diff --git a/package.json b/package.json
index 25866d6189..523232b78b 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
   "type": "module",
   "scripts": {
     "dev": "bun run studio",
-    "build": "bun run --filter '@hyperframes/{parsers,lint,studio-server}' build && bun run --filter @hyperframes/core build && bun run --filter '@hyperframes/{core,engine,producer,player,studio,shader-transitions,aws-lambda,gcp-cloud-run,sdk}' build && bun run --filter @hyperframes/cli build && bun run --filter @hyperframes/sdk-playground build",
+    "build": "bun run --filter '@hyperframes/{parsers,lint,studio-server}' build && bun run --filter @hyperframes/core build && bun run --filter '@hyperframes/{engine,producer,player,studio,shader-transitions,aws-lambda,sdk}' build && bun run --filter @hyperframes/gcp-cloud-run build && bun run --filter @hyperframes/cli build && bun run --filter @hyperframes/sdk-playground build",
     "build:producer": "bun run --filter @hyperframes/producer build",
     "studio": "bun run --filter @hyperframes/studio dev",
     "build:hyperframes-runtime": "bun run --filter @hyperframes/core build:hyperframes-runtime",
@@ -48,7 +48,7 @@
     "player:perf": "bun run --filter @hyperframes/player perf",
     "format:check": "oxfmt --check .",
     "knip": "knip",
-    "test:scripts": "node --import tsx --test scripts/animejs-v4-guidance.test.mjs scripts/check-tracked-artifacts.test.mjs scripts/check-no-main-deletions.test.mjs scripts/check-docs-snippet-motion.test.mjs scripts/registry-target-paths.test.mjs scripts/check-workspace-contracts.test.mjs scripts/check-package-cycles.test.mjs scripts/check-cli-process-ownership.test.mjs scripts/check-large-files.test.mjs scripts/package-subpaths.test.mjs scripts/validate-release-channel.test.mjs scripts/publish-workflow.test.mjs scripts/install-workspace-dependencies.test.mjs scripts/draft-changelog.test.ts scripts/set-version.test.ts scripts/release-prepare.test.ts scripts/cli-options.test.ts scripts/changelog-weekly.test.ts scripts/claude-plugin-compression.test.ts scripts/catalog-payload-assets.test.ts scripts/catalog-preview-temp.test.ts scripts/player-cdn-pin.test.ts scripts/studio-runtime-smoke.test.mjs scripts/verify-packed-manifests.test.mjs scripts/lint-skills.test.mjs packages/gcp-cloud-run/check-dockerfile-workspaces.test.mjs && vitest run scripts/catalog/",
+    "test:scripts": "node --import tsx --test scripts/animejs-v4-guidance.test.mjs scripts/check-tracked-artifacts.test.mjs scripts/check-no-main-deletions.test.mjs scripts/check-docs-snippet-motion.test.mjs scripts/registry-target-paths.test.mjs scripts/check-workspace-contracts.test.mjs scripts/check-package-cycles.test.mjs scripts/check-cli-process-ownership.test.mjs scripts/check-large-files.test.mjs scripts/package-subpaths.test.mjs scripts/validate-release-channel.test.mjs scripts/publish-workflow.test.mjs scripts/install-workspace-dependencies.test.mjs scripts/draft-changelog.test.ts scripts/set-version.test.ts scripts/release-prepare.test.ts scripts/cli-options.test.ts scripts/changelog-weekly.test.ts scripts/claude-plugin-compression.test.ts scripts/catalog-payload-assets.test.ts scripts/catalog-preview-temp.test.ts scripts/player-cdn-pin.test.ts scripts/studio-runtime-smoke.test.mjs scripts/verify-packed-manifests.test.mjs scripts/lint-skills.test.mjs packages/core/scripts/atomic-write-file.test.ts packages/gcp-cloud-run/check-dockerfile-workspaces.test.mjs && vitest run scripts/catalog/",
     "typecheck:scripts": "tsc --noEmit -p scripts/tsconfig.json",
     "test:skills": "node --test 'skills/**/*.test.mjs'",
     "generate:previews": "tsx scripts/generate-template-previews.ts",
diff --git a/packages/core/scripts/atomic-write-file.test.ts b/packages/core/scripts/atomic-write-file.test.ts
new file mode 100644
index 0000000000..33c1bd2bf2
--- /dev/null
+++ b/packages/core/scripts/atomic-write-file.test.ts
@@ -0,0 +1,61 @@
+import assert from "node:assert/strict";
+import { mkdirSync, mkdtempSync, readFileSync, readdirSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { dirname, join } from "node:path";
+import test from "node:test";
+import { atomicWriteFileSync } from "./atomic-write-file.js";
+
+type FileSystemError = Error & { syscall: string; path: string; dest: string };
+
+function captureFileSystemError(operation: () => void): FileSystemError {
+  try {
+    operation();
+  } catch (error) {
+    assert.ok(error instanceof Error);
+    return error as FileSystemError;
+  }
+  assert.fail("expected filesystem operation to fail");
+}
+
+test("atomicWriteFileSync replaces the destination with complete contents", () => {
+  const directory = mkdtempSync(join(tmpdir(), "hyperframes-atomic-write-"));
+  const destination = join(directory, "artifact.js");
+
+  try {
+    writeFileSync(destination, "old contents", "utf8");
+
+    atomicWriteFileSync(destination, "new contents", "utf8");
+
+    assert.equal(readFileSync(destination, "utf8"), "new contents");
+    assert.deepEqual(readdirSync(directory), ["artifact.js"]);
+  } finally {
+    rmSync(directory, { recursive: true, force: true });
+  }
+});
+
+test("atomicWriteFileSync removes its temporary file when publication fails", () => {
+  const directory = mkdtempSync(join(tmpdir(), "hyperframes-atomic-write-failure-"));
+  const destination = join(directory, "artifact.js");
+
+  try {
+    mkdirSync(destination);
+
+    const firstFailure = captureFileSystemError(() =>
+      atomicWriteFileSync(destination, "first contents", "utf8"),
+    );
+    const secondFailure = captureFileSystemError(() =>
+      atomicWriteFileSync(destination, "second contents", "utf8"),
+    );
+
+    assert.equal(firstFailure.syscall, "rename");
+    assert.equal(secondFailure.syscall, "rename");
+    assert.equal(dirname(firstFailure.path), directory);
+    assert.equal(dirname(secondFailure.path), directory);
+    assert.equal(firstFailure.dest, destination);
+    assert.equal(secondFailure.dest, destination);
+    assert.notEqual(firstFailure.path, secondFailure.path);
+    assert.deepEqual(readdirSync(directory), ["artifact.js"]);
+  } finally {
+    rmSync(directory, { recursive: true, force: true });
+  }
+});
diff --git a/packages/core/scripts/atomic-write-file.ts b/packages/core/scripts/atomic-write-file.ts
new file mode 100644
index 0000000000..1d21beea0b
--- /dev/null
+++ b/packages/core/scripts/atomic-write-file.ts
@@ -0,0 +1,22 @@
+import { randomUUID } from "node:crypto";
+import { renameSync, rmSync, writeFileSync, type WriteFileOptions } from "node:fs";
+import { basename, dirname, join } from "node:path";
+
+export function atomicWriteFileSync(
+  destination: string,
+  contents: string | NodeJS.ArrayBufferView,
+  options?: WriteFileOptions,
+): void {
+  const temporaryPath = join(
+    dirname(destination),
+    `.${basename(destination)}.${process.pid}.${randomUUID()}.tmp`,
+  );
+
+  try {
+    writeFileSync(temporaryPath, contents, options);
+    renameSync(temporaryPath, destination);
+  } catch (error) {
+    rmSync(temporaryPath, { force: true });
+    throw error;
+  }
+}
diff --git a/packages/core/scripts/build-hyperframes-runtime-artifact.ts b/packages/core/scripts/build-hyperframes-runtime-artifact.ts
index 3042e17706..4b1cd5570c 100644
--- a/packages/core/scripts/build-hyperframes-runtime-artifact.ts
+++ b/packages/core/scripts/build-hyperframes-runtime-artifact.ts
@@ -1,8 +1,9 @@
 import { createHash } from "node:crypto";
-import { mkdirSync, writeFileSync } from "node:fs";
+import { mkdirSync } from "node:fs";
 import { dirname, resolve } from "node:path";
 import { fileURLToPath } from "node:url";
 import { buildSync } from "esbuild";
+import { atomicWriteFileSync } from "./atomic-write-file";
 import {
   HYPERFRAME_RUNTIME_ARTIFACTS,
   HYPERFRAME_RUNTIME_CONTRACT,
@@ -47,9 +48,9 @@ const manifest = {
 };
 
 mkdirSync(distDir, { recursive: true });
-writeFileSync(iifePath, runtimeSource, "utf8");
-writeFileSync(esmPath, esmSource, "utf8");
-writeFileSync(manifestPath, `${JSON.stringify(manifest, null, 2)}\n`, "utf8");
+atomicWriteFileSync(iifePath, runtimeSource, "utf8");
+atomicWriteFileSync(esmPath, esmSource, "utf8");
+atomicWriteFileSync(manifestPath, `${JSON.stringify(manifest, null, 2)}\n`, "utf8");
 
 // ── Generate src/generated/runtime-inline.ts ──────────────────────────────
 // This file is compiled by tsc into dist/ and provides the production-safe
@@ -59,7 +60,7 @@ const generatedDir = resolve(thisDir, "../src/generated");
 mkdirSync(generatedDir, { recursive: true });
 const inlineModulePath = resolve(generatedDir, "runtime-inline.ts");
 const escapedSource = JSON.stringify(runtimeSourceRaw);
-writeFileSync(
+atomicWriteFileSync(
   inlineModulePath,
   [
     "// AUTO-GENERATED by scripts/build-hyperframes-runtime-artifact.ts — do not edit",
diff --git a/scripts/publish-workflow.test.mjs b/scripts/publish-workflow.test.mjs
index 051543daff..040812b20a 100644
--- a/scripts/publish-workflow.test.mjs
+++ b/scripts/publish-workflow.test.mjs
@@ -7,6 +7,7 @@ import test from "node:test";
 import { parse } from "yaml";
 
 const workflow = readFileSync(new URL("../.github/workflows/publish.yml", import.meta.url), "utf8");
+const rootPackage = JSON.parse(readFileSync(new URL("../package.json", import.meta.url), "utf8"));
 const config = parse(workflow);
 const publish = config.jobs.publish;
 const checkout = publish.steps.find((step) => step.uses?.startsWith("actions/checkout@"));
@@ -66,6 +67,32 @@ test("the executable checkout guard cannot be conditionally disabled", () => {
   );
 });
 
+test("the release build orders generated artifacts before their consumers", () => {
+  const packagesByStage = rootPackage.scripts.build.split(/\s*&&\s*/).map((stage) => {
+    const filter = stage.match(/@hyperframes\/(?:\{([^}]+)\}|([a-z0-9-]+))/);
+    const packages = filter?.[1]?.split(",") ?? [filter?.[2]].filter(Boolean);
+    return new Set(packages);
+  });
+  const firstStageWith = (packageName) =>
+    packagesByStage.findIndex((packages) => packages.has(packageName));
+
+  const coreIndex = firstStageWith("core");
+  const producerIndex = firstStageWith("producer");
+  const cloudRunIndex = firstStageWith("gcp-cloud-run");
+
+  assert.notEqual(coreIndex, -1, "root build must include Core");
+  assert.notEqual(producerIndex, -1, "root build must include Producer");
+  assert.notEqual(cloudRunIndex, -1, "root build must include GCP Cloud Run");
+  assert.ok(
+    packagesByStage.slice(coreIndex + 1).every((packages) => !packages.has("core")),
+    "Core rewrites generated source and must not rebuild in a later parallel group",
+  );
+  assert.ok(
+    producerIndex < cloudRunIndex,
+    "Producer declaration emit must finish before GCP Cloud Run consumes it",
+  );
+});
+
 test("stable release tag recovery is idempotent and immutable", () => {
   assert.ok(createReleaseTag);
   assert.equal(createReleaseTag.if, "github.event_name == 'pull_request'");