
     ReceiveXml (Maybe Text) [ResponseFieldParser]
+  | -- | Parse an empty response using @receiveEmpty@. The body will
+    -- not be available to parse and all fields will come from headers
+    -- or status.
+    ReceiveEmpty [ResponseFieldParser]
   | FigureItOut
   deriving (Show)
 
@@ -160,6 +164,9 @@ responseE Config {..} p r fs =
       var "Response.receiveXMLWrapper"
         `Exts.app` str wrapper
         `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
+    ReceiveEmpty fieldParsers ->
+      var "Response.receiveEmpty"
+        `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
     FigureItOut -> Exts.app responseF bdy
   where
     bdy :: Exts.Exp ()
@@ -228,9 +235,7 @@ responseE Config {..} p r fs =
     -- FIXME: take method into account for responses, such as HEAD
     -- etc, particuarly when the body might be totally empty.
     responseF :: Exts.Exp ()
-    responseF
-      | not $ any fieldBody fs = trace "responseF(receiveEmpty)" $ var "Response.receiveEmpty"
-      | otherwise = trace "responseF(var suf)" $ var suf
+    responseF = trace "responseF(var suf)" $ var suf
       where
         suf = "Response.receive" <> Proto.suffix p
 

From f255c3deeffe0b0aa6bc0ad84c7c2397456b098d Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Thu, 23 Apr 2026 10:42:07 +0000
Subject: [PATCH 38/41] gen: Chip out fieldwise JSON parsing

---
 gen/src/Gen/AST/Data.hs                   | 11 +++++++++++
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs |  7 ++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index dc29d334e5a..02e176119e4 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -79,9 +79,20 @@ operationData cfg m o = do
             AWSRequest.ReceiveXml wrapper responseFieldParsers
         | not $ any fieldBody ys =
             AWSRequest.ReceiveEmpty responseFieldParsers
+        | isJson =
+            AWSRequest.ReceiveJson responseFieldParsers
         | otherwise = AWSRequest.FigureItOut
         where
           wrapper = yr ^. refResultWrapper
+
+          isJson = case m ^. protocol of
+            APIGateway -> True
+            JSON -> True
+            RestJSON -> True
+            EC2 -> False
+            Query -> False
+            RestXML -> False
+
           isXml = case m ^. protocol of
             APIGateway -> False
             JSON -> False
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 6e5d8803074..8713c590c94 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -71,7 +71,9 @@ data ResponseReceiver
   | -- | Parse a response from AWS, accepting the body as an unparsed
     -- 'ByteString'. Uses @receiveBytes@.
     ReceiveBytes [ResponseFieldParser]
-  | -- | Parse (optionally wrapped) XML response by field using either
+  | -- | Parse a JSON response from AWS fieldwise using @receiveJSON@.
+    ReceiveJson [ResponseFieldParser]
+  | -- | Parse (optionally wrapped) XML response fieldwise using either
     -- @receiveXML@ or @receiveXMLWrapper@.
     ReceiveXml (Maybe Text) [ResponseFieldParser]
   | -- | Parse an empty response using @receiveEmpty@. The body will
@@ -157,6 +159,9 @@ responseE Config {..} p r fs =
     ReceiveBytes fieldParsers ->
       var "Response.receiveBytes"
         `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
+    ReceiveJson fieldParsers ->
+      var "Response.receiveJSON"
+        `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
     ReceiveXml Nothing fieldParsers ->
       var "Response.receiveXML"
         `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)

From b45c03e77f665eaa21f75673390eef94464a39d3 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Thu, 23 Apr 2026 11:15:29 +0000
Subject: [PATCH 39/41] gen: Complete the removal of `responseF`

---
 gen/src/Gen/AST/Data.hs                   | 17 +++++++++---
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 34 ++++-------------------
 2 files changed, 18 insertions(+), 33 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 02e176119e4..3f988f8536b 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -68,20 +68,29 @@ operationData cfg m o = do
             EC2 -> AWSRequest.ReceiveXmlAll wrapper
             Query -> AWSRequest.ReceiveXmlAll wrapper
             RestXML -> AWSRequest.ReceiveXmlAll wrapper
+        -- FIXME: take method into account for responses, such as HEAD
+        -- etc, particuarly when the body might be totally empty.
         | any fieldStream ys =
             AWSRequest.ReceiveStreamingBody responseFieldParsers
         | any fieldLitPayload ys =
             AWSRequest.ReceiveBytes responseFieldParsers
         | -- Check if we should parse wrapped XML before considering
-          -- ReceiveEmpty, because fieldBody is not true for fields
+          -- ReceiveEmpty, because fieldBody is false for fields
           -- parsed from within wrapped XML.
           isXml && isJust wrapper =
             AWSRequest.ReceiveXml wrapper responseFieldParsers
-        | not $ any fieldBody ys =
+        | -- Then check for responses that don't use the field body,
+          -- to avoid trying to `receiveXml` on API calls where AWS
+          -- might send us an empty body.
+          not $ any fieldBody ys =
             AWSRequest.ReceiveEmpty responseFieldParsers
+        | -- Finally, check for unwrapped XML, parsed fieldwise.
+          isXml && isNothing wrapper =
+            AWSRequest.ReceiveXml wrapper responseFieldParsers
         | isJson =
             AWSRequest.ReceiveJson responseFieldParsers
-        | otherwise = AWSRequest.FigureItOut
+        | otherwise =
+            error "Gen.AST.Data.operationData(responseReceiver): don't know how to parse"
         where
           wrapper = yr ^. refResultWrapper
 
@@ -130,7 +139,7 @@ operationData cfg m o = do
             serviceConfig = m ^. serviceConfig
           }
         (m ^. metadata)
-        (yr, ys)
+        ys
   mpage <- pagerFields m o >>= traverse (pp Print . pagerD xn)
 
   yis' <- renderInsts p yn (responseInsts ys)
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index 8713c590c94..cc01193643f 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -14,7 +14,6 @@ import Gen.AST.Data.Syntax
     funD,
     instD,
     justE,
-    memberName,
     pJE,
     pJEDef,
     pJEMay,
@@ -27,7 +26,6 @@ import Gen.AST.Data.Syntax
     var,
   )
 import Gen.Prelude
-import qualified Gen.Protocol as Proto
 import Gen.Types hiding (Config, serviceConfig)
 import qualified Language.Haskell.Exts as Exts
 
@@ -80,7 +78,6 @@ data ResponseReceiver
     -- not be available to parse and all fields will come from headers
     -- or status.
     ReceiveEmpty [ResponseFieldParser]
-  | FigureItOut
   deriving (Show)
 
 -- | How to generate the parser for a single field, for response
@@ -109,14 +106,14 @@ data HeaderFieldParser
 instanceD ::
   Config ->
   Metadata f ->
-  (Ref, [Field]) ->
+  [Field] ->
   Exts.Decl ()
-instanceD c@Config {requestType} m (responseRef, responseFields) =
+instanceD c@Config {requestType} m responseFields =
   instD "Core.AWSRequest" requestType $
     Just
       [ awsResponseD c,
         requestD c,
-        funD "response" (responseE c (m ^. protocol) responseRef responseFields)
+        funD "response" (responseE c (m ^. protocol) responseFields)
       ]
 
 awsResponseD :: Config -> Exts.InstDecl ()
@@ -138,8 +135,8 @@ requestD Config {..} =
         (var $ "Request." <> requestFunction)
         (Exts.app (var "overrides") (var serviceConfig))
 
-responseE :: Config -> Protocol -> Ref -> [Field] -> Exts.Exp ()
-responseE Config {..} p r fs =
+responseE :: Config -> Protocol -> [Field] -> Exts.Exp ()
+responseE Config {..} p fs =
   case responseReceiver of
     ReceiveNull ->
       var "Response.receiveNull" `Exts.app` var (ctorId responseType)
@@ -172,11 +169,7 @@ responseE Config {..} p r fs =
     ReceiveEmpty fieldParsers ->
       var "Response.receiveEmpty"
         `Exts.app` lam (ctorE responseType $ map parseField fieldParsers)
-    FigureItOut -> Exts.app responseF bdy
   where
-    bdy :: Exts.Exp ()
-    bdy = lam . ctorE (identifier r) $ map parseField' fs
-
     lam :: Exts.Exp () -> Exts.Exp ()
     lam = Exts.lamE [Exts.pvar "s", Exts.pvar "h", Exts.pvar "x"]
 
@@ -192,7 +185,6 @@ responseE Config {..} p r fs =
     parseField' :: Field -> Exts.Exp ()
     parseField' x =
       case fieldLocation x of
-        Just Headers -> parseHeadersE (memberName p Output x) (typeOf x)
         Just StatusCode -> parseStatusE x
         Just Body | body -> Exts.app pureE (var "x")
         Nothing | body -> Exts.app pureE (var "x")
@@ -237,22 +229,6 @@ responseE Config {..} p r fs =
 
     body = any fieldStream fs
 
-    -- FIXME: take method into account for responses, such as HEAD
-    -- etc, particuarly when the body might be totally empty.
-    responseF :: Exts.Exp ()
-    responseF = trace "responseF(var suf)" $ var suf
-      where
-        suf = "Response.receive" <> Proto.suffix p
-
-parseHeadersE :: Text -> TType -> Exts.Exp ()
-parseHeadersE headerName = \case
-  TMap {} -> Exts.appFun (var "Data.parseHeadersMap") [n, h]
-  TMaybe {} -> Exts.infixApp h "Data..#?" n
-  _ -> Exts.infixApp h "Data..#" n
-  where
-    n = str headerName
-    h = var "h"
-
 parseStatusE :: Field -> Exts.Exp ()
 parseStatusE f
   | fieldMaybe f = Exts.app pureE (Exts.app justE v)

From 5e0510bd99481ae89a79f72e33d5f51a71a371fb Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Thu, 23 Apr 2026 11:22:50 +0000
Subject: [PATCH 40/41] gen: Remove dead code in `parseStatusE` and inline

The guard for `fieldMaybe` is never hit in any model
---
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index cc01193643f..a2be25bf9a6 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -7,7 +7,7 @@ module Gen.AST.Data.Syntax.AWSRequest
   )
 where
 
-import Gen.AST.Data.Field (Field, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldMaybe, fieldPayload, fieldStream)
+import Gen.AST.Data.Field (Field, fieldIsParam, fieldLit, fieldLitPayload, fieldLocation, fieldPayload, fieldStream)
 import Gen.AST.Data.Syntax
   ( ctorE,
     funArgsD,
@@ -185,7 +185,8 @@ responseE Config {..} p fs =
     parseField' :: Field -> Exts.Exp ()
     parseField' x =
       case fieldLocation x of
-        Just StatusCode -> parseStatusE x
+        Just StatusCode ->
+          pureE `Exts.app` Exts.paren (var "Prelude.fromEnum" `Exts.app` var "s")
         Just Body | body -> Exts.app pureE (var "x")
         Nothing | body -> Exts.app pureE (var "x")
         _ -> parseProto x
@@ -228,10 +229,3 @@ responseE Config {..} p fs =
             _ -> var "Data.parseXML"
 
     body = any fieldStream fs
-
-parseStatusE :: Field -> Exts.Exp ()
-parseStatusE f
-  | fieldMaybe f = Exts.app pureE (Exts.app justE v)
-  | otherwise = Exts.app pureE v
-  where
-    v = Exts.paren $ Exts.app (var "Prelude.fromEnum") (var "s")

From 9e7315b08ebd88b04420dcc09c92c46b4db1d803 Mon Sep 17 00:00:00 2001
From: Jack Kelly <jack@jackkelly.name>
Date: Thu, 23 Apr 2026 11:26:35 +0000
Subject: [PATCH 41/41] fixup! gen: Define field parser for parsing response
 headers

---
 gen/src/Gen/AST/Data.hs                   | 2 +-
 gen/src/Gen/AST/Data/Syntax/AWSRequest.hs | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/gen/src/Gen/AST/Data.hs b/gen/src/Gen/AST/Data.hs
index 3f988f8536b..e9b6df628f0 100644
--- a/gen/src/Gen/AST/Data.hs
+++ b/gen/src/Gen/AST/Data.hs
@@ -113,7 +113,7 @@ operationData cfg m o = do
       responseFieldParsers =
         ys <&> \f ->
           case fieldLocation f of
-            Just Headers -> AWSRequest.ParseHeaderField hName hParser
+            Just Headers -> AWSRequest.ParseHeader hName hParser
               where
                 hName = memberName (m ^. protocol) Output f
                 hParser = case typeOf f of
diff --git a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
index a2be25bf9a6..391e5e53a5b 100644
--- a/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
+++ b/gen/src/Gen/AST/Data/Syntax/AWSRequest.hs
@@ -85,7 +85,7 @@ data ResponseReceiver
 data ResponseFieldParser
   = -- | Parse the repsonse field from the HTTP response headers named
     -- like the given 'Text'.
-    ParseHeaderField Text HeaderFieldParser
+    ParseHeader Text HeaderFieldParser
   | FigureTheFieldOut Field
   deriving (Show)
 
@@ -175,7 +175,7 @@ responseE Config {..} p fs =
 
     parseField :: ResponseFieldParser -> Exts.Exp ()
     parseField = \case
-      ParseHeaderField hName hField -> case hField of
+      ParseHeader hName hField -> case hField of
         HeaderFieldRequired -> Exts.infixApp (var "h") "Data..#" (str hName)
         HeaderFieldOptional -> Exts.infixApp (var "h") "Data..#?" (str hName)
         HeaderFieldMap ->