From da01adb212da59ffd8f4b13b9582a1523c730cc5 Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Fri, 19 Dec 2025 13:26:28 +0400
Subject: [PATCH 1/7] agent: async command to set connection short link
 (setConnShortLinkAsync)

---
 src/Simplex/Messaging/Agent.hs          | 15 +++++++++++++++
 src/Simplex/Messaging/Agent/Protocol.hs | 16 ++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/Simplex/Messaging/Agent.hs b/src/Simplex/Messaging/Agent.hs
index 3130e0227..a10868653 100644
--- a/src/Simplex/Messaging/Agent.hs
+++ b/src/Simplex/Messaging/Agent.hs
@@ -49,6 +49,7 @@ module Simplex.Messaging.Agent
     deleteUser,
     connRequestPQSupport,
     createConnectionAsync,
+    setConnShortLinkAsync,
     joinConnectionAsync,
     allowConnectionAsync,
     acceptContactAsync,
@@ -345,6 +346,11 @@ createConnectionAsync :: ConnectionModeI c => AgentClient -> UserId -> ACorrId -
 createConnectionAsync c userId aCorrId enableNtfs = withAgentEnv c .:. newConnAsync c userId aCorrId enableNtfs
 {-# INLINE createConnectionAsync #-}
 
+-- | Create or update user's contact connection short link asynchronously, synchronous response is the short link
+setConnShortLinkAsync :: AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AE ()
+setConnShortLinkAsync c = withAgentEnv c .::. setConnShortLinkAsync' c
+{-# INLINE setConnShortLinkAsync #-}
+
 -- | Join SMP agent connection (JOIN command) asynchronously, synchronous response is new connection id
 joinConnectionAsync :: AgentClient -> UserId -> ACorrId -> Bool -> ConnectionRequestUri c -> ConnInfo -> PQSupport -> SubscriptionMode -> AE ConnId
 joinConnectionAsync c userId aCorrId enableNtfs = withAgentEnv c .:: joinConnAsync c userId aCorrId enableNtfs
@@ -886,6 +892,11 @@ checkClientNotices AgentClient {clientNotices, presetServers} (ProtoServerWithAu
         when (maybe True (ts <) expires_) $
           throwError NOTICE {server = safeDecodeUtf8 $ strEncode $ L.head host, preset = isNothing srvKey, expiresAt = roundedToUTCTime <$> expires_}
 
+setConnShortLinkAsync' :: AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AM ()
+setConnShortLinkAsync' c corrId connId cMode userLinkData clientData =
+  -- enqueue command SLINK
+  undefined
+
 setConnShortLink' :: AgentClient -> NetworkRequestMode -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AM (ConnShortLink c)
 setConnShortLink' c nm connId cMode userLinkData clientData =
   withConnLock c connId "setConnShortLink" $ do
@@ -1657,6 +1668,10 @@ runCommandProcessing c@AgentClient {subQ} connId server_ Worker {doWork} = do
           tryCommand . withNextSrv c userId storageSrvs triedHosts [] $ \srv -> do
             (CCLink cReq _, service) <- newRcvConnSrv c NRMBackground userId connId enableNtfs cMode Nothing Nothing pqEnc subMode srv
             notify $ INV (ACR cMode cReq) service
+        SLINK {} ->
+          -- create link (reuse setConnShortLink')
+          -- notify - LINK
+          undefined
         JOIN enableNtfs (ACR _ cReq@(CRInvitationUri ConnReqUriData {crSmpQueues = q :| _} _)) pqEnc subMode connInfo -> noServer $ do
           triedHosts <- newTVarIO S.empty
           tryCommand . withNextSrv c userId storageSrvs triedHosts [qServer q] $ \srv -> do
diff --git a/src/Simplex/Messaging/Agent/Protocol.hs b/src/Simplex/Messaging/Agent/Protocol.hs
index 05ebc1b27..4946fd8b0 100644
--- a/src/Simplex/Messaging/Agent/Protocol.hs
+++ b/src/Simplex/Messaging/Agent/Protocol.hs
@@ -382,6 +382,7 @@ type SndQueueSecured = Bool
 -- | Parameterized type for SMP agent events
 data AEvent (e :: AEntity) where
   INV :: AConnectionRequestUri -> Maybe ClientServiceId -> AEvent AEConn
+  LINK :: AConnShortLink -> AEvent AEConn
   CONF :: ConfirmationId -> PQSupport -> [SMPServer] -> ConnInfo -> AEvent AEConn -- ConnInfo is from sender, [SMPServer] will be empty only in v1 handshake
   REQ :: InvitationId -> PQSupport -> NonEmpty SMPServer -> ConnInfo -> AEvent AEConn -- ConnInfo is from sender
   INFO :: PQSupport -> ConnInfo -> AEvent AEConn
@@ -435,6 +436,7 @@ deriving instance Show AEvtTag
 
 data ACommand
   = NEW Bool AConnectionMode InitialKeys SubscriptionMode -- response INV
+  | SLINK AConnectionMode AUserConnLinkData (Maybe CRClientData) -- response LINK
   | JOIN Bool AConnectionRequestUri PQSupport SubscriptionMode ConnInfo
   | LET ConfirmationId ConnInfo -- ConnInfo is from client
   | ACK AgentMsgId (Maybe MsgReceiptInfo)
@@ -444,6 +446,7 @@ data ACommand
 
 data ACommandTag
   = NEW_
+  | SLINK_
   | JOIN_
   | LET_
   | ACK_
@@ -453,6 +456,7 @@ data ACommandTag
 
 data AEventTag (e :: AEntity) where
   INV_ :: AEventTag AEConn
+  LINK_ :: AEventTag AEConn
   CONF_ :: AEventTag AEConn
   REQ_ :: AEventTag AEConn
   INFO_ :: AEventTag AEConn
@@ -499,6 +503,7 @@ deriving instance Show (AEventTag e)
 aCommandTag :: ACommand -> ACommandTag
 aCommandTag = \case
   NEW {} -> NEW_
+  SLINK {} -> SLINK_
   JOIN {} -> JOIN_
   LET {} -> LET_
   ACK {} -> ACK_
@@ -508,6 +513,7 @@ aCommandTag = \case
 aEventTag :: AEvent e -> AEventTag e
 aEventTag = \case
   INV {} -> INV_
+  LINK _ -> LINK_
   CONF {} -> CONF_
   REQ {} -> REQ_
   INFO {} -> INFO_
@@ -1712,6 +1718,8 @@ data UserConnLinkData c where
   UserInvLinkData :: UserLinkData -> UserConnLinkData 'CMInvitation
   UserContactLinkData :: UserContactData -> UserConnLinkData 'CMContact
 
+data AUserConnLinkData = forall m. ConnectionModeI m => AUCLD (SConnectionMode m) (UserConnLinkData m)
+
 linkUserData :: ConnLinkData c -> UserLinkData
 linkUserData = \case
   InvitationLinkData _ d -> d
@@ -1777,6 +1785,10 @@ instance Encoding AConnLinkData where
         let cd = UserContactData {direct, owners, relays, userData}
         pure $ ACLD SCMContact $ ContactLinkData vr cd
 
+instance Encoding AUserConnLinkData where
+  smpEncode = undefined
+  smpP = undefined
+
 instance Encoding UserLinkData where
   smpEncode (UserLinkData s) = if B.length s <= 254 then smpEncode s else smpEncode ('\255', Large s)
   {-# INLINE smpEncode #-}
@@ -1976,6 +1988,7 @@ instance StrEncoding ACommandTag where
   strP =
     A.takeTill (== ' ') >>= \case
       "NEW" -> pure NEW_
+      "SLINK" -> pure SLINK_
       "JOIN" -> pure JOIN_
       "LET" -> pure LET_
       "ACK" -> pure ACK_
@@ -1984,6 +1997,7 @@ instance StrEncoding ACommandTag where
       _ -> fail "bad ACommandTag"
   strEncode = \case
     NEW_ -> "NEW"
+    SLINK_ -> "SLINK"
     JOIN_ -> "JOIN"
     LET_ -> "LET"
     ACK_ -> "ACK"
@@ -1995,6 +2009,7 @@ commandP binaryP =
   strP
     >>= \case
       NEW_ -> s (NEW <$> strP_ <*> strP_ <*> pqIKP <*> (strP <|> pure SMP.SMSubscribe))
+      SLINK_ -> undefined
       JOIN_ -> s (JOIN <$> strP_ <*> strP_ <*> pqSupP <*> (strP_ <|> pure SMP.SMSubscribe) <*> binaryP)
       LET_ -> s (LET <$> A.takeTill (== ' ') <* A.space <*> binaryP)
       ACK_ -> s (ACK <$> A.decimal <*> optional (A.space *> binaryP))
@@ -2012,6 +2027,7 @@ commandP binaryP =
 serializeCommand :: ACommand -> ByteString
 serializeCommand = \case
   NEW ntfs cMode pqIK subMode -> s (NEW_, ntfs, cMode, pqIK, subMode)
+  SLINK {} -> undefined
   JOIN ntfs cReq pqSup subMode cInfo -> s (JOIN_, ntfs, cReq, pqSup, subMode, Str $ serializeBinary cInfo)
   LET confId cInfo -> B.unwords [s LET_, confId, serializeBinary cInfo]
   ACK mId rcptInfo_ -> s (ACK_, mId) <> maybe "" (B.cons ' ' . serializeBinary) rcptInfo_

From eca591123f94159131fba699be1a5345dafe9729 Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Fri, 19 Dec 2025 13:30:54 +0400
Subject: [PATCH 2/7] rename

---
 src/Simplex/Messaging/Agent.hs          |  6 +++---
 src/Simplex/Messaging/Agent/Protocol.hs | 14 +++++++-------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/Simplex/Messaging/Agent.hs b/src/Simplex/Messaging/Agent.hs
index a10868653..66ac7893b 100644
--- a/src/Simplex/Messaging/Agent.hs
+++ b/src/Simplex/Messaging/Agent.hs
@@ -346,7 +346,7 @@ createConnectionAsync :: ConnectionModeI c => AgentClient -> UserId -> ACorrId -
 createConnectionAsync c userId aCorrId enableNtfs = withAgentEnv c .:. newConnAsync c userId aCorrId enableNtfs
 {-# INLINE createConnectionAsync #-}
 
--- | Create or update user's contact connection short link asynchronously, synchronous response is the short link
+-- | Create or update user's contact connection short link (LSET command) asynchronously, no synchronous response
 setConnShortLinkAsync :: AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AE ()
 setConnShortLinkAsync c = withAgentEnv c .::. setConnShortLinkAsync' c
 {-# INLINE setConnShortLinkAsync #-}
@@ -894,7 +894,7 @@ checkClientNotices AgentClient {clientNotices, presetServers} (ProtoServerWithAu
 
 setConnShortLinkAsync' :: AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AM ()
 setConnShortLinkAsync' c corrId connId cMode userLinkData clientData =
-  -- enqueue command SLINK
+  -- enqueue command LSET
   undefined
 
 setConnShortLink' :: AgentClient -> NetworkRequestMode -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AM (ConnShortLink c)
@@ -1668,7 +1668,7 @@ runCommandProcessing c@AgentClient {subQ} connId server_ Worker {doWork} = do
           tryCommand . withNextSrv c userId storageSrvs triedHosts [] $ \srv -> do
             (CCLink cReq _, service) <- newRcvConnSrv c NRMBackground userId connId enableNtfs cMode Nothing Nothing pqEnc subMode srv
             notify $ INV (ACR cMode cReq) service
-        SLINK {} ->
+        LSET {} ->
           -- create link (reuse setConnShortLink')
           -- notify - LINK
           undefined
diff --git a/src/Simplex/Messaging/Agent/Protocol.hs b/src/Simplex/Messaging/Agent/Protocol.hs
index 4946fd8b0..525ebfeb2 100644
--- a/src/Simplex/Messaging/Agent/Protocol.hs
+++ b/src/Simplex/Messaging/Agent/Protocol.hs
@@ -436,7 +436,7 @@ deriving instance Show AEvtTag
 
 data ACommand
   = NEW Bool AConnectionMode InitialKeys SubscriptionMode -- response INV
-  | SLINK AConnectionMode AUserConnLinkData (Maybe CRClientData) -- response LINK
+  | LSET AConnectionMode AUserConnLinkData (Maybe CRClientData) -- response LINK
   | JOIN Bool AConnectionRequestUri PQSupport SubscriptionMode ConnInfo
   | LET ConfirmationId ConnInfo -- ConnInfo is from client
   | ACK AgentMsgId (Maybe MsgReceiptInfo)
@@ -446,7 +446,7 @@ data ACommand
 
 data ACommandTag
   = NEW_
-  | SLINK_
+  | LSET_
   | JOIN_
   | LET_
   | ACK_
@@ -503,7 +503,7 @@ deriving instance Show (AEventTag e)
 aCommandTag :: ACommand -> ACommandTag
 aCommandTag = \case
   NEW {} -> NEW_
-  SLINK {} -> SLINK_
+  LSET {} -> LSET_
   JOIN {} -> JOIN_
   LET {} -> LET_
   ACK {} -> ACK_
@@ -1988,7 +1988,7 @@ instance StrEncoding ACommandTag where
   strP =
     A.takeTill (== ' ') >>= \case
       "NEW" -> pure NEW_
-      "SLINK" -> pure SLINK_
+      "LSET" -> pure LSET_
       "JOIN" -> pure JOIN_
       "LET" -> pure LET_
       "ACK" -> pure ACK_
@@ -1997,7 +1997,7 @@ instance StrEncoding ACommandTag where
       _ -> fail "bad ACommandTag"
   strEncode = \case
     NEW_ -> "NEW"
-    SLINK_ -> "SLINK"
+    LSET_ -> "LSET"
     JOIN_ -> "JOIN"
     LET_ -> "LET"
     ACK_ -> "ACK"
@@ -2009,7 +2009,7 @@ commandP binaryP =
   strP
     >>= \case
       NEW_ -> s (NEW <$> strP_ <*> strP_ <*> pqIKP <*> (strP <|> pure SMP.SMSubscribe))
-      SLINK_ -> undefined
+      LSET_ -> undefined
       JOIN_ -> s (JOIN <$> strP_ <*> strP_ <*> pqSupP <*> (strP_ <|> pure SMP.SMSubscribe) <*> binaryP)
       LET_ -> s (LET <$> A.takeTill (== ' ') <* A.space <*> binaryP)
       ACK_ -> s (ACK <$> A.decimal <*> optional (A.space *> binaryP))
@@ -2027,7 +2027,7 @@ commandP binaryP =
 serializeCommand :: ACommand -> ByteString
 serializeCommand = \case
   NEW ntfs cMode pqIK subMode -> s (NEW_, ntfs, cMode, pqIK, subMode)
-  SLINK {} -> undefined
+  LSET {} -> undefined
   JOIN ntfs cReq pqSup subMode cInfo -> s (JOIN_, ntfs, cReq, pqSup, subMode, Str $ serializeBinary cInfo)
   LET confId cInfo -> B.unwords [s LET_, confId, serializeBinary cInfo]
   ACK mId rcptInfo_ -> s (ACK_, mId) <> maybe "" (B.cons ' ' . serializeBinary) rcptInfo_

From f736b02cb7a2d356e43f90633f7fb0008d44161d Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Fri, 19 Dec 2025 17:30:39 +0400
Subject: [PATCH 3/7] wip

---
 src/Simplex/Messaging/Agent.hs          | 21 ++++++----
 src/Simplex/Messaging/Agent/Protocol.hs | 51 ++++++++++++++++++++++---
 tests/AgentTests/EqInstances.hs         | 14 +------
 tests/AgentTests/FunctionalAPITests.hs  |  5 ++-
 4 files changed, 64 insertions(+), 27 deletions(-)

diff --git a/src/Simplex/Messaging/Agent.hs b/src/Simplex/Messaging/Agent.hs
index 66ac7893b..ae09312dd 100644
--- a/src/Simplex/Messaging/Agent.hs
+++ b/src/Simplex/Messaging/Agent.hs
@@ -347,7 +347,7 @@ createConnectionAsync c userId aCorrId enableNtfs = withAgentEnv c .:. newConnAs
 {-# INLINE createConnectionAsync #-}
 
 -- | Create or update user's contact connection short link (LSET command) asynchronously, no synchronous response
-setConnShortLinkAsync :: AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AE ()
+setConnShortLinkAsync :: ConnectionModeI c => AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AE ()
 setConnShortLinkAsync c = withAgentEnv c .::. setConnShortLinkAsync' c
 {-# INLINE setConnShortLinkAsync #-}
 
@@ -892,10 +892,15 @@ checkClientNotices AgentClient {clientNotices, presetServers} (ProtoServerWithAu
         when (maybe True (ts <) expires_) $
           throwError NOTICE {server = safeDecodeUtf8 $ strEncode $ L.head host, preset = isNothing srvKey, expiresAt = roundedToUTCTime <$> expires_}
 
-setConnShortLinkAsync' :: AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AM ()
+setConnShortLinkAsync' :: forall c. ConnectionModeI c => AgentClient -> ACorrId -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AM ()
 setConnShortLinkAsync' c corrId connId cMode userLinkData clientData =
-  -- enqueue command LSET
-  undefined
+  withConnLock c connId "setConnShortLinkAsync" $ do
+    SomeConn _ conn <- withStore c (`getConn` connId)
+    srv <- case (conn, cMode, userLinkData) of
+      (ContactConnection _ RcvQueue {server}, SCMContact, UserContactLinkData {}) -> pure server
+      (RcvConnection _ RcvQueue {server}, SCMInvitation, UserInvLinkData {}) -> pure server
+      _ -> throwE $ CMD PROHIBITED "setConnShortLinkAsync: invalid connection or mode"
+    enqueueCommand c corrId connId (Just srv) $ AClientCommand $ LSET (AUCLD cMode userLinkData) clientData
 
 setConnShortLink' :: AgentClient -> NetworkRequestMode -> ConnId -> SConnectionMode c -> UserConnLinkData c -> Maybe CRClientData -> AM (ConnShortLink c)
 setConnShortLink' c nm connId cMode userLinkData clientData =
@@ -1668,10 +1673,10 @@ runCommandProcessing c@AgentClient {subQ} connId server_ Worker {doWork} = do
           tryCommand . withNextSrv c userId storageSrvs triedHosts [] $ \srv -> do
             (CCLink cReq _, service) <- newRcvConnSrv c NRMBackground userId connId enableNtfs cMode Nothing Nothing pqEnc subMode srv
             notify $ INV (ACR cMode cReq) service
-        LSET {} ->
-          -- create link (reuse setConnShortLink')
-          -- notify - LINK
-          undefined
+        LSET (AUCLD cMode userLinkData) clientData ->
+          withServer' . tryCommand $ do
+            link <- setConnShortLink' c NRMBackground connId cMode userLinkData clientData
+            notify $ LINK (ACSL cMode link)
         JOIN enableNtfs (ACR _ cReq@(CRInvitationUri ConnReqUriData {crSmpQueues = q :| _} _)) pqEnc subMode connInfo -> noServer $ do
           triedHosts <- newTVarIO S.empty
           tryCommand . withNextSrv c userId storageSrvs triedHosts [qServer q] $ \srv -> do
diff --git a/src/Simplex/Messaging/Agent/Protocol.hs b/src/Simplex/Messaging/Agent/Protocol.hs
index 525ebfeb2..080ea393a 100644
--- a/src/Simplex/Messaging/Agent/Protocol.hs
+++ b/src/Simplex/Messaging/Agent/Protocol.hs
@@ -112,6 +112,7 @@ module Simplex.Messaging.Agent.Protocol
     ServiceScheme,
     FixedLinkData (..),
     ConnLinkData (..),
+    AUserConnLinkData (..),
     UserConnLinkData (..),
     UserContactData (..),
     UserLinkData (..),
@@ -436,7 +437,7 @@ deriving instance Show AEvtTag
 
 data ACommand
   = NEW Bool AConnectionMode InitialKeys SubscriptionMode -- response INV
-  | LSET AConnectionMode AUserConnLinkData (Maybe CRClientData) -- response LINK
+  | LSET AUserConnLinkData (Maybe CRClientData) -- response LINK
   | JOIN Bool AConnectionRequestUri PQSupport SubscriptionMode ConnInfo
   | LET ConfirmationId ConnInfo -- ConnInfo is from client
   | ACK AgentMsgId (Maybe MsgReceiptInfo)
@@ -1709,8 +1710,10 @@ data UserContactData = UserContactData
     relays :: [ConnShortLink 'CMContact],
     userData :: UserLinkData
   }
+  deriving (Eq, Show)
 
 newtype UserLinkData = UserLinkData ByteString
+  deriving (Eq, Show)
 
 data AConnLinkData = forall m. ConnectionModeI m => ACLD (SConnectionMode m) (ConnLinkData m)
 
@@ -1718,8 +1721,19 @@ data UserConnLinkData c where
   UserInvLinkData :: UserLinkData -> UserConnLinkData 'CMInvitation
   UserContactLinkData :: UserContactData -> UserConnLinkData 'CMContact
 
+deriving instance Eq (UserConnLinkData m)
+
+deriving instance Show (UserConnLinkData m)
+
 data AUserConnLinkData = forall m. ConnectionModeI m => AUCLD (SConnectionMode m) (UserConnLinkData m)
 
+instance Eq AUserConnLinkData where
+  AUCLD m d == AUCLD m' d' = case testEquality m m' of
+    Just Refl -> d == d'
+    Nothing -> False
+
+deriving instance Show AUserConnLinkData
+
 linkUserData :: ConnLinkData c -> UserLinkData
 linkUserData = \case
   InvitationLinkData _ d -> d
@@ -1746,6 +1760,7 @@ data OwnerAuth = OwnerAuth
     -- Owner validation should detect and reject loops.
     authOwnerSig :: C.Signature 'C.Ed25519
   }
+  deriving (Eq, Show)
 
 instance Encoding OwnerAuth where
   smpEncode OwnerAuth {ownerId, ownerKey, ownerSig, authOwnerId, authOwnerSig} =
@@ -1785,9 +1800,35 @@ instance Encoding AConnLinkData where
         let cd = UserContactData {direct, owners, relays, userData}
         pure $ ACLD SCMContact $ ContactLinkData vr cd
 
+instance ConnectionModeI c => Encoding (UserConnLinkData c) where
+  smpEncode = \case
+    UserInvLinkData userData -> smpEncode (CMInvitation, userData)
+    UserContactLinkData UserContactData {direct, owners, relays, userData} ->
+      B.concat [smpEncode (CMContact, direct), smpEncodeList owners, smpEncodeList relays, smpEncode userData]
+  smpP = (\(AUCLD _ d) -> checkConnMode d) <$?> smpP
+  {-# INLINE smpP #-}
+
 instance Encoding AUserConnLinkData where
-  smpEncode = undefined
-  smpP = undefined
+  smpEncode (AUCLD _ d) = smpEncode d
+  {-# INLINE smpEncode #-}
+  smpP =
+    smpP >>= \case
+      CMInvitation -> do
+        userData <- smpP <* A.takeByteString -- ignoring tail for forward compatibility with the future link data encoding
+        pure $ AUCLD SCMInvitation $ UserInvLinkData userData
+      CMContact -> do
+        direct <- smpP
+        owners <- smpListP
+        relays <- smpListP
+        userData <- smpP <* A.takeByteString -- ignoring tail for forward compatibility with the future link data encoding
+        let cd = UserContactData {direct, owners, relays, userData}
+        pure $ AUCLD SCMContact $ UserContactLinkData cd
+
+instance StrEncoding AUserConnLinkData where
+  strEncode = smpEncode
+  {-# INLINE strEncode #-}
+  strP = smpP
+  {-# INLINE strP #-}
 
 instance Encoding UserLinkData where
   smpEncode (UserLinkData s) = if B.length s <= 254 then smpEncode s else smpEncode ('\255', Large s)
@@ -2009,7 +2050,7 @@ commandP binaryP =
   strP
     >>= \case
       NEW_ -> s (NEW <$> strP_ <*> strP_ <*> pqIKP <*> (strP <|> pure SMP.SMSubscribe))
-      LSET_ -> undefined
+      LSET_ -> s (LSET <$> strP <*> optional (A.space *> strP))
       JOIN_ -> s (JOIN <$> strP_ <*> strP_ <*> pqSupP <*> (strP_ <|> pure SMP.SMSubscribe) <*> binaryP)
       LET_ -> s (LET <$> A.takeTill (== ' ') <* A.space <*> binaryP)
       ACK_ -> s (ACK <$> A.decimal <*> optional (A.space *> binaryP))
@@ -2027,7 +2068,7 @@ commandP binaryP =
 serializeCommand :: ACommand -> ByteString
 serializeCommand = \case
   NEW ntfs cMode pqIK subMode -> s (NEW_, ntfs, cMode, pqIK, subMode)
-  LSET {} -> undefined
+  LSET uld cd_ -> s (LSET_, uld) <> maybe "" (B.cons ' ' . s) cd_
   JOIN ntfs cReq pqSup subMode cInfo -> s (JOIN_, ntfs, cReq, pqSup, subMode, Str $ serializeBinary cInfo)
   LET confId cInfo -> B.unwords [s LET_, confId, serializeBinary cInfo]
   ACK mId rcptInfo_ -> s (ACK_, mId) <> maybe "" (B.cons ' ' . serializeBinary) rcptInfo_
diff --git a/tests/AgentTests/EqInstances.hs b/tests/AgentTests/EqInstances.hs
index 63c493861..817580723 100644
--- a/tests/AgentTests/EqInstances.hs
+++ b/tests/AgentTests/EqInstances.hs
@@ -5,7 +5,7 @@
 module AgentTests.EqInstances where
 
 import Data.Type.Equality
-import Simplex.Messaging.Agent.Protocol (ConnLinkData (..), OwnerAuth (..), UserContactData (..), UserLinkData (..))
+import Simplex.Messaging.Agent.Protocol (ConnLinkData (..))
 import Simplex.Messaging.Agent.Store
 import Simplex.Messaging.Client (ProxiedRelay (..))
 
@@ -32,18 +32,6 @@ deriving instance Show (ConnLinkData c)
 
 deriving instance Eq (ConnLinkData c)
 
-deriving instance Show UserContactData
-
-deriving instance Eq UserContactData
-
-deriving instance Show UserLinkData
-
-deriving instance Eq UserLinkData
-
-deriving instance Show OwnerAuth
-
-deriving instance Eq OwnerAuth
-
 deriving instance Show ProxiedRelay
 
 deriving instance Eq ProxiedRelay
diff --git a/tests/AgentTests/FunctionalAPITests.hs b/tests/AgentTests/FunctionalAPITests.hs
index 1ceb675ab..e2e439fba 100644
--- a/tests/AgentTests/FunctionalAPITests.hs
+++ b/tests/AgentTests/FunctionalAPITests.hs
@@ -450,7 +450,7 @@ functionalAPITests ps = do
     it "should send multiple messages to the same connection" $ withSmpServer ps testSendMessagesB
     it "should send messages to the 2 connections" $ withSmpServer ps testSendMessagesB2
   describe "Async agent commands" $ do
-    describe "connect using async agent commands" $
+    fdescribe "connect using async agent commands" $
       testBasicMatrix2 ps testAsyncCommands
     it "should restore and complete async commands on restart" $
       testAsyncCommandsRestore ps
@@ -2583,6 +2583,9 @@ testAsyncCommands sqSecured alice bob baseId =
     bobId <- createConnectionAsync alice 1 "1" True SCMInvitation IKPQOn SMSubscribe
     ("1", bobId', INV (ACR _ qInfo)) <- get alice
     liftIO $ bobId' `shouldBe` bobId
+    setConnShortLinkAsync alice "1a" bobId SCMInvitation (UserInvLinkData $ UserLinkData "test") Nothing
+    ("1a", bobId'', LINK (ACSL SCMInvitation _)) <- get alice
+    liftIO $ bobId'' `shouldBe` bobId
     aliceId <- joinConnectionAsync bob 1 "2" True qInfo "bob's connInfo" PQSupportOn SMSubscribe
     ("2", aliceId', JOINED sqSecured') <- get bob
     liftIO $ do

From c047df4273748e1706eccc4e7c0923a7c2a29b4a Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Fri, 19 Dec 2025 17:43:47 +0400
Subject: [PATCH 4/7] test

---
 tests/AgentTests/FunctionalAPITests.hs | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/tests/AgentTests/FunctionalAPITests.hs b/tests/AgentTests/FunctionalAPITests.hs
index e2e439fba..9e42b8798 100644
--- a/tests/AgentTests/FunctionalAPITests.hs
+++ b/tests/AgentTests/FunctionalAPITests.hs
@@ -450,8 +450,10 @@ functionalAPITests ps = do
     it "should send multiple messages to the same connection" $ withSmpServer ps testSendMessagesB
     it "should send messages to the 2 connections" $ withSmpServer ps testSendMessagesB2
   describe "Async agent commands" $ do
-    fdescribe "connect using async agent commands" $
+    describe "connect using async agent commands" $
       testBasicMatrix2 ps testAsyncCommands
+    fit "should add short link data using async agent command" $
+      testSetConnShortLinkAsync ps
     it "should restore and complete async commands on restart" $
       testAsyncCommandsRestore ps
     describe "accept connection using async command" $
@@ -2583,9 +2585,6 @@ testAsyncCommands sqSecured alice bob baseId =
     bobId <- createConnectionAsync alice 1 "1" True SCMInvitation IKPQOn SMSubscribe
     ("1", bobId', INV (ACR _ qInfo)) <- get alice
     liftIO $ bobId' `shouldBe` bobId
-    setConnShortLinkAsync alice "1a" bobId SCMInvitation (UserInvLinkData $ UserLinkData "test") Nothing
-    ("1a", bobId'', LINK (ACSL SCMInvitation _)) <- get alice
-    liftIO $ bobId'' `shouldBe` bobId
     aliceId <- joinConnectionAsync bob 1 "2" True qInfo "bob's connInfo" PQSupportOn SMSubscribe
     ("2", aliceId', JOINED sqSecured') <- get bob
     liftIO $ do
@@ -2631,6 +2630,23 @@ testAsyncCommands sqSecured alice bob baseId =
   where
     msgId = subtract baseId
 
+testSetConnShortLinkAsync :: (ASrvTransport, AStoreType) -> IO ()
+testSetConnShortLinkAsync ps = withAgentClients2 $ \alice bob ->
+  withSmpServerStoreLogOn ps testPort $ \_ -> runRight_ $ do
+    let userData = UserLinkData "test user data"
+        newLinkData = UserInvLinkData userData
+    (bobId, (CCLink qInfo _, _)) <- A.createConnection alice NRMInteractive 1 True True SCMInvitation (Just newLinkData) Nothing IKPQOn SMSubscribe
+    let updatedData = UserLinkData "updated user data"
+    setConnShortLinkAsync alice "1" bobId SCMInvitation (UserInvLinkData updatedData) Nothing
+    ("1", bobId', LINK (ACSL SCMInvitation _)) <- get alice
+    liftIO $ bobId' `shouldBe` bobId
+    (aliceId, _) <- joinConnection bob 1 True qInfo "bob's connInfo" SMSubscribe
+    ("", _, CONF confId _ "bob's connInfo") <- get alice
+    allowConnection alice bobId confId "alice's connInfo"
+    get alice ##> ("", bobId, CON)
+    get bob ##> ("", aliceId, INFO "alice's connInfo")
+    get bob ##> ("", aliceId, CON)
+
 testAsyncCommandsRestore :: (ASrvTransport, AStoreType) -> IO ()
 testAsyncCommandsRestore ps = do
   alice <- getSMPAgentClient' 1 agentCfg initAgentServers testDB

From 1c204a5430aedaeee6ceaf152a28e2df04d8b448 Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Fri, 19 Dec 2025 18:02:21 +0400
Subject: [PATCH 5/7] better test

---
 tests/AgentTests/FunctionalAPITests.hs | 29 +++++++++++++++++++-------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/tests/AgentTests/FunctionalAPITests.hs b/tests/AgentTests/FunctionalAPITests.hs
index 9e42b8798..97dec4472 100644
--- a/tests/AgentTests/FunctionalAPITests.hs
+++ b/tests/AgentTests/FunctionalAPITests.hs
@@ -2634,17 +2634,30 @@ testSetConnShortLinkAsync :: (ASrvTransport, AStoreType) -> IO ()
 testSetConnShortLinkAsync ps = withAgentClients2 $ \alice bob ->
   withSmpServerStoreLogOn ps testPort $ \_ -> runRight_ $ do
     let userData = UserLinkData "test user data"
-        newLinkData = UserInvLinkData userData
-    (bobId, (CCLink qInfo _, _)) <- A.createConnection alice NRMInteractive 1 True True SCMInvitation (Just newLinkData) Nothing IKPQOn SMSubscribe
+        userCtData = UserContactData {direct = True, owners = [], relays = [], userData}
+        newLinkData = UserContactLinkData userCtData
+    (contactId, (CCLink qInfo (Just shortLink), _)) <- A.createConnection alice NRMInteractive 1 True True SCMContact (Just newLinkData) Nothing IKPQOn SMSubscribe
+    -- verify initial link data
+    (_, ContactLinkData _ userCtData') <- getConnShortLink bob 1 shortLink
+    liftIO $ userCtData' `shouldBe` userCtData
+    -- update link data async
     let updatedData = UserLinkData "updated user data"
-    setConnShortLinkAsync alice "1" bobId SCMInvitation (UserInvLinkData updatedData) Nothing
-    ("1", bobId', LINK (ACSL SCMInvitation _)) <- get alice
-    liftIO $ bobId' `shouldBe` bobId
+        updatedCtData = UserContactData {direct = False, owners = [], relays = [], userData = updatedData}
+    setConnShortLinkAsync alice "1" contactId SCMContact (UserContactLinkData updatedCtData) Nothing
+    ("1", contactId', LINK (ACSL SCMContact _)) <- get alice
+    liftIO $ contactId' `shouldBe` contactId
+    -- verify updated link data
+    (_, ContactLinkData _ updatedCtData') <- getConnShortLink bob 1 shortLink
+    liftIO $ updatedCtData' `shouldBe` updatedCtData
+    -- complete connection via contact address
     (aliceId, _) <- joinConnection bob 1 True qInfo "bob's connInfo" SMSubscribe
-    ("", _, CONF confId _ "bob's connInfo") <- get alice
-    allowConnection alice bobId confId "alice's connInfo"
+    ("", _, REQ invId _ "bob's connInfo") <- get alice
+    bobId <- A.prepareConnectionToAccept alice 1 True invId PQSupportOn
+    (_, Nothing) <- acceptContact alice 1 bobId True invId "alice's connInfo" PQSupportOn SMSubscribe
+    ("", _, CONF confId _ "alice's connInfo") <- get bob
+    allowConnection bob aliceId confId "bob's connInfo"
+    get alice ##> ("", bobId, INFO "bob's connInfo")
     get alice ##> ("", bobId, CON)
-    get bob ##> ("", aliceId, INFO "alice's connInfo")
     get bob ##> ("", aliceId, CON)
 
 testAsyncCommandsRestore :: (ASrvTransport, AStoreType) -> IO ()

From 92ee3cdbf40b1aee3bc399147af2308da9acc1d0 Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Fri, 19 Dec 2025 19:30:54 +0400
Subject: [PATCH 6/7] enable tests

---
 tests/AgentTests/FunctionalAPITests.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/AgentTests/FunctionalAPITests.hs b/tests/AgentTests/FunctionalAPITests.hs
index 97dec4472..92756f3d0 100644
--- a/tests/AgentTests/FunctionalAPITests.hs
+++ b/tests/AgentTests/FunctionalAPITests.hs
@@ -452,7 +452,7 @@ functionalAPITests ps = do
   describe "Async agent commands" $ do
     describe "connect using async agent commands" $
       testBasicMatrix2 ps testAsyncCommands
-    fit "should add short link data using async agent command" $
+    it "should add short link data using async agent command" $
       testSetConnShortLinkAsync ps
     it "should restore and complete async commands on restart" $
       testAsyncCommandsRestore ps

From 7782228093932a1e8d45801d24f6b224d9229ab8 Mon Sep 17 00:00:00 2001
From: spaced4ndy <8711996+spaced4ndy@users.noreply.github.com>
Date: Fri, 19 Dec 2025 19:41:00 +0400
Subject: [PATCH 7/7] add to test

---
 tests/AgentTests/FunctionalAPITests.hs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/tests/AgentTests/FunctionalAPITests.hs b/tests/AgentTests/FunctionalAPITests.hs
index 92756f3d0..5647550a9 100644
--- a/tests/AgentTests/FunctionalAPITests.hs
+++ b/tests/AgentTests/FunctionalAPITests.hs
@@ -2636,18 +2636,19 @@ testSetConnShortLinkAsync ps = withAgentClients2 $ \alice bob ->
     let userData = UserLinkData "test user data"
         userCtData = UserContactData {direct = True, owners = [], relays = [], userData}
         newLinkData = UserContactLinkData userCtData
-    (contactId, (CCLink qInfo (Just shortLink), _)) <- A.createConnection alice NRMInteractive 1 True True SCMContact (Just newLinkData) Nothing IKPQOn SMSubscribe
+    (cId, (CCLink qInfo (Just shortLink), _)) <- A.createConnection alice NRMInteractive 1 True True SCMContact (Just newLinkData) Nothing IKPQOn SMSubscribe
     -- verify initial link data
     (_, ContactLinkData _ userCtData') <- getConnShortLink bob 1 shortLink
     liftIO $ userCtData' `shouldBe` userCtData
     -- update link data async
     let updatedData = UserLinkData "updated user data"
         updatedCtData = UserContactData {direct = False, owners = [], relays = [], userData = updatedData}
-    setConnShortLinkAsync alice "1" contactId SCMContact (UserContactLinkData updatedCtData) Nothing
-    ("1", contactId', LINK (ACSL SCMContact _)) <- get alice
-    liftIO $ contactId' `shouldBe` contactId
+    setConnShortLinkAsync alice "1" cId SCMContact (UserContactLinkData updatedCtData) Nothing
+    ("1", cId', LINK (ACSL SCMContact shortLink')) <- get alice
+    liftIO $ cId' `shouldBe` cId
+    liftIO $ shortLink' `shouldBe` shortLink
     -- verify updated link data
-    (_, ContactLinkData _ updatedCtData') <- getConnShortLink bob 1 shortLink
+    (_, ContactLinkData _ updatedCtData') <- getConnShortLink bob 1 shortLink'
     liftIO $ updatedCtData' `shouldBe` updatedCtData
     -- complete connection via contact address
     (aliceId, _) <- joinConnection bob 1 True qInfo "bob's connInfo" SMSubscribe