diff --git a/plugins/code-oz/scripts/resolve-code-oz.sh b/plugins/code-oz/scripts/resolve-code-oz.sh
index 9a3c297..f8ee413 100755
--- a/plugins/code-oz/scripts/resolve-code-oz.sh
+++ b/plugins/code-oz/scripts/resolve-code-oz.sh
@@ -68,6 +68,22 @@ case "${OS_NAME}" in
     ;;
 esac
 
+# ---------------------------------------------------------------------------
+# Drop empty-string positional arguments before resolution. A plugin command
+# card renders `<subcommand> "$ARGUMENTS"`; with no user arguments Claude Code
+# substitutes an empty $ARGUMENTS, leaving a literal "" that the engine's
+# subcommand dispatcher (0.21.1+) rejects as an unknown subcommand. An empty
+# positional is never meaningful to code-oz, so the launcher strips it before
+# both the PATH-exec and npx branches. The array form preserves args that
+# contain spaces; ${a[@]+"${a[@]}"} is the bash-3.2 + `set -u`-safe way to
+# expand a possibly-empty array.
+# ---------------------------------------------------------------------------
+filtered_args=()
+for arg in "$@"; do
+  [ -n "${arg}" ] && filtered_args+=("${arg}")
+done
+set -- ${filtered_args[@]+"${filtered_args[@]}"}
+
 # ---------------------------------------------------------------------------
 # 2. code-oz found on PATH — exec directly, forwarding all args.
 # ---------------------------------------------------------------------------
diff --git a/tests/plugins/bootstrap-resolver.test.ts b/tests/plugins/bootstrap-resolver.test.ts
index b6c8e3d..9a58bad 100644
--- a/tests/plugins/bootstrap-resolver.test.ts
+++ b/tests/plugins/bootstrap-resolver.test.ts
@@ -122,6 +122,42 @@ describe('resolve-code-oz.sh — PATH binary present', () => {
     expect(result.stdout).toContain('--provider')
     expect(result.stdout).toContain('fake')
   })
+
+  test('strips an empty-string positional before exec (no-args plugin card artifact)', async () => {
+    // A plugin command card renders `<subcommand> "$ARGUMENTS"`. With no user
+    // arguments Claude Code substitutes an empty $ARGUMENTS, leaving a literal
+    // `doctor ""`. The empty positional must not reach the engine, whose 0.21.1
+    // subcommand dispatcher rejects '' as an unknown subcommand. The fake wraps
+    // each forwarded arg in brackets, so an empty arg would appear as `[]`.
+    const fakeDir = await makeFakeBinDir({
+      'code-oz': `#!/bin/sh\nprintf 'ARGS:'\nfor a in "$@"; do printf '[%s]' "$a"; done\nprintf '\\n'\n`,
+    })
+
+    const result = await runResolver({
+      path: `${fakeDir}:${SYSTEM_BIN}`,
+      args: ['doctor', ''],
+    })
+
+    expect(result.exitCode).toBe(0)
+    expect(result.stdout).toContain('[doctor]')
+    expect(result.stdout).not.toContain('[]')
+  })
+
+  test('preserves a non-empty positional that contains spaces', async () => {
+    // The empty-arg filter must not word-split or drop legitimate args.
+    const fakeDir = await makeFakeBinDir({
+      'code-oz': `#!/bin/sh\nprintf 'ARGS:'\nfor a in "$@"; do printf '[%s]' "$a"; done\nprintf '\\n'\n`,
+    })
+
+    const result = await runResolver({
+      path: `${fakeDir}:${SYSTEM_BIN}`,
+      args: ['run', 'fix the login bug'],
+    })
+
+    expect(result.exitCode).toBe(0)
+    expect(result.stdout).toContain('[run]')
+    expect(result.stdout).toContain('[fix the login bug]')
+  })
 })
 
 describe('resolve-code-oz.sh — npx fallback', () => {
@@ -165,6 +201,21 @@ describe('resolve-code-oz.sh — npx fallback', () => {
     // The exact pinned version string must appear in the npx invocation
     expect(result.stdout).toContain(pinnedVersion)
   })
+
+  test('strips an empty-string positional before the npx invocation too', async () => {
+    const fakeDir = await makeFakeBinDir({
+      npx: `#!/bin/sh\nprintf 'ARGS:'\nfor a in "$@"; do printf '[%s]' "$a"; done\nprintf '\\n'\n`,
+    })
+
+    const result = await runResolver({
+      path: `${fakeDir}:${SYSTEM_BIN}`,
+      args: ['doctor', ''],
+    })
+
+    expect(result.exitCode).toBe(0)
+    expect(result.stdout).toContain('[doctor]')
+    expect(result.stdout).not.toContain('[]')
+  })
 })
 
 describe('resolve-code-oz.sh — npx failure surfaces scope-routing caveat', () => {