diff --git a/packages/opencode/src/mcp/index.ts b/packages/opencode/src/mcp/index.ts
index 6b153e39..d6de4a59 100644
--- a/packages/opencode/src/mcp/index.ts
+++ b/packages/opencode/src/mcp/index.ts
@@ -242,8 +242,8 @@ export namespace MCP {
         continue
       }
       for (const [toolName, tool] of Object.entries(tools)) {
-        const sanitizedClientName = clientName.replace(/\s+/g, "_")
-        const sanitizedToolName = toolName.replace(/[-\s]+/g, "_")
+        const sanitizedClientName = clientName.replace(/[^a-zA-Z0-9_-]/g, "_")
+        const sanitizedToolName = toolName.replace(/[^a-zA-Z0-9_-]/g, "_")
         result[sanitizedClientName + "_" + sanitizedToolName] = tool
       }
     }