A year ago, the mainstream experience was inline autocomplete — suggest the next line, accept or reject. Current coding agents can read an entire codebase, plan a multi-file change, run the tests, and iterate on failures without a human re-prompting at every step.
Well-scoped, well-specified tasks — a bug with a clear repro, a feature with a clear acceptance criteria — see the biggest speedup. Ambiguous, judgment-heavy architectural decisions still benefit far more from a human thinking it through first.
The gap between "junior developer productivity" and "senior developer productivity" on well-specified tasks has narrowed, because the agent handles a lot of the mechanical implementation either way. The remaining differentiator is increasingly judgment on what to build and how to scope it — not typing speed.