asdf

One CLI, one config file, every runtime. asdf installs tools, generates shims for their executables, and picks a version per-directory at execution time.

Target: asdf 0.16+ (the Go rewrite). 0.15 and earlier were Bash and had a different command set. Check before doing anything else — the wrong assumption here produces commands that silently do not exist:

asdf version   # 0.16.0+ → this skill applies as written
               # 0.15.x or lower → read references/migration.md first

Mental model

Four facts explain nearly every asdf behavior and every asdf bug report: