Update dsl-reference.md

Co-authored-by: Ricardo Zanini <[email protected]>
Signed-off-by: amin-nikanjam <[email protected]>

Author: amin-nikanjam

dsl-reference.md

@@ -531,7 +531,7 @@ do:
 
 ##### MCP Call
 
-The [MCP Call](#mcp-call) enables workflows to interact with MCP servers that used by AI agents (https://modelcontextprotocol.io/).
+The [MCP Call](#mcp-call) enables workflows to interact with MCP servers that are used by AI agents (https://modelcontextprotocol.io/).
 
 ###### Properties