FX CLI (experimental)

Happier runs your locally installed FX CLI through fx acp. The interactive fx command is a separate terminal surface. Happier does not claim that an interactive FX session and an ACP session share identity.

What you need first

Install FX with the official installation guide, then authenticate on the machine where Happier runs:

fx login
fx status

FX can also use AI_GATEWAY_API_KEY or another credential source supported by its current authentication settings.

Start and resume sessions

happier fx

Happier supports fresh and resumed FX sessions, cancellation, execution runs, and FX's advertised model and mode controls. Happier does not maintain a separate static FX model list; the choices shown in the app come from ACP.

When creating a new session, the Resume field can browse session IDs that fx acp reports through ACP session/list for the selected directory and pick one to resume. These entries are resume-only. Listing them does not establish that they are interactive-terminal sessions, and Happier does not provide live takeover, writer safety, transcript following or import, or terminal attachment for them.

FX combines MCP servers selected for the Happier session with approved project servers. See MCP servers for the shared setup flow.

When it goes wrong

• Run fx doctor when startup, credentials, or saved sessions fail.
• Run fx models --json to inspect models available to the active credential.
• If fx is not found after installation, start a new shell or add ~/.local/bin to PATH.

Related

• Agent capabilities
• Model and engine selection