diff --git a/scripts/fixtures/stub-worker.mjs b/scripts/fixtures/stub-worker.mjs
index ce777b6..e138201 100644
--- a/scripts/fixtures/stub-worker.mjs
+++ b/scripts/fixtures/stub-worker.mjs
@@ -1,7 +1,7 @@
 // Stands in for kimodo-resident-worker.py in the daemon's tests. It binds port 0, prints the ready line the
 // daemon waits for, and answers /health and /generate with what the daemon gave it. The --model value picks a
 // misbehaviour: crash-before-ready, hang-before-ready, sick, slow-health, stubborn, fail-generate,
-// refuse-generate, drop-generate, slow-generate, writer (appends to <output>.writes every 50 ms, never answers, ignores SIGTERM), slow-to-stop (no answer; prints a line and exits 1.5 s after SIGTERM), chatty (prints a line the moment it is healthy), encoder (a grandchild, then no answer), graceful (exits 0.5 s after SIGTERM), die-after-ready, bvh-outside (lists a BVH outside the job's directory), bvh-link (lists a symlink as its BVH), bvh-fifo (lists a FIFO as its BVH), plant-link (a normal answer with a file symlink and a directory symlink planted beside the BVH), no-loops (a normal answer that leaves out the loops a loop request asked for), bad-loops (loops whose window is not a frame range), short-loops (one window fewer than samples). A loop request is answered with loops, sample k as {first 3 + k, last 223 + k}. A request with bvh writes <output>.bvh (motion/motion_NN.bvh for several samples) and lists it. Any other value is just the model the worker serves.
+// refuse-generate, drop-generate, slow-generate, writer (appends to <output>.writes every 50 ms, never answers, ignores SIGTERM), slow-to-stop (no answer; prints a line and exits 1.5 s after SIGTERM), chatty (prints a line the moment it is healthy), encoder (a grandchild, then no answer), graceful (exits 0.5 s after SIGTERM), die-after-ready, bvh-outside (lists a BVH outside the job's directory), bvh-link (lists a symlink as its BVH), bvh-fifo (lists a FIFO as its BVH), plant-link (a normal answer with a file symlink and a directory symlink planted beside the BVH), no-loops (a normal answer that leaves out the loops a loop request asked for), bad-loops, negative-loops, empty-loops, fractional-last-loops (loops whose window is not a frame range: a fractional first, a negative first, first equal to last, a fractional last), short-loops (one window fewer than samples). A loop request is answered with loops, sample k as {first 3 + k, last 223 + k}. A request with bvh writes <output>.bvh (motion/motion_NN.bvh for several samples) and lists it. Any other value is just the model the worker serves.
 import http from "node:http";
 import os from "node:os";
 import path from "node:path";
@@ -14,6 +14,12 @@ const flag = (name) => {
   return index < 0 ? undefined : argv[index + 1];
 };
 const model = flag("--model");
+const BAD_WINDOWS = {
+  "bad-loops": { first: 5.5, last: 9 },
+  "negative-loops": { first: -1, last: 9 },
+  "empty-loops": { first: 7, last: 7 },
+  "fractional-last-loops": { first: 5, last: 9.5 },
+};
 const spawnLog = path.join(process.env.VILI_EMBEDDINGS_DIR, "stub-spawns.log");
 let requests = 0;
 let healthCalls = 0;
@@ -118,9 +124,8 @@ if (model === "hang-before-ready") {
           metaSeed: payload.meta?.seed,
           bvh: payload.bvh,
           ...(payload.loop && model !== "no-loops" ? {
-            loops: Array.from({ length: payload.numSamples - (model === "short-loops" ? 1 : 0) }, (_, k) => (model === "bad-loops"
-              ? { first: 5.5, last: 9, poseCost: 0, velocityCost: 0 }
-              : { first: 3 + k, last: 223 + k, poseCost: 0.03, velocityCost: 0.2 })),
+            loops: Array.from({ length: payload.numSamples - (model === "short-loops" ? 1 : 0) }, (_, k) => (BAD_WINDOWS[model]
+              ?? { first: 3 + k, last: 223 + k, poseCost: 0.03, velocityCost: 0.2 })),
           } : {}),
           bvhStandardTpose: payload.bvhStandardTpose,
           model: model || "stub-model",
diff --git a/scripts/test-vili-daemon.mjs b/scripts/test-vili-daemon.mjs
index dc3ffaf..6f56fe8 100644
--- a/scripts/test-vili-daemon.mjs
+++ b/scripts/test-vili-daemon.mjs
@@ -1480,30 +1480,6 @@ test("loop asks for the seamless window, and the window is the FBX's frame range
   }
 });
 
-test("constraints given twice are refused before anything is written or spawned", async () => {
-  const daemon = await startDaemon();
-  try {
-    const inline = [{ type: "root2d" }];
-    for (const bad of [
-      { constraints: inline, constraints_path: "/canary/a.json" },
-      { constraints: inline, constraintsPath: "/canary/a.json" },
-      { constraints: "/canary/a.json", constraints_path: "/canary/b.json" },
-      { constraints_path: "/canary/a.json", constraintsPath: "/canary/b.json" },
-    ]) {
-      const answer = await generate(daemon, exportRequest(bad));
-      assert.equal(answer.status, 400, JSON.stringify(bad));
-      assert.deepEqual(answer.body, { ok: false, error: "Invalid constraints request." });
-      assert.ok(!answer.raw.includes("canary"), "the refusal repeated the input");
-    }
-    assert.equal(existsSync(path.join(daemon.stateRoot, "artifacts")), false, "no artifact directory was made");
-    assert.deepEqual(jobFiles(daemon), []);
-    assert.deepEqual(daemon.spawns(), [], "no worker was started");
-    assert.equal((await generate(daemon, exportRequest({ constraints_path: "/some/where.json" }))).status, 200, "one input is fine");
-  } finally {
-    await daemon.stop();
-  }
-});
-
 test("past 100 samples each clip is exported over the window of its own sample", async () => {
   const daemon = await startDaemon();
   try {
@@ -1568,7 +1544,7 @@ test("loop is a boolean and needs fbx, refused before anything is written or spa
 });
 
 test("a loop request whose answer has no usable window for a sample fails without exporting that sample", async () => {
-  for (const [model, exported] of [["no-loops", 0], ["bad-loops", 0], ["short-loops", 1]]) {
+  for (const [model, exported] of [["no-loops", 0], ["bad-loops", 0], ["negative-loops", 0], ["empty-loops", 0], ["fractional-last-loops", 0], ["short-loops", 1]]) {
     const daemon = await startDaemon();
     try {
       const answer = await generate(daemon, exportRequest({ model, loop: true, numSamples: 2 }));
diff --git a/scripts/test_bvh_to_fbx.py b/scripts/test_bvh_to_fbx.py
index 844efec..5ce081d 100644
--- a/scripts/test_bvh_to_fbx.py
+++ b/scripts/test_bvh_to_fbx.py
@@ -242,14 +242,16 @@ class BvhToFbx(unittest.TestCase):
 
     def test_frames_outside_the_take_or_malformed_exit_without_a_file(self):
         bvh = self.walk("short", 31)
-        for index, (frames, exit_code) in enumerate((
-            (("0", "10"), 4), (("5", "32"), 4), (("10", "10"), 4), (("20", "10"), 4),
-            (("5",), 3), (("a", "9"), 3), (("-1", "9"), 3),
+        for index, (arguments, exit_code) in enumerate((
+            (("--frames", "0", "10"), 4), (("--frames", "5", "32"), 4), (("--frames", "10", "10"), 4),
+            (("--frames", "20", "10"), 4),
+            (("--frames", "5"), 3), (("--frames", "a", "9"), 3), (("--frames", "-1", "9"), 3),
+            (("--frames", "4", "20", "9"), 3), (("--range", "4", "20"), 3), (("4", "20"), 3),
         )):
             fbx = self.dir / f"refused{index}.fbx"
-            run = blender("--python", str(SCRIPT), "--", str(bvh), str(fbx), "refused", "--frames", *frames)
-            self.assertEqual(run.returncode, exit_code, frames)
-            self.assertFalse(fbx.exists(), frames)
+            run = blender("--python", str(SCRIPT), "--", str(bvh), str(fbx), "refused", *arguments)
+            self.assertEqual(run.returncode, exit_code, arguments)
+            self.assertFalse(fbx.exists(), arguments)
 
 
 if __name__ == "__main__":