diff --git a/fortitude.toml b/fortitude.toml
index a29338ac..a2e923b6 100644
--- a/fortitude.toml
+++ b/fortitude.toml
@@ -6,7 +6,6 @@ ignore = [
   "S102", # incorrect-space-before-comment, we should enable this, autofix enable
   "M011", # use-all (should use "only:")
   "M001", # procedure-not-in-module (need a per-file ignore for init.F90)
-  "T031", # missing-intent
   "T042", # assumed-size-character-intent TODO: We should fix all instances!
 ]
 line-length = 132
diff --git a/src/en_restraint.F90 b/src/en_restraint.F90
index 6289b820..dde43bee 100644
--- a/src/en_restraint.F90
+++ b/src/en_restraint.F90
@@ -166,7 +166,7 @@ subroutine energy_restraint(x, y, z, px, py, pz, eclas)
             eclas = eclas ! + quadratic_restraint_energy
 
             !Output to en_restraint.dat
-            write (UERMD, '(I8,F16.8,E20.10,E20.10,F16.8)') it, excE * AUTOEV, deltaE, 0.0, 0.0
+            write (UERMD, '(I8,F16.8,E20.10,E20.10,F16.8)') it, excE * AUTOEV, deltaE, 0.0D0, 0.0D0
 
          end if
 
diff --git a/src/fftw_interface.F90 b/src/fftw_interface.F90
index 7690bd70..b782f5ec 100644
--- a/src/fftw_interface.F90
+++ b/src/fftw_interface.F90
@@ -72,16 +72,16 @@ subroutine fftw_normalmodes_init(nwalk)
    end subroutine fftw_normalmodes_init
 
    subroutine dft_normalmode2cart(nm, cart)
-      complex(C_DOUBLE_COMPLEX), dimension(:) :: nm
-      real(C_DOUBLE), dimension(:) :: cart
+      complex(C_DOUBLE_COMPLEX), dimension(:), intent(inout) :: nm
+      real(C_DOUBLE), dimension(:), intent(inout) :: cart
       cart = 0.0D0
       nm = (0.0D0, 0.0D0)
       call not_compiled_with('FFTW library')
    end subroutine dft_normalmode2cart
 
    subroutine dft_cart2normalmode(cart, nm)
-      complex(C_DOUBLE_COMPLEX), dimension(:) :: nm
-      real(C_DOUBLE), dimension(:) :: cart
+      complex(C_DOUBLE_COMPLEX), dimension(:), intent(inout) :: nm
+      real(C_DOUBLE), dimension(:), intent(inout) :: cart
       cart = 0.0D0
       nm = (0.0D0, 0.0D0)
       call not_compiled_with('FFTW library')
diff --git a/src/fortran_interfaces.F90 b/src/fortran_interfaces.F90
index fc4aabe0..182937a3 100644
--- a/src/fortran_interfaces.F90
+++ b/src/fortran_interfaces.F90
@@ -68,7 +68,7 @@ end subroutine omp_set_num_threads
       function usleep(useconds) bind(c, name='usleep')
          import :: C_INT, C_INT32_T
          implicit none
-         integer(kind=C_INT32_T), value :: useconds
+         integer(kind=C_INT32_T), intent(in), value :: useconds
          integer(kind=C_INT) :: usleep
       end function usleep
 
diff --git a/src/modules.F90 b/src/modules.F90
index 23047cd1..4734e23e 100644
--- a/src/modules.F90
+++ b/src/modules.F90
@@ -62,7 +62,7 @@ end subroutine set_natom
 
    subroutine update_simtime(dt)
       use mod_const, only: DP
-      real(DP) :: dt
+      real(DP), intent(in) :: dt
       sim_time = sim_time + dt
    end subroutine update_simtime
 end module mod_general
diff --git a/src/nosehoover.F90 b/src/nosehoover.F90
index ea0e49ff..336a461b 100644
--- a/src/nosehoover.F90
+++ b/src/nosehoover.F90
@@ -445,9 +445,10 @@ end function get_nhc_temp
    ! Suzuki-Yoshida split-operator integrator for global NHC
    subroutine shiftNHC_yosh(px, py, pz, amt, dt)
       use mod_system, only: dime
-      real(DP) :: px(:, :), py(:, :), pz(:, :)
-      real(DP) :: amt(:, :), G(MAXCHAIN)
-      real(DP) :: dt, ekin2, AA
+      real(DP), intent(inout) :: px(:, :), py(:, :), pz(:, :)
+      real(DP), intent(in) :: amt(:, :), dt
+      real(DP) :: G(MAXCHAIN)
+      real(DP) :: ekin2, AA
       real(DP) :: wdt, wdt2, wdt4, pscale
       integer :: iw, iat, inh
       integer :: nf, iresp, iyosh
@@ -528,11 +529,10 @@ end subroutine shiftNHC_yosh
    subroutine shiftNHC_yosh_mass(px, py, pz, amt, dt)
       use mod_general
       use mod_shake, only: nshake
-      real(DP) :: px(:, :), py(:, :), pz(:, :)
-      real(DP) :: amt(:, :)
+      real(DP), intent(inout) :: px(:, :), py(:, :), pz(:, :)
+      real(DP), intent(in) :: amt(:, :), dt
       real(DP) :: Gx(MAXCHAIN), Gy(MAXCHAIN), Gz(MAXCHAIN)
-      real(DP) :: dt, AA
-      real(DP) :: wdt, wdt2, wdt4
+      real(DP) :: AA, wdt, wdt2, wdt4
       integer :: iw, iat, inh, istart
       integer :: iresp, iyosh
 
diff --git a/src/pbc.F90 b/src/pbc.F90
index 61da04e3..dca94a51 100644
--- a/src/pbc.F90
+++ b/src/pbc.F90
@@ -14,7 +14,7 @@ module PBC
 
    subroutine wrap(x, y, z)
       use mod_general, only: nwalk
-      real(DP) :: x(:, :), y(:, :), z(:, :)
+      real(DP), intent(inout) :: x(:, :), y(:, :), z(:, :)
       integer :: i, iat, iat2, iw, iww, iwrap
 
       iwrap = 0
diff --git a/src/random.F90 b/src/random.F90
index 18f78209..8712ba3e 100644
--- a/src/random.F90
+++ b/src/random.F90
@@ -705,7 +705,7 @@ end subroutine random_ints
    ! Taken from:
    ! https://gcc.gnu.org/onlinedocs/gcc-4.9.1/gfortran/RANDOM_005fSEED.html
    integer function lcg(s)
-      integer(INT64) :: s
+      integer(INT64), intent(inout) :: s
 
       if (s == 0) then
          s = 104729