diff --git a/plugins/commando.c b/plugins/commando.c
index 5803d79cb..8baaf999f 100644
--- a/plugins/commando.c
+++ b/plugins/commando.c
@@ -365,6 +365,7 @@ static void try_command(struct node_id *peer,
 	const jsmntok_t *toks, *method, *params, *rune, *id;
 	const char *buf = (const char *)msg, *failmsg;
 	struct out_req *req;
+	const char *cmdid_prefix;
 
 	incoming->peer = *peer;
 	incoming->id = idnum;
@@ -395,10 +396,17 @@ static void try_command(struct node_id *peer,
 	}
 	rune = json_get_member(buf, toks, "rune");
 	id = json_get_member(buf, toks, "id");
-	if (!id && !deprecated_apis) {
-		commando_error(incoming, COMMANDO_ERROR_REMOTE,
-			       "missing id field");
-		return;
+	if (!id) {
+		if (!deprecated_apis) {
+			commando_error(incoming, COMMANDO_ERROR_REMOTE,
+				       "missing id field");
+			return;
+		}
+		cmdid_prefix = NULL;
+	} else {
+		cmdid_prefix = tal_fmt(tmpctx, "%.*s/",
+				       id->end - id->start,
+				       buf + id->start);
 	}
 
 	failmsg = check_rune(tmpctx, incoming, peer, buf, method, params, rune);
@@ -412,6 +420,7 @@ static void try_command(struct node_id *peer,
 	req = jsonrpc_request_whole_object_start(plugin, NULL,
 						 json_strdup(tmpctx, buf,
 							     method),
+						 cmdid_prefix,
 						 cmd_done, incoming);
 	if (params) {
 		size_t i;
diff --git a/plugins/libplugin.c b/plugins/libplugin.c
index 9d78ccc85..ed9bd46c2 100644
--- a/plugins/libplugin.c
+++ b/plugins/libplugin.c
@@ -172,25 +172,30 @@ static void disable_request_cb(struct command *cmd, struct out_req *out)
 	out->cmd = NULL;
 }
 
-static const char *get_json_id(const tal_t *ctx,
-			       struct plugin *plugin,
-			       const char *cmd_id,
-			       const char *method)
+const char *json_id_prefix(const tal_t *ctx, const struct command *cmd)
 {
-	const char *prefix;
+	if (!cmd)
+		return "";
 
-	if (cmd_id) {
-		/* Strip quotes! */
-		if (strstarts(cmd_id, "\"")) {
-			assert(strlen(cmd_id) >= 2);
-			assert(strends(cmd_id, "\""));
-			prefix = tal_fmt(tmpctx, "%.*s/",
-					 (int)strlen(cmd_id) - 2, cmd_id + 1);
-		} else
-			prefix = tal_fmt(tmpctx, "%s/", cmd_id);
-	} else
-		prefix = "";
+	/* Notifications have no cmd->id, use methodname */
+	if (!cmd->id)
+		return tal_fmt(ctx, "%s/", cmd->methodname);
 
+	/* Strip quotes! */
+	if (strstarts(cmd->id, "\"")) {
+		assert(strlen(cmd->id) >= 2);
+		assert(strends(cmd->id, "\""));
+		return tal_fmt(ctx, "%.*s/",
+			       (int)strlen(cmd->id) - 2, cmd->id + 1);
+	}
+	return tal_fmt(ctx, "%s/", cmd->id);
+}
+
+static const char *append_json_id(const tal_t *ctx,
+				  struct plugin *plugin,
+				  const char *method,
+				  const char *prefix)
+{
 	return tal_fmt(ctx, "\"%s%s:%s#%"PRIu64"\"",
 		       prefix, plugin->id, method, plugin->next_outreq_id++);
 }
@@ -205,6 +210,7 @@ static void destroy_out_req(struct out_req *out_req, struct plugin *plugin)
 struct out_req *
 jsonrpc_request_start_(struct plugin *plugin, struct command *cmd,
 		       const char *method,
+		       const char *id_prefix,
 		       struct command_result *(*cb)(struct command *command,
 						    const char *buf,
 						    const jsmntok_t *result,
@@ -218,7 +224,7 @@ jsonrpc_request_start_(struct plugin *plugin, struct command *cmd,
 	struct out_req *out;
 
 	out = tal(cmd, struct out_req);
-	out->id = get_json_id(out, plugin, cmd ? cmd->id : NULL, method);
+	out->id = append_json_id(out, plugin, method, id_prefix);
 	out->cmd = cmd;
 	out->cb = cb;
 	out->errcb = errcb;
@@ -556,7 +562,7 @@ static const jsmntok_t *sync_req(const tal_t *ctx,
 	const jsmntok_t *contents;
 	int reqlen;
 	struct json_out *jout = json_out_new(tmpctx);
-	const char *id = get_json_id(tmpctx, plugin, "init", method);
+	const char *id = append_json_id(tmpctx, plugin, method, "init/");
 
 	json_out_start(jout, NULL, '{');
 	json_out_addstr(jout, "jsonrpc", "2.0");
diff --git a/plugins/libplugin.h b/plugins/libplugin.h
index b5d2ae5e4..57fd44609 100644
--- a/plugins/libplugin.h
+++ b/plugins/libplugin.h
@@ -110,6 +110,7 @@ const struct feature_set *plugin_feature_set(const struct plugin *p);
 struct out_req *jsonrpc_request_start_(struct plugin *plugin,
 				       struct command *cmd,
 				       const char *method,
+				       const char *id_prefix,
 				       struct command_result *(*cb)(struct command *command,
 								    const char *buf,
 								    const jsmntok_t *result,
@@ -124,6 +125,7 @@ struct out_req *jsonrpc_request_start_(struct plugin *plugin,
  * "error" members. */
 #define jsonrpc_request_start(plugin, cmd, method, cb, errcb, arg)	\
 	jsonrpc_request_start_((plugin), (cmd), (method),		\
+		     json_id_prefix(tmpctx, (cmd)),			\
 		     typesafe_cb_preargs(struct command_result *, void *, \
 					 (cb), (arg),			\
 					 struct command *command,	\
@@ -139,8 +141,8 @@ struct out_req *jsonrpc_request_start_(struct plugin *plugin,
 
 /* This variant has callbacks received whole obj, not "result" or
  * "error" members.  It also doesn't start params{}. */
-#define jsonrpc_request_whole_object_start(plugin, cmd, method, cb, arg) \
-	jsonrpc_request_start_((plugin), (cmd), (method),		\
+#define jsonrpc_request_whole_object_start(plugin, cmd, method, id_prefix, cb, arg) \
+	jsonrpc_request_start_((plugin), (cmd), (method), (id_prefix),	\
 			       typesafe_cb_preargs(struct command_result *, void *, \
 						   (cb), (arg),		\
 						   struct command *command, \
@@ -470,6 +472,9 @@ struct createonion_response *json_to_createonion_response(const tal_t *ctx,
 struct route_hop *json_to_route(const tal_t *ctx, const char *buffer,
 				const jsmntok_t *toks);
 
+/* Create a prefix (ending in /) for this cmd_id, if any. */
+const char *json_id_prefix(const tal_t *ctx, const struct command *cmd);
+
 #if DEVELOPER
 struct htable;
 void plugin_set_memleak_handler(struct plugin *plugin,
diff --git a/plugins/test/run-route-overlong.c b/plugins/test/run-route-overlong.c
index ba87bb1cd..a20778629 100644
--- a/plugins/test/run-route-overlong.c
+++ b/plugins/test/run-route-overlong.c
@@ -107,6 +107,9 @@ void json_array_start(struct json_stream *js UNNEEDED, const char *fieldname UNN
 const jsmntok_t *json_get_member(const char *buffer UNNEEDED, const jsmntok_t tok[] UNNEEDED,
 				 const char *label UNNEEDED)
 { fprintf(stderr, "json_get_member called!\n"); abort(); }
+/* Generated stub for json_id_prefix */
+const char *json_id_prefix(const tal_t *ctx UNNEEDED, const struct command *cmd UNNEEDED)
+{ fprintf(stderr, "json_id_prefix called!\n"); abort(); }
 /* Generated stub for json_next */
 const jsmntok_t *json_next(const jsmntok_t *tok UNNEEDED)
 { fprintf(stderr, "json_next called!\n"); abort(); }
@@ -184,6 +187,7 @@ bool json_tok_streq(const char *buffer UNNEEDED, const jsmntok_t *tok UNNEEDED,
 struct out_req *jsonrpc_request_start_(struct plugin *plugin UNNEEDED,
 				       struct command *cmd UNNEEDED,
 				       const char *method UNNEEDED,
+				       const char *id_prefix UNNEEDED,
 				       struct command_result *(*cb)(struct command *command UNNEEDED,
 								    const char *buf UNNEEDED,
 								    const jsmntok_t *result UNNEEDED,
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index 7f127d75d..c2d06580c 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -2608,7 +2608,8 @@ def test_plugin_shutdown(node_factory):
 
 
 def test_commando(node_factory, executor):
-    l1, l2 = node_factory.line_graph(2, fundchannel=False)
+    l1, l2 = node_factory.line_graph(2, fundchannel=False,
+                                     opts={'log-level': 'io'})
 
     # Nothing works until we've issued a rune.
     fut = executor.submit(l2.rpc.call, method='commando',
@@ -2634,6 +2635,11 @@ def test_commando(node_factory, executor):
     assert len(res['peers']) == 1
     assert res['peers'][0]['id'] == l2.info['id']
 
+    # Check JSON id is as expected (unfortunately pytest does not use a reliable name
+    # for itself: with -k it calls itself `-c` here, instead of `pytest`).
+    l2.daemon.wait_for_log(r'plugin-commando: "[^:/]*:commando#[0-9]*/cln:commando#[0-9]*"\[OUT\]')
+    l1.daemon.wait_for_log(r'jsonrpc#[0-9]*: "[^:/]*:commando#[0-9]*/cln:commando#[0-9]*/commando:listpeers#[0-9]*"\[IN\]')
+
     res = l2.rpc.call(method='commando',
                       payload={'peer_id': l1.info['id'],
                                'rune': rune,