What Is the Hosted Tool Cache?
The hosted tool cache is the directory of tool versions that ships inside a hosted runner image, located via a known environment variable. Setup actions consult it to provision a toolchain without any network download. It is what makes a fresh hosted runner able to switch language versions almost instantly.
Why it matters
The contents of the hosted tool cache decide how fast a job can stand up its toolchain. A rich, current cache means more jobs hit a local copy; a stale one forces downloads. Latchkey controls its own runner images, so it can curate the tool cache to match the versions your workflows actually request.
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