I'm not sure it meets the definition of a circumvention tool, which appears to be a reference to 'computer software.' As in, the legal definition for such. The courts use a specific definition, found by the entry in the above reply. The few cases I found made use of the specific terminology.
IANAL :-)
However, circumvention tools (software or otherwise) require suing, not merely issuing a takedown notice, as another commenter pointed out.