Go

Normal code has tests; agents need evals. What an eval harness is, the vocabulary that goes with it, how I would build one in Go for an SRE agent working against Kubernetes, why pass^k matters more than pass@k for ops, the tools that exist (and the one OpenAI is shutting down), the ways a harness's numbers lie to you, and the habits that keep a suite useful.

I learned enough Rust in a weekend to read, review and debug the CLIs, API clients and daemons that show up in infra work. This is the subset that mattered, the compiler errors you will actually hit, and the parts of the language I deliberately skipped.