diff --git a/go.mod b/go.mod
index fa0fc11..aa6dbbe 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@ require (
 	golang.org/x/sync v0.5.0
 )
 
-require github.com/creachadair/mds v0.3.1
+require github.com/creachadair/mds v0.5.1
 
 go 1.21
 
diff --git a/go.sum b/go.sum
index 1699bfb..878f871 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,5 @@
-github.com/creachadair/mds v0.3.1 h1:pvHUjQUuQs/X8/BkN6vPAlWcNkTB1fdut8kmpoteSTY=
-github.com/creachadair/mds v0.3.1/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
+github.com/creachadair/mds v0.5.1 h1:x0CzsB0SGxrgWdRFPcBd6UnNxu5Azpc1/Beh5hgK2mo=
+github.com/creachadair/mds v0.5.1/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
 github.com/fortytw2/leaktest v1.3.0 h1:u8491cBMTQ8ft8aeV+adlcytMZylmA5nnwwkRZjI8vw=
 github.com/fortytw2/leaktest v1.3.0/go.mod h1:jDsjWgpAGjm2CA7WthBh/CdZYEPF31XHquHwclZch5g=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
diff --git a/tools/go.mod b/tools/go.mod
index 6330b8b..5700da3 100644
--- a/tools/go.mod
+++ b/tools/go.mod
@@ -6,11 +6,11 @@ toolchain go1.21.0
 
 require (
 	github.com/creachadair/jrpc2 v1.1.2
-	github.com/creachadair/wschannel v0.0.0-20231117144236-977d4aae64f7
+	github.com/creachadair/wschannel v0.0.0-20231211041550-f82e9bbfc258
 )
 
 require (
-	github.com/creachadair/mds v0.3.1 // indirect
+	github.com/creachadair/mds v0.5.1 // indirect
 	golang.org/x/sync v0.5.0 // indirect
 	nhooyr.io/websocket v1.8.10 // indirect
 )
diff --git a/tools/go.sum b/tools/go.sum
index 328b32b..e639a32 100644
--- a/tools/go.sum
+++ b/tools/go.sum
@@ -1,9 +1,9 @@
 github.com/creachadair/jrpc2 v1.1.2 h1:UOYMipEFYlwd5qmcvs9GZBurn3oXt1UDIX5JLjWWFzo=
 github.com/creachadair/jrpc2 v1.1.2/go.mod h1:JcCe2Eny3lIvVwZLm92WXyU+tNUgTBWFCLMsfNkjEGk=
-github.com/creachadair/mds v0.3.1 h1:pvHUjQUuQs/X8/BkN6vPAlWcNkTB1fdut8kmpoteSTY=
-github.com/creachadair/mds v0.3.1/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
-github.com/creachadair/wschannel v0.0.0-20231117144236-977d4aae64f7 h1:zzp1hsa6V3iuxfGWOTrCqMfNjXZ8OlZcHSbMMF+94tU=
-github.com/creachadair/wschannel v0.0.0-20231117144236-977d4aae64f7/go.mod h1:G2LDwAuE2B2YbCxMaxnB1qSC0Hzoy2Tf9eRel2qbRi8=
+github.com/creachadair/mds v0.5.1 h1:x0CzsB0SGxrgWdRFPcBd6UnNxu5Azpc1/Beh5hgK2mo=
+github.com/creachadair/mds v0.5.1/go.mod h1:4vrFYUzTXMJpMBU+OA292I6IUxKWCCfZkgXg+/kBZMo=
+github.com/creachadair/wschannel v0.0.0-20231211041550-f82e9bbfc258 h1:ylCT9u85Nxnsv6nSeye9CTWRtrzUm/nuwUMoVgW/VCw=
+github.com/creachadair/wschannel v0.0.0-20231211041550-f82e9bbfc258/go.mod h1:G2LDwAuE2B2YbCxMaxnB1qSC0Hzoy2Tf9eRel2qbRi8=
 github.com/fortytw2/leaktest v1.3.0 h1:u8491cBMTQ8ft8aeV+adlcytMZylmA5nnwwkRZjI8vw=
 github.com/fortytw2/leaktest v1.3.0/go.mod h1:jDsjWgpAGjm2CA7WthBh/CdZYEPF31XHquHwclZch5g=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=