FX CLI (experimental)
Run FX through Happier with ACP sessions, dynamic models and modes, MCP tools, resume, and execution runs.
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 statusFX can also use AI_GATEWAY_API_KEY or another credential source supported by
its current authentication settings.
Start and resume sessions
happier fxHappier 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.
In the 0.2 development build, FX's provider selector remains a separate configuration control. The model picker shows actual models, with reasoning effort and fast controls for the selected model. Changing models refreshes the available control values; a rejected provider change keeps the last applied configuration and reports the error.
The automatic permission preset in that development build selects an automatic review mode advertised by FX, including the renamed mode in FX 0.0.14. It fails closed when no matching mode is advertised and never substitutes full access.
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 doctorwhen startup, credentials, or saved sessions fail. - Run
fx models --jsonto inspect models available to the active credential. - If
fxis not found after installation, start a new shell or add~/.local/bintoPATH.