diff --git a/package.json b/package.json
index 6f3bb9f..a8c62de 100644
--- a/package.json
+++ b/package.json
@@ -23,8 +23,8 @@
     "falsify:spatial": "node scripts/spatial/spatial-falsify.mjs out",
     "check:spatial-sync": "node scripts/spatial-sync.mjs --check",
     "check:illustrations": "node scripts/check-illustrations.mjs",
-    "check:streets": ".venv/bin/python scripts/illustrations/build_streets.py --check",
-    "build:streets": ".venv/bin/python scripts/illustrations/build_streets.py",
+    "check:streets": "node scripts/run-streets.mjs --check",
+    "build:streets": "node scripts/run-streets.mjs",
     "check:rules": "node scripts/authoring/build-rules.mjs --check"
   },
   "dependencies": {
diff --git a/scripts/run-streets.mjs b/scripts/run-streets.mjs
new file mode 100644
index 0000000..650a0f4
--- /dev/null
+++ b/scripts/run-streets.mjs
@@ -0,0 +1,28 @@
+/**
+ * Run the street-scene builder with the interpreter the illustration gate
+ * already uses.
+ *
+ * CI installs Pillow and NumPy into the setup-python interpreter and never
+ * creates a project .venv. A script that calls `.venv/bin/python` exits 127
+ * before the gate can measure a single picture, which is how `npm run verify`
+ * went red on the commit that added the streets. The order is the one the
+ * illustration toolchain already documents: `PYTHON` if set, otherwise the
+ * project `.venv`, otherwise `python3` on PATH.
+ */
+import { spawnSync } from "node:child_process";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import { illustrationPython } from "./check-illustrations.mjs";
+
+const script = path.join(
+  path.dirname(fileURLToPath(import.meta.url)),
+  "illustrations",
+  "build_streets.py",
+);
+const py = illustrationPython();
+const done = spawnSync(py, [script, ...process.argv.slice(2)], { stdio: "inherit" });
+if (done.error) {
+  console.error(`could not run ${py}: ${done.error.message}`);
+  process.exit(1);
+}
+process.exit(done.status ?? 1);
diff --git a/tests/streets.test.ts b/tests/streets.test.ts
index 1e1bc9e..8baa077 100644
--- a/tests/streets.test.ts
+++ b/tests/streets.test.ts
@@ -49,6 +49,17 @@ test("five pages stand in a Bangkok street, and each drawing appears once", () =
   }
 });
 
+test("the street gate resolves Python the way CI installs it", () => {
+  // setup-python puts Pillow on `python3` and does not create `.venv`.
+  // A script that names `.venv/bin/python` dies with exit 127, and the
+  // byte check never runs. The runner must share the illustration gate's
+  // resolver: PYTHON, then .venv, then python3 on PATH.
+  const pkg = JSON.parse(read("/package.json"));
+  assert.equal(pkg.scripts["check:streets"], "node scripts/run-streets.mjs --check");
+  assert.equal(pkg.scripts["build:streets"], "node scripts/run-streets.mjs");
+  assert.match(read("/scripts/run-streets.mjs"), /illustrationPython\(\)/);
+});
+
 test("every street the app names is a file that ships", () => {
   for (const [, src] of Object.entries(artMap())) {
     if (!src.includes("/illustrations/scene-")) continue;