CLI Authentication - FirstSales Developer

Use environment variables for agents and CI:

export FIRSTSALES_API_KEY="fs_..."
export FIRSTSALES_BASE_URL="https://api.app.firstsales.io"

Or pass flags:

firstsales whoami --api-key "$FIRSTSALES_API_KEY" --base-url https://api.app.firstsales.io

The CLI supports local profiles for developer machines. Environment variables are preferred for automation because they are explicit and easier to rotate.