How to enable shell completion

CONGA ships its own completion driver supporting bash, zsh, fish, powershell, elvish, and nushell. Scripts are generated from the same schema that powers parsing and help. How the driver and wire protocol work is covered in About the shell completion architecture.

Completion is opt-in: call app.EnableCompletion() on the builder. Apps that skip it keep --completion, the completion subcommand, and the __complete handler out of the binary entirely.

app := conga.New[CLI]().
  EnableCompletion().
  Name("mytool")

Generate a script

With completion enabled, flat, single-command CLIs provide a --completion <shell> flag:

$ mytool --completion bash >> ~/.bashrc

Apps with subcommands get a hidden __complete handler used by the generated shell functions; you can additionally expose an opt-in completion <shell> subcommand by declaring a conga.CompletionCommand field:

type App struct {
  Completion conga.CompletionCommand `name:"completion" summary:"Generate shell completion script"`
}

mytool completion on its own renders help, including per-shell install hints.

What completes automatically

• Flag names — long, short, and aliases, including negatable --no- forms; deprecated flags are omitted.
• Subcommand names, aliases, and groups, with did-you-mean behaviour in the shell editors.
• Enum-constrained flags and arguments complete their allowed values.
• Domain-typed fields — conga.File completes file paths, conga.Dir directories, conga.ByteSize unit suffixes, and so on. See Domain Types.
• Registered predictors — flags and arguments tagged predictor:"name" complete via the SDK. See How to wire custom completion.

Control completion

Builder call	Effect
app.EnableCompletion()	Enables completion support: flag, subcommand, and __complete handler. Off by default; apps that skip it do not link the drivers
app.Predictor(name, p)	Registers a named predictor for predictor:"name" tags

Fields with built-in semantics complete automatically; for your own types and registries, continue with How to wire custom completion.