diff --git a/libp2p/protocols/connectivity/relay/client.nim b/libp2p/protocols/connectivity/relay/client.nim
index 8eeeeb0ee..601e29cd3 100644
--- a/libp2p/protocols/connectivity/relay/client.nim
+++ b/libp2p/protocols/connectivity/relay/client.nim
@@ -292,7 +292,9 @@ proc new*(T: typedesc[RelayClient], canHop: bool = false,
              maxCircuitPerPeer: maxCircuitPerPeer,
              msgSize: msgSize,
              isCircuitRelayV1: circuitRelayV1)
-  proc handleStream(conn: Connection, proto: string) {.async.} =
+  proc handleStream(
+      conn: Connection,
+      proto: string) {.async: (raises: [CancelledError]).} =
     try:
       case proto:
       of RelayV1Codec: await cl.handleStreamV1(conn)
diff --git a/libp2p/protocols/connectivity/relay/relay.nim b/libp2p/protocols/connectivity/relay/relay.nim
index b078cdb46..6c7c7bbd5 100644
--- a/libp2p/protocols/connectivity/relay/relay.nim
+++ b/libp2p/protocols/connectivity/relay/relay.nim
@@ -336,7 +336,9 @@ proc new*(T: typedesc[Relay],
             msgSize: msgSize,
             isCircuitRelayV1: circuitRelayV1)
 
-  proc handleStream(conn: Connection, proto: string) {.async.} =
+  proc handleStream(
+      conn: Connection,
+      proto: string) {.async: (raises: [CancelledError]).} =
     try:
       case proto:
       of RelayV2HopCodec: await r.handleHopStreamV2(conn)
diff --git a/libp2p/protocols/identify.nim b/libp2p/protocols/identify.nim
index 392eb9111..33621cd5e 100644
--- a/libp2p/protocols/identify.nim
+++ b/libp2p/protocols/identify.nim
@@ -1,5 +1,5 @@
 # Nim-LibP2P
-# Copyright (c) 2023 Status Research & Development GmbH
+# Copyright (c) 2023-2024 Status Research & Development GmbH
 # Licensed under either of
 #  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
 #  * MIT license ([LICENSE-MIT](LICENSE-MIT))
@@ -151,14 +151,16 @@ proc new*(
   identify
 
 method init*(p: Identify) =
-  proc handle(conn: Connection, proto: string) {.async.} =
+  proc handle(
+      conn: Connection,
+      proto: string) {.async: (raises: [CancelledError]).} =
     try:
       trace "handling identify request", conn
       var pb = encodeMsg(p.peerInfo, conn.observedAddr, p.sendSignedPeerRecord)
       await conn.writeLp(pb.buffer)
     except CancelledError as exc:
       raise exc
-    except CatchableError as exc:
+    except LPStreamError as exc:
       trace "exception in identify handler", exc = exc.msg, conn
     finally:
       trace "exiting identify handler", conn
@@ -207,7 +209,9 @@ proc new*(T: typedesc[IdentifyPush], handler: IdentifyPushHandler = nil): T {.pu
   identifypush
 
 proc init*(p: IdentifyPush) =
-  proc handle(conn: Connection, proto: string) {.async.} =
+  proc handle(
+      conn: Connection,
+      proto: string) {.async: (raises: [CancelledError]).} =
     trace "handling identify push", conn
     try:
       var message = await conn.readLp(64*1024)
diff --git a/libp2p/protocols/ping.nim b/libp2p/protocols/ping.nim
index 0921022b9..f7c36960a 100644
--- a/libp2p/protocols/ping.nim
+++ b/libp2p/protocols/ping.nim
@@ -36,10 +36,8 @@ type
   PingError* = object of LPError
   WrongPingAckError* = object of PingError
 
-  PingHandler* {.public.} = proc (
-    peer: PeerId):
-    Future[void]
-    {.gcsafe, raises: [].}
+  PingHandler* {.public.} =
+    proc (peer: PeerId): Future[void] {.async: (raises: []).}
 
   Ping* = ref object of LPProtocol
     pingHandler*: PingHandler
@@ -51,7 +49,9 @@ proc new*(T: typedesc[Ping], handler: PingHandler = nil, rng: ref HmacDrbgContex
   ping
 
 method init*(p: Ping) =
-  proc handle(conn: Connection, proto: string) {.async.} =
+  proc handle(
+      conn: Connection,
+      proto: string) {.async: (raises: [CancelledError]).} =
     try:
       trace "handling ping", conn
       var buf: array[PingSize, byte]
@@ -62,7 +62,7 @@ method init*(p: Ping) =
         await p.pingHandler(conn.peerId)
     except CancelledError as exc:
       raise exc
-    except CatchableError as exc:
+    except LPStreamError as exc:
       trace "exception in ping handler", exc = exc.msg, conn
 
   p.handler = handle
diff --git a/libp2p/protocols/protocol.nim b/libp2p/protocols/protocol.nim
index cb328849d..b9becb53f 100644
--- a/libp2p/protocols/protocol.nim
+++ b/libp2p/protocols/protocol.nim
@@ -1,5 +1,5 @@
 # Nim-LibP2P
-# Copyright (c) 2023 Status Research & Development GmbH
+# Copyright (c) 2023-2024 Status Research & Development GmbH
 # Licensed under either of
 #  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
 #  * MIT license ([LICENSE-MIT](LICENSE-MIT))
@@ -19,14 +19,13 @@ const
 
 type
   LPProtoHandler* = proc (
-    conn: Connection,
-    proto: string):
-    Future[void]
-    {.gcsafe, raises: [].}
+      conn: Connection,
+      proto: string
+  ): Future[void] {.async: (raises: [CancelledError]).}
 
   LPProtocol* = ref object of RootObj
     codecs*: seq[string]
-    handler*: LPProtoHandler ## this handler gets invoked by the protocol negotiator
+    handler*: LPProtoHandler ## gets invoked by the protocol negotiator
     started*: bool
     maxIncomingStreams: Opt[int]
 
@@ -50,10 +49,10 @@ func `codec=`*(p: LPProtocol, codec: string) =
   p.codecs.insert(codec, 0)
 
 proc new*(
-  T: type LPProtocol,
-  codecs: seq[string],
-  handler: LPProtoHandler,
-  maxIncomingStreams: Opt[int] | int = Opt.none(int)): T =
+    T: type LPProtocol,
+    codecs: seq[string],
+    handler: LPProtoHandler,
+    maxIncomingStreams: Opt[int] | int = Opt.none(int)): T =
   T(
     codecs: codecs,
     handler: handler,
diff --git a/libp2p/protocols/rendezvous.nim b/libp2p/protocols/rendezvous.nim
index 177116166..afd35b46e 100644
--- a/libp2p/protocols/rendezvous.nim
+++ b/libp2p/protocols/rendezvous.nim
@@ -641,7 +641,9 @@ proc new*(
     sema: newAsyncSemaphore(SemaphoreDefaultSize)
   )
   logScope: topics = "libp2p discovery rendezvous"
-  proc handleStream(conn: Connection, proto: string) {.async.} =
+  proc handleStream(
+      conn: Connection,
+      proto: string) {.async: (raises: [CancelledError]).} =
     try:
       let
         buf = await conn.readLp(4096)
diff --git a/libp2p/protocols/secure/secure.nim b/libp2p/protocols/secure/secure.nim
index eef56f7d8..e16e2bf5c 100644
--- a/libp2p/protocols/secure/secure.nim
+++ b/libp2p/protocols/secure/secure.nim
@@ -88,10 +88,12 @@ method handshake*(
     CancelledError, LPStreamError], raw: true), base.} =
   raiseAssert("Not implemented!")
 
-proc handleConn(s: Secure,
-                conn: Connection,
-                initiator: bool,
-                peerId: Opt[PeerId]): Future[Connection] {.async.} =
+proc handleConn(
+    s: Secure,
+    conn: Connection,
+    initiator: bool,
+    peerId: Opt[PeerId]
+): Future[Connection] {.async: (raises: [CancelledError, LPStreamError]).} =
   var sconn = await s.handshake(conn, initiator, peerId)
   # mark connection bottom level transport direction
   # this is the safest place to do this
@@ -115,14 +117,8 @@ proc handleConn(s: Secure,
           fut1 = sconn.close()
           fut2 = conn.close()
         await allFutures(fut1, fut2)
-        if fut1.failed:
-          let err = fut1.error()
-          if not (err of CancelledError):
-            debug "error cleaning up secure connection", err = err.msg, sconn
-        if fut2.failed:
-          let err = fut2.error()
-          if not (err of CancelledError):
-            debug "error cleaning up secure connection", err = err.msg, sconn
+        static: doAssert typeof(fut1).E is void  # Cannot fail
+        static: doAssert typeof(fut2).E is void  # Cannot fail
 
     except CancelledError:
       # This is top-level procedure which will work as separate task, so it
@@ -133,12 +129,14 @@ proc handleConn(s: Secure,
     # All the errors are handled inside `cleanup()` procedure.
     asyncSpawn cleanup()
 
-  return sconn
+  sconn
 
 method init*(s: Secure) =
   procCall LPProtocol(s).init()
 
-  proc handle(conn: Connection, proto: string) {.async.} =
+  proc handle(
+      conn: Connection,
+      proto: string) {.async: (raises: [CancelledError]).} =
     trace "handling connection upgrade", proto, conn
     try:
       # We don't need the result but we
@@ -149,16 +147,18 @@ method init*(s: Secure) =
       warn "securing connection canceled", conn
       await conn.close()
       raise exc
-    except CatchableError as exc:
+    except LPStreamError as exc:
       warn "securing connection failed", err = exc.msg, conn
       await conn.close()
 
   s.handler = handle
 
-method secure*(s: Secure,
-               conn: Connection,
-               peerId: Opt[PeerId]):
-               Future[Connection] {.base.} =
+method secure*(
+    s: Secure,
+    conn: Connection,
+    peerId: Opt[PeerId]
+): Future[Connection] {.async: (raises: [
+    CancelledError, LPStreamError], raw: true), base.} =
   s.handleConn(conn, conn.dir == Direction.Out, peerId)
 
 method readOnce*(