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VYN

VYN is the Vynthen coding agent for the terminal. It reads your project, proposes edits, runs commands and keeps you in control of every write. It uses the same account, models and token allowance as Vynthen App and Vynthen Build.

Install

The terminal agent is available from source today. Build it with Rust stable from the VYN workspace:

cd vyn
cargo build --release

# verify
./target/release/vyn --version

Signed installers are not published yet. See Download VYN for the current platform and release status.

Sign in

VYN uses a device code so your password never touches the terminal history. Run:

vyn login

VYN prints an eight-character code and opens vynthen.com/device. Confirm the device name, authorize it, and the terminal receives a token. Tokens are stored in your OS keychain when available.

Revoke a machine any time from Settings → Devices. Revoking takes effect immediately.

Work with a project

From the root of a repository:

vyn "add rate limiting to the login endpoint"

# explicit agent mode
vyn agent "fix the failing tests in src/auth"

# interactive session
vyn

VYN inspects the files it needs, proposes a plan, and asks before applying changes or running commands that write outside the project. Use /help inside the interactive session for commands and /exit to leave.

What it can do

• Read and search your project files.
• Write and edit files inside the current project.
• Run tests, formatters and build commands with your approval.
• Explain changes and keep a transcript of the session.

Safety

• File writes are restricted to the project directory.
• Destructive commands require explicit confirmation.
• Secrets in your environment are not sent to the model.
• Every device token can be revoked from Settings.

Configuration

VYN reads ~/.config/vyn/config.toml. You can set a default model, the API base URL, and whether to auto-approve read-only tools.

model = "ling-3.0-flash"
api_base = "https://vynthen.com"
auto_approve_reads = true

Plans and limits

VYN draws from the same token allowance as App and Build. Free includes Ling 3.0 Flash; Basic and above unlock more models and larger windows. On the BYOK plan, VYN uses the OpenRouter key stored in your account.

See pricing for the exact limits, or create an account to start.