diff --git a/libp2p/protocols/pubsub/gossipsub/scoring.nim b/libp2p/protocols/pubsub/gossipsub/scoring.nim
index d2db2c20b..3c82d5671 100644
--- a/libp2p/protocols/pubsub/gossipsub/scoring.nim
+++ b/libp2p/protocols/pubsub/gossipsub/scoring.nim
@@ -71,9 +71,9 @@ proc disconnectPeer(g: GossipSub, peer: PubSubPeer) {.async.} =
           peer.shortAgent
         else:
           if peer.sendConn != nil:
-            let shortAgent = peer.sendConn.peerInfo.agentVersion.split("/")[0].toLowerAscii()
-            if KnownLibP2PAgentsSeq.contains(shortAgent):
-              peer.shortAgent = shortAgent
+            let shortAgent = peer.sendConn.peerInfo.agentVersion.split("/")[0].safeToLowerAscii()
+            if shortAgent.isOk() and KnownLibP2PAgentsSeq.contains(shortAgent.get()):
+              peer.shortAgent = shortAgent.get()
             else:
               peer.shortAgent = "unknown"
             peer.shortAgent
@@ -165,9 +165,9 @@ proc updateScores*(g: GossipSub) = # avoid async
               peer.shortAgent
             else:
               if peer.sendConn != nil:
-                let shortAgent = peer.sendConn.peerInfo.agentVersion.split("/")[0].toLowerAscii()
-                if KnownLibP2PAgentsSeq.contains(shortAgent):
-                  peer.shortAgent = shortAgent
+                let shortAgent = peer.sendConn.peerInfo.agentVersion.split("/")[0].safeToLowerAscii()
+                if shortAgent.isOk() and KnownLibP2PAgentsSeq.contains(shortAgent.get()):
+                  peer.shortAgent = shortAgent.get()
                 else:
                   peer.shortAgent = "unknown"
                 peer.shortAgent
@@ -221,9 +221,9 @@ proc updateScores*(g: GossipSub) = # avoid async
             peer.shortAgent
           else:
             if peer.sendConn != nil:
-              let shortAgent = peer.sendConn.peerInfo.agentVersion.split("/")[0].toLowerAscii()
-              if KnownLibP2PAgentsSeq.contains(shortAgent):
-                peer.shortAgent = shortAgent
+              let shortAgent = peer.sendConn.peerInfo.agentVersion.split("/")[0].safeToLowerAscii()
+              if shortAgent.isOk() and KnownLibP2PAgentsSeq.contains(shortAgent.get()):
+                peer.shortAgent = shortAgent.get()
               else:
                 peer.shortAgent = "unknown"
               peer.shortAgent
diff --git a/libp2p/stream/chronosstream.nim b/libp2p/stream/chronosstream.nim
index 259587f92..bb8416b3e 100644
--- a/libp2p/stream/chronosstream.nim
+++ b/libp2p/stream/chronosstream.nim
@@ -79,9 +79,9 @@ when defined(libp2p_agents_metrics):
     if not s.tracked:
       if not isNil(s.peerInfo) and s.peerInfo.agentVersion.len > 0:
         # / seems a weak "standard" so for now it's reliable
-        let shortAgent = s.peerInfo.agentVersion.split("/")[0].toLowerAscii()
-        if KnownLibP2PAgentsSeq.contains(shortAgent):
-          s.shortAgent = shortAgent
+        let shortAgent = s.peerInfo.agentVersion.split("/")[0].safeToLowerAscii()
+        if shortAgent.isOk() and KnownLibP2PAgentsSeq.contains(shortAgent.get()):
+          s.shortAgent = shortAgent.get()
         else:
           s.shortAgent = "unknown"
         libp2p_peers_identity.inc(labelValues = [s.shortAgent])
diff --git a/libp2p/utility.nim b/libp2p/utility.nim
index f866e9ecb..11c427d6c 100644
--- a/libp2p/utility.nim
+++ b/libp2p/utility.nim
@@ -39,6 +39,18 @@ func shortLog*(item: string): string =
     result &= item[(item.len - split)..item.high]
 
 when defined(libp2p_agents_metrics):
+  import strutils
+  export split
+
+  import stew/results
+  export results
+
+  proc safeToLowerAscii*(s: string): Result[string, cstring] =
+    try:
+      ok(s.toLowerAscii())
+    except:
+      err("toLowerAscii failed")
+
   const
     KnownLibP2PAgents* {.strdefine.} = ""
-    KnownLibP2PAgentsSeq* = KnownLibP2PAgents.toLowerAscii().split(",")
+    KnownLibP2PAgentsSeq* = KnownLibP2PAgents.safeToLowerAscii().tryGet().split(",")