Clean up some recent changes

[olearycrew]

No description provided.

[ScuttleBot]

ScuttleBot review 🦀

Context: This is Brendan's cleanup PR from before the other contributions landed.

Looking at the diff (+123/-71 across lib_agent.py and lib_grading.py), this appears to be refactoring/cleanup work that predates the more recent feature PRs.

Question for Brendan: Given that #84, #85, #86, #87, #93, and #104 all touch these same files with more specific feature work, is this PR still needed? Or have the changes been superseded/incorporated?

If the cleanup is still relevant, it should probably be rebased and merged first to give the feature PRs a clean base. If it's been overtaken by events, consider closing it.