Quick start

$curl -fsSL https://fx.sh/setup.sh | bash

The installer places fx in ~/.local/bin. Read Installation before piping the script to a shell, or if fx is not on your PATH afterward.

$fx login

fx login opens the Vercel authorization flow and saves the session for later runs. An AI Gateway API key works too; see Authentication.

Run your first request

Start fx from the project you want to work on. The launch directory becomes the primary workspace:

$cd path/to/project

$fx

Type a request that names real files or commands, then press enter:

Read src/ and tell me how requests are routed. Then add a test for the
error path in the router and run the test suite.

fx works in turns. The model's reply streams into the transcript, and each tool call appears as it runs while fx reads files, searches, and runs commands. Press escape or ctrl+c to interrupt the turn, and ctrl+o to open Review and the full transcript.

What fx asks before it acts

fx starts in auto permission mode. Saved rules are applied first, an unresolved sensitive call is reviewed automatically, and anything still unresolved becomes an approval prompt with three choices: run it once, run it and stop asking for that scope in this session, or decline.

Listing, globbing, searching, and reading files in the workspace do not need approval. The calls worth reading before you approve are the ones that change your machine or run code: write_file, edit_file, delete_file, rename_file, copy_file, create_folder, run_command, open_file, install_skill, and vision. Reaching a path outside the workspace is also subject to permission policy.

Switch modes with /permissions at any time, and see Permissions for rules, sandboxing, and the cost of automatic review.

Approve deliberately

An approval grants exactly the scope shown in the prompt. yolo mode disables fx permission checks and the command sandbox for that run, so use it only in a workspace and container you are willing to lose.

Things to know

In an interactive session, type / to open the available commands. See Slash commands for the full reference.

Need	Use
Open available commands	Type `/`
Find a file	Type `@`
Find a skill	Type `$`
Inspect the current model, workspace, permissions, and session	`/status`
Choose a model	`/models`
Change the permission mode	`/permissions`
Start a new session	`/new`
Attach an image	`/image ./path.png`
View local usage	`/usage`
Turn completion sounds on or off	`/sound on` or `/sound off`
Share feedback	`/feedback`
Create a private diagnostic trace	`/trace`

Every interactive command is listed in Slash commands.

Shortcuts

Action	Shortcut
Insert a newline	shift+enter, alt+enter, or backslash then enter
Move through prompt history	up or down at the edge of the draft
Interrupt the current turn	escape or ctrl+c
Open Review and Full transcript	ctrl+o, then left or right
Open the subagent manager	ctrl+x

Continue your work

Open the session picker to choose a saved session:

$fx -r

Resume the latest session for the current workspace directly:

$fx resume last