diff --git a/hermes_cli/tools_config.py b/hermes_cli/tools_config.py
index 2919148763..91c41dce5d 100644
--- a/hermes_cli/tools_config.py
+++ b/hermes_cli/tools_config.py
@@ -509,6 +509,10 @@ def _get_platform_tools(
         default_ts = PLATFORMS[platform]["default_toolset"]
         toolset_names = [default_ts]
 
+    # YAML may parse bare numeric names (e.g. ``12306:``) as int.
+    # Normalise to str so downstream sorted() never mixes types.
+    toolset_names = [str(ts) for ts in toolset_names]
+
     configurable_keys = {ts_key for ts_key, _, _ in CONFIGURABLE_TOOLSETS}
 
     # If the saved list contains any configurable keys directly, the user
@@ -567,7 +571,7 @@ def _get_platform_tools(
     # Special sentinel: "no_mcp" in the toolset list disables all MCP servers.
     mcp_servers = config.get("mcp_servers") or {}
     enabled_mcp_servers = {
-        name
+        str(name)
         for name, server_cfg in mcp_servers.items()
         if isinstance(server_cfg, dict)
         and _parse_enabled_flag(server_cfg.get("enabled", True), default=True)
diff --git a/tests/hermes_cli/test_tools_config.py b/tests/hermes_cli/test_tools_config.py
index 830bad8d5f..2c2bb39194 100644
--- a/tests/hermes_cli/test_tools_config.py
+++ b/tests/hermes_cli/test_tools_config.py
@@ -428,3 +428,31 @@ class TestPlatformToolsetConsistency:
                 f"Platform {platform!r} in tools_config but missing from "
                 f"skills_config PLATFORMS"
             )
+
+
+def test_numeric_mcp_server_name_does_not_crash_sorted():
+    """YAML parses bare numeric keys (e.g. ``12306:``) as int.
+
+    _get_platform_tools must normalise them to str so that sorted()
+    on the returned set never raises TypeError on mixed int/str.
+
+    Regression test for https://github.com/NousResearch/hermes-agent/issues/6901
+    """
+    config = {
+        "platform_toolsets": {"cli": ["web", 12306]},
+        "mcp_servers": {
+            12306: {"url": "https://example.com/mcp"},
+            "normal-server": {"url": "https://example.com/mcp2"},
+        },
+    }
+
+    enabled = _get_platform_tools(config, "cli")
+
+    # All names must be str — no int leaking through
+    assert all(isinstance(name, str) for name in enabled), (
+        f"Non-string toolset names found: {enabled}"
+    )
+    assert "12306" in enabled
+
+    # sorted() must not raise TypeError
+    sorted(enabled)