GitHub is how Yardstick sees outcomes. Install the Yardstick GitHub App from the Connect page and grant it the repositories you want measured. It is a one-click install; you do not paste tokens.
What Yardstick reads: pull request metadata (opened, merged, reviewed, reverted), so we can attribute shipped work and change-failure. Yardstick does not need and does not store your source code; we work from the metadata about what shipped, not the contents of your files.
Once installed, new merged pull requests start showing up as outcomes and get attributed to the agent that helped ship them.