diff --git a/pkgs/development/interpreters/tcl/generic.nix b/pkgs/development/interpreters/tcl/generic.nix
index f5d3e863361d..d5c4b775473f 100644
--- a/pkgs/development/interpreters/tcl/generic.nix
+++ b/pkgs/development/interpreters/tcl/generic.nix
@@ -226,7 +226,9 @@ stdenv.mkDerivation (finalAttrs: {
         { buildPackages }:
         makeSetupHook {
           name = "tcl-requires-check-hook";
-          propagatedBuildInputs = [ buildPackages.makeBinaryWrapper ];
+          substitutions = {
+            tcl_hook = ./tcl-requires-check-hook.tcl;
+          };
           meta = {
             inherit (finalAttrs.meta) maintainers platforms;
             license = lib.licenses.mit;
diff --git a/pkgs/development/interpreters/tcl/tcl-requires-check-hook.sh b/pkgs/development/interpreters/tcl/tcl-requires-check-hook.sh
index 76c5901f2a33..6e3066d03b48 100644
--- a/pkgs/development/interpreters/tcl/tcl-requires-check-hook.sh
+++ b/pkgs/development/interpreters/tcl/tcl-requires-check-hook.sh
@@ -6,27 +6,8 @@ tclRequiresCheckPhase () {
 
     if [ -n "$tclRequiresCheck" ]; then
         export TCLLIBPATH="$out/lib $TCLLIBPATH" # Redundant if tcl-package-hook is also used
-        tclsh <<'EOF'
-          if {[info exists env(NIX_ATTRS_JSON_FILE)]} {
-            set nix_attrs_json_file [open $env(NIX_ATTRS_JSON_FILE)]
-            set nix_attrs_json [read $nix_attrs_json_file]
-            close $nix_attrs_json_file
-            # Normally we'd use one of tcllib/tdom/rl_json/yajl-tcl to parse JSON,
-            # however we don't want to introduce a circular dependency,
-            # so we rely on the JSON capabilities of the builtin sqlite package
-            # https://wiki.tcl-lang.org/page/SQLite+extension+JSON1
-            package require sqlite3
-            sqlite3 db :memory: -readonly 1
-            set packages_to_check [db eval {
-              select value from json_each(jsonb_extract($nix_attrs_json, '$.tclRequiresCheck'))
-            }]
-            db close
-          } else {
-            set packages_to_check $env(tclRequiresCheck)
-          }
-          puts "Check whether the following packages can be required: $packages_to_check"
-          exit [catch {foreach pkg $packages_to_check {package require $pkg}}]
-EOF
+        # FIXME: For some reason the output gets swallowed unless we pipe it through cat‽
+        tclsh @tcl_hook@ 2>&1 | cat
     fi
 }
 
diff --git a/pkgs/development/interpreters/tcl/tcl-requires-check-hook.tcl b/pkgs/development/interpreters/tcl/tcl-requires-check-hook.tcl
new file mode 100644
index 000000000000..ee373586144a
--- /dev/null
+++ b/pkgs/development/interpreters/tcl/tcl-requires-check-hook.tcl
@@ -0,0 +1,20 @@
+#!/usr/bin/env tclsh
+if {[info exists env(NIX_ATTRS_JSON_FILE)]} {
+  set nix_attrs_json_file [open $env(NIX_ATTRS_JSON_FILE)]
+  set nix_attrs_json [read $nix_attrs_json_file]
+  close $nix_attrs_json_file
+  # Normally we'd use one of tcllib/tdom/rl_json/yajl-tcl to parse JSON,
+  # however we don't want to introduce a circular dependency,
+  # so we rely on the JSON capabilities of the builtin sqlite package
+  # https://wiki.tcl-lang.org/page/SQLite+extension+JSON1
+  package require sqlite3
+  sqlite3 db :memory: -readonly 1
+  set packages_to_check [db eval {
+    select value from json_each(jsonb_extract($nix_attrs_json, '$.tclRequiresCheck'))
+  }]
+  db close
+} else {
+  set packages_to_check $env(tclRequiresCheck)
+}
+puts "Check whether the following packages can be required: $packages_to_check"
+foreach pkg $packages_to_check {package require $pkg}