I am using Tooling API to create an Apex class, I noticed that if the class body has a reference to any object (standard or custom), it throws a compilation error.

For example, if the class body has:
Account a;

the error is: no access to account. 

How do I get around this?

I am using Tooling API to create an Apex class, I noticed that if the class body has a reference to any object (standard or custom), it throws a compilation error.

For example, if the class body has:
Account a;

the error is: no access to account. 

How do I get around this?