diff --git a/home/jashton.nix b/home/jashton.nix
index 34237d8..327ba08 100644
--- a/home/jashton.nix
+++ b/home/jashton.nix
@@ -82,21 +82,24 @@ in
 
     (pkgs.writeShellScriptBin "jbuild" ''
       set -euo pipefail
-      # Assign first: `cd "$(jroot)"` would swallow a jroot failure, because
-      # `cd ""` is a successful no-op and set -e never sees the error.
+      if [ $# -lt 1 ]; then
+        echo "usage: jrun <package.MainClass> [args...]" >&2
+        exit 1
+      fi
+
       ROOT="$(jroot)"
       cd "$ROOT"
       mkdir -p bin
-      SOURCES="$(mktemp)"
-      trap 'rm -f "$SOURCES"' EXIT
-      find . -path ./bin -prune -o -name '.*' -prune -o -name '*.java' -print > "$SOURCES"
+
+      SOURCES="$1"
+      
+      find "$SOURCES" -name '*.java' -path '*.java'
+
       if [ ! -s "$SOURCES" ]; then
-        echo "jbuild: no .java files found under $ROOT" >&2
+        echo "jbuild: no .java files found under ./$SOURCES" >&2
         exit 1
       fi
-      # bin is deliberately NOT on the compile classpath: every source is passed
-      # explicitly, so a stale .class from a deleted file would silently satisfy
-      # references that ought to fail.
+
       javac -g --release 21 -encoding UTF-8 -d bin -cp "lib/*" @"$SOURCES"
     '')
 
@@ -114,14 +117,19 @@ in
         exit 1
       fi
       ROOT="$(jroot)"
-      jbuild
       cd "$ROOT"
+      jbuild $1
       MAIN="$1"; shift
-      exec java -cp "bin:lib/*" "$MAIN" "$@"
+      java -cp "bin:lib/*" "$MAIN" "$@"
     '')
 
     (pkgs.writeShellScriptBin "jtest" ''
       set -euo pipefail
+      if [ "$#" -lt 1 ]; then
+        echo "usage: jtest <package.MainClass> [args...]"
+        exit 1
+      fi
+
       # sort -V so 1.10.2 beats 1.9.0; plain tail -n1 sorts those the wrong way.
       JUNIT="$(ls -1 "$HOME"/dev/jars/junit-platform-console-standalone-*.jar 2>/dev/null | sort -V | tail -n1 || true)"
       if [ -z "$JUNIT" ]; then
@@ -133,15 +141,15 @@ in
       # on :5005 (see the "Attach to jtest" config in nvim.nix), so breakpoints
       # set before running jtest --debug are hit from the very first test.
       DEBUG_ARGS=()
-      if [ "''${1:-}" = "--debug" ]; then
+      if [[ "$1" = "debug" ]]; then
         DEBUG_ARGS=(-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=*:5005)
         shift
         echo "jtest: waiting for debugger to attach on 127.0.0.1:5005..." >&2
       fi
 
       ROOT="$(jroot)"
-      jbuild
       cd "$ROOT"
+      jbuild "$1"
       if [ $# -eq 0 ]; then
         exec java "''${DEBUG_ARGS[@]}" -jar "$JUNIT" execute --class-path "bin:lib/*" --scan-class-path --details=tree
       fi