diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c9a8e809d1..384e54d303 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -360,8 +360,8 @@ jobs:
       - name: Stage current portable build task cache
         shell: bash
         run: |
-          npm run --silent test:prepare -- --dry=json |
-            node scripts/ci/portable-build-cache.mjs snapshot
+          # A new Turbo dry run can evict the entries this build just used.
+          node scripts/ci/portable-build-cache.mjs snapshot < .cache/ci-build-plan.json
       - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
         with:
           name: rea-build-cache
diff --git a/docs/readme/README_fr.md b/docs/readme/README_fr.md
index b797309b42..82e9634597 100644
--- a/docs/readme/README_fr.md
+++ b/docs/readme/README_fr.md
@@ -2,6 +2,7 @@
 
 [English](../../README.md) · [简体中文](README_zh.md) · [繁體中文](README_zh-TW.md) · [日本語](README_ja.md) · [한국어](README_ko.md) · [Türkçe](README_tr.md) · [Русский](README_ru.md) · [Tiếng Việt](README_vi.md) · [ไทย](README_th.md) · [Deutsch](README_de.md) · [Español](README_es.md) · **Français** · [Українська](README_uk.md) · [Polski](README_pl.md) · [Português (Brasil)](README_pt-BR.md) · [العربية](README_ar.md) · [فارسی](README_fa.md) · [Bahasa Indonesia](README_id.md) · [Italiano](README_it.md)
 · [Ελληνικά](README_el.md) · [മലയാളം](README_ml.md)
+
 # REA : rétro-ingénierie de tout
 
 ### Un seul MCP pour la rétro-ingénierie des binaires, des applications et du comportement à l'exécution.
diff --git a/docs/testing.md b/docs/testing.md
index 6fe29071b7..da96fd889e 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -534,9 +534,14 @@ that generator's entry. Native outputs are not stored in this cache.
 
 Native package jobs, the Windows curated lane, and the Apple artifact lane reuse
 the same workflow's Turbo cache for portable compiled JavaScript, skills, and
-catalogs. The producer stages only the completed `test:prepare` task hashes into
-`.cache/ci-build-cache/`, preserving their archives, metadata, and available manifests.
-Missing required entries fail publication; older cross-run entries stay in the
+catalogs. The key parser retains the validated `test:prepare` task identities in
+`.cache/ci-build-plan.json`; staging reads this plan without starting another
+Turbo run that could evict cache entries. The producer stages matching archives,
+metadata, and available manifests into `.cache/ci-build-cache/`.
+`portable-build-cache.json` records availability per task. Evicted or partially
+missing entries are omitted as whole entries, and consumers rebuild cache misses,
+including when every entry is unavailable. Malformed plans, non-file entries,
+and I/O errors other than disappearance still fail publication. Older cross-run entries stay in the
 original cache. The Windows lane relies on the Linux static job for typechecking. They retain the normal build and prepack
 commands, which restore matching outputs or rebuild on a cache miss. Native
 artifacts, dependency installs, package archives, and runtime verification remain
diff --git a/scripts/ci/portable-build-cache.mjs b/scripts/ci/portable-build-cache.mjs
index 9a029d9e70..789ff32df9 100644
--- a/scripts/ci/portable-build-cache.mjs
+++ b/scripts/ci/portable-build-cache.mjs
@@ -1,10 +1,11 @@
 import { createHash } from "node:crypto";
 import { readFileSync } from "node:fs";
-import { copyFile, lstat, mkdir, rm } from "node:fs/promises";
+import { copyFile, lstat, mkdir, rm, writeFile } from "node:fs/promises";
 import { join } from "node:path";
 import { z } from "zod";
 
 const output = ".cache/ci-build-cache";
+const plan = ".cache/ci-build-plan.json";
 
 function readTasks() {
   const { tasks } = z
@@ -29,37 +30,93 @@ function readTasks() {
   return tasks;
 }
 
+async function copyEntry(hash) {
+  const entries = [];
+  for (const suffix of [".tar.zst", "-meta.json", "-manifest.json"]) {
+    const name = `${hash}${suffix}`;
+    const source = join(".turbo/cache", name);
+    const entry = await lstat(source).catch((error) => {
+      // Eviction can remove a cache hit even during the successful build.
+      // Manifests are also optional in supported local cache entries.
+      if (error.code === "ENOENT") return undefined;
+      throw error;
+    });
+    if (!entry) continue;
+    if (!entry.isFile())
+      throw new Error(
+        `Portable build cache entry must be a regular file: ${source}`,
+      );
+    entries.push({ suffix, name, source, size: entry.size });
+  }
+  // Publish whole reusable entries only. Consumers rebuild missing tasks.
+  if (
+    ![".tar.zst", "-meta.json"].every((suffix) =>
+      entries.some((entry) => entry.suffix === suffix),
+    )
+  )
+    return undefined;
+  const copied = [];
+  let missing = false;
+  for (const entry of entries) {
+    try {
+      await copyFile(entry.source, join(output, entry.name));
+      copied.push(entry);
+    } catch (error) {
+      if (error.code !== "ENOENT") throw error;
+      if (entry.suffix === "-manifest.json") continue;
+      missing = true;
+      break;
+    }
+  }
+  if (missing) {
+    for (const entry of copied) await rm(join(output, entry.name));
+    return undefined;
+  }
+  return {
+    files: copied.length,
+    bytes: copied.reduce((sum, entry) => sum + entry.size, 0),
+  };
+}
+
 async function snapshot(tasks) {
   await mkdir(output, { recursive: true });
   let files = 0;
   let bytes = 0;
+  const available = new Set();
   try {
     for (const hash of new Set(tasks.map((task) => task.hash))) {
-      for (const suffix of [".tar.zst", "-meta.json", "-manifest.json"]) {
-        const name = `${hash}${suffix}`;
-        const source = join(".turbo/cache", name);
-        const entry = await lstat(source).catch((error) => {
-          // Manifests are not present in every supported local cache entry.
-          if (suffix === "-manifest.json" && error.code === "ENOENT")
-            return undefined;
-          throw error;
-        });
-        if (!entry) continue;
-        if (!entry.isFile())
-          throw new Error(
-            `Portable build cache entry must be a regular file: ${source}`,
-          );
-        await copyFile(source, join(output, name));
-        files++;
-        bytes += entry.size;
-      }
+      const entry = await copyEntry(hash);
+      if (!entry) continue;
+      available.add(hash);
+      files += entry.files;
+      bytes += entry.bytes;
     }
+    // A fully evicted cache still has an explicit artifact and coverage record;
+    // required build outputs and downstream verification remain separate gates.
+    const manifest = `${JSON.stringify({
+      version: 1,
+      tasks: tasks.map((task) => ({
+        ...task,
+        available: available.has(task.hash),
+      })),
+    })}\n`;
+    await writeFile(join(output, "portable-build-cache.json"), manifest);
+    files++;
+    bytes += Buffer.byteLength(manifest);
   } catch (error) {
     await rm(output, { recursive: true, force: true });
     throw error;
   }
   console.log(
-    JSON.stringify({ tasks: tasks.length, files, bytes, path: output }),
+    JSON.stringify({
+      tasks: tasks.length,
+      files,
+      bytes,
+      path: output,
+      missing_tasks: tasks
+        .filter((task) => !available.has(task.hash))
+        .map((task) => task.taskId),
+    }),
   );
 }
 
@@ -68,9 +125,10 @@ if (extra.length || !["key", "snapshot"].includes(mode))
   throw new Error(
     "Usage: portable-build-cache.mjs key|snapshot < turbo-dry-plan.json",
   );
-// Remove any earlier snapshot before parsing: a failed second invocation must
-// never leave an old successful artifact eligible for upload.
+// Invalidate this mode's previous result before parsing its input. Failed
+// validation must not leave stale plans or snapshots for downstream reuse.
 if (mode === "snapshot") await rm(output, { recursive: true, force: true });
+else await rm(plan, { force: true });
 const tasks = readTasks();
 if (mode === "key") {
   const prefix = z
@@ -80,6 +138,10 @@ if (mode === "key") {
     .parse(process.env.BUILD_CACHE_PREFIX);
   const hashes = tasks.map(({ taskId, hash }) => `${taskId}:${hash}`).sort();
   const digest = createHash("sha256").update(hashes.join("\n")).digest("hex");
+  // Retain only validated identities for the later snapshot. Running Turbo
+  // again after the build can evict cache entries before they are copied.
+  await mkdir(".cache", { recursive: true });
+  await writeFile(plan, `${JSON.stringify({ tasks })}\n`);
   console.log(`key=${prefix}-${digest}\nprefix=${prefix}-`);
 } else {
   await snapshot(tasks);
diff --git a/tests/boundary/filesystem/ciPortableBuildCache.test.ts b/tests/boundary/filesystem/ciPortableBuildCache.test.ts
index a677d2aa0e..c059818b61 100644
--- a/tests/boundary/filesystem/ciPortableBuildCache.test.ts
+++ b/tests/boundary/filesystem/ciPortableBuildCache.test.ts
@@ -1,6 +1,7 @@
 import { spawnSync } from "node:child_process";
-import { createHash } from "node:crypto";
+import { createHash, randomBytes } from "node:crypto";
 import {
+  cp,
   mkdir,
   readFile,
   readdir,
@@ -9,8 +10,10 @@ import {
   writeFile,
 } from "node:fs/promises";
 import { join } from "node:path";
-import { fileURLToPath } from "node:url";
+import { fileURLToPath, pathToFileURL } from "node:url";
 import { expect, it } from "vitest";
+import { parse } from "yaml";
+import { z } from "zod";
 import { createTestTempDirectory } from "../../fixtures/temporaryDirectory.js";
 
 const script = fileURLToPath(
@@ -21,13 +24,19 @@ const second = { taskId: "artifacts:skills", hash: "fedcba9876543210" };
 const plan = { tasks: [first, second] };
 const prefix = "rea-portable-build-v2-Linux-X64-toolchain";
 const output = ".cache/ci-build-cache";
+const manifestName = "portable-build-cache.json";
 
-function run(root: string, mode: "key" | "snapshot", input: unknown = plan) {
+function run(
+  root: string,
+  mode: "key" | "snapshot",
+  input: unknown = plan,
+  environment: NodeJS.ProcessEnv = {},
+) {
   const result = spawnSync(process.execPath, [script, mode], {
     cwd: root,
     input: typeof input === "string" ? input : JSON.stringify(input),
     encoding: "utf8",
-    env: { ...process.env, BUILD_CACHE_PREFIX: prefix },
+    env: { ...process.env, BUILD_CACHE_PREFIX: prefix, ...environment },
   });
   expect(result.error).toBeUndefined();
   return result;
@@ -61,6 +70,12 @@ async function inventory(root: string, path: string) {
   );
 }
 
+const payload = async (root: string) =>
+  (await inventory(root, output)).filter(([name]) => name !== manifestName);
+
+const coverage = async (root: string) =>
+  JSON.parse(await readFile(join(root, output, manifestName), "utf8"));
+
 it("publishes only current task companions without changing the source cache or retaining old snapshots", async () => {
   const root = await fixture();
   await entry(root, first.hash);
@@ -72,14 +87,19 @@ it("publishes only current task companions without changing the source cache or
   const current = before.filter(
     ([name]) => name?.startsWith(first.hash) || name?.startsWith(second.hash),
   );
-  expect(await inventory(root, output)).toEqual(current);
+  expect(await payload(root)).toEqual(current);
   expect(JSON.parse(result.stdout)).toMatchObject({
     tasks: 2,
-    files: 5,
+    files: 6,
     path: output,
+    missing_tasks: [],
+  });
+  expect(await coverage(root)).toEqual({
+    version: 1,
+    tasks: plan.tasks.map((task) => ({ ...task, available: true })),
   });
   expect(run(root, "snapshot", { tasks: [second] }).status).toBe(0);
-  expect(await inventory(root, output)).toEqual(
+  expect(await payload(root)).toEqual(
     before.filter(([name]) => name?.startsWith(second.hash)),
   );
   expect(await inventory(root, ".turbo/cache")).toEqual(before);
@@ -96,9 +116,15 @@ it("retains existing cross-run keys independent of plan order and invalidates ch
     )
     .digest("hex");
   const expected = `key=${prefix}-${digest}\nprefix=${prefix}-\n`;
-  const result = run(root, "key");
+  const result = run(root, "key", {
+    tasks: plan.tasks.map((task) => ({ ...task, command: "not retained" })),
+    environmentVariables: { passthrough: ["not retained"] },
+  });
   expect(result.status, result.stderr).toBe(0);
   expect(result.stdout).toBe(expected);
+  expect(
+    JSON.parse(await readFile(join(root, ".cache/ci-build-plan.json"), "utf8")),
+  ).toEqual(plan);
   expect(run(root, "key", { tasks: [second, first] }).stdout).toBe(expected);
   const changed = run(root, "key", {
     tasks: [first, { ...second, hash: "aaaaaaaaaaaaaaaa" }],
@@ -120,6 +146,10 @@ it("rejects malformed or ambiguous plans in both commands and removes stale publ
   ]) {
     await mkdir(join(root, output), { recursive: true });
     await writeFile(join(root, output, "old-success"), "stale");
+    await writeFile(
+      join(root, ".cache/ci-build-plan.json"),
+      JSON.stringify(plan),
+    );
     for (const mode of ["key", "snapshot"] as const) {
       const result = run(root, mode, invalid);
       expect(result.status, result.stderr).not.toBe(0);
@@ -128,21 +158,58 @@ it("rejects malformed or ambiguous plans in both commands and removes stale publ
     await expect(readdir(join(root, output))).rejects.toMatchObject({
       code: "ENOENT",
     });
+    await expect(
+      readFile(join(root, ".cache/ci-build-plan.json")),
+    ).rejects.toMatchObject({
+      code: "ENOENT",
+    });
   }
 });
 
-it("fails publication on a cold cache, missing companions or non-file entries, including after a partial copy", async () => {
+it("records cold caches and omits whole entries with missing required companions", async () => {
   const root = await fixture();
-  expect(run(root, "snapshot").status).not.toBe(0);
-  await expect(readdir(join(root, output))).rejects.toMatchObject({
-    code: "ENOENT",
+  const cold = run(root, "snapshot");
+  expect(cold.status, cold.stderr).toBe(0);
+  expect(JSON.parse(cold.stdout)).toMatchObject({
+    files: 1,
+    missing_tasks: plan.tasks.map((task) => task.taskId),
   });
+  expect(await payload(root)).toEqual([]);
+  expect(await coverage(root)).toEqual({
+    version: 1,
+    tasks: plan.tasks.map((task) => ({ ...task, available: false })),
+  });
+  await entry(root, first.hash);
+  for (const suffix of [".tar.zst", "-meta.json"]) {
+    await entry(root, second.hash);
+    await rm(join(root, ".turbo/cache", `${second.hash}${suffix}`));
+    const result = run(root, "snapshot");
+    expect(result.status, result.stderr).toBe(0);
+    expect(JSON.parse(result.stdout)).toMatchObject({
+      files: 4,
+      missing_tasks: [second.taskId],
+    });
+    expect(
+      (await payload(root)).every(([name]) => name?.startsWith(first.hash)),
+    ).toBe(true);
+    expect(await coverage(root)).toEqual({
+      version: 1,
+      tasks: [
+        { ...first, available: true },
+        { ...second, available: false },
+      ],
+    });
+  }
+});
+
+it("rejects non-file cache companions and cleans up already copied entries", async () => {
+  const root = await fixture();
   await entry(root, first.hash);
   for (const suffix of [".tar.zst", "-meta.json", "-manifest.json"]) {
     await entry(root, second.hash);
     const path = join(root, ".turbo/cache", `${second.hash}${suffix}`);
     await rm(path);
-    if (suffix === "-manifest.json") await mkdir(path);
+    await mkdir(path);
     const result = run(root, "snapshot");
     expect(result.status, result.stderr).not.toBe(0);
     await expect(readdir(join(root, output))).rejects.toMatchObject({
@@ -152,6 +219,59 @@ it("fails publication on a cold cache, missing companions or non-file entries, i
   }
 });
 
+it.each([
+  { suffix: "-meta.json", code: "ENOENT" },
+  { suffix: "-manifest.json", code: "ENOENT" },
+  { suffix: "-meta.json", code: "EACCES" },
+])(
+  "handles $code during $suffix copying without publishing partial entries",
+  async ({ suffix, code }) => {
+    const root = await fixture();
+    await entry(root, first.hash);
+    await entry(root, second.hash);
+    const preload = join(root, "evict-during-copy.mjs");
+    await writeFile(
+      preload,
+      `
+import fs from "node:fs/promises";
+import { syncBuiltinESMExports } from "node:module";
+const copy = fs.copyFile;
+fs.copyFile = async (source, ...args) => {
+  if (source.endsWith(${JSON.stringify(second.hash + suffix)})) {
+    if (${JSON.stringify(code)} === "ENOENT") await fs.unlink(source);
+    else throw Object.assign(new Error("copy denied"), { code: "EACCES" });
+  }
+  return copy(source, ...args);
+};
+syncBuiltinESMExports();
+`,
+    );
+    const result = run(root, "snapshot", plan, {
+      NODE_OPTIONS: `${process.env.NODE_OPTIONS ?? ""} --import=${pathToFileURL(preload).href}`,
+    });
+    if (code === "EACCES") {
+      expect(result.status).not.toBe(0);
+      expect(result.stderr).toContain("EACCES");
+      await expect(readdir(join(root, output))).rejects.toMatchObject({
+        code: "ENOENT",
+      });
+    } else {
+      expect(result.status, result.stderr).toBe(0);
+      const missing = suffix === "-meta.json";
+      expect(JSON.parse(result.stdout).missing_tasks).toEqual(
+        missing ? [second.taskId] : [],
+      );
+      expect(
+        (await payload(root)).filter(([name]) => name?.startsWith(second.hash)),
+      ).toHaveLength(missing ? 0 : 2);
+      expect((await coverage(root)).tasks).toEqual([
+        { ...first, available: true },
+        { ...second, available: !missing },
+      ]);
+    }
+  },
+);
+
 it.skipIf(process.platform === "win32")(
   "rejects symlinked archives and optional manifests without copying their targets",
   async () => {
@@ -174,3 +294,214 @@ it.skipIf(process.platform === "win32")(
     }
   },
 );
+
+async function workflowFixture(historyKiB: number) {
+  const repository = fileURLToPath(new URL("../../../", import.meta.url));
+  const { packageManager } = z
+    .object({ packageManager: z.string() })
+    .parse(
+      JSON.parse(await readFile(join(repository, "package.json"), "utf8")),
+    );
+  const steps = z.array(
+    z.object({
+      id: z.string().optional(),
+      name: z.string().optional(),
+      run: z.string().optional(),
+    }),
+  );
+  const action = z
+    .object({ runs: z.object({ steps }) })
+    .parse(
+      parse(
+        await readFile(
+          join(repository, ".github/actions/portable-build-cache/action.yml"),
+          "utf8",
+        ),
+      ),
+    );
+  const workflow = z
+    .object({ jobs: z.object({ build: z.object({ steps }) }) })
+    .parse(
+      parse(
+        await readFile(join(repository, ".github/workflows/ci.yml"), "utf8"),
+      ),
+    );
+  const planCommand = action.runs.steps.find((step) => step.id === "plan")?.run;
+  const stageCommand = workflow.jobs.build.steps.find(
+    (step) => step.name === "Stage current portable build task cache",
+  )?.run;
+  expect(planCommand).toBeTypeOf("string");
+  expect(stageCommand).toBeTypeOf("string");
+  const root = await fixture();
+  await symlink(
+    join(repository, "node_modules"),
+    join(root, "node_modules"),
+    "junction",
+  );
+  await mkdir(join(root, "scripts/ci"), { recursive: true });
+  await writeFile(
+    join(root, "scripts/ci/portable-build-cache.mjs"),
+    await readFile(script),
+  );
+  await writeFile(join(root, "input.bin"), randomBytes(192 * 1024));
+  await writeFile(
+    join(root, "package.json"),
+    JSON.stringify({
+      name: "portable-cache-workflow-fixture",
+      version: "1.0.0",
+      private: true,
+      packageManager,
+      scripts: {
+        "test:prepare": "turbo run build",
+        "seed:prepare": "turbo run seed",
+        "metadata:check": "node -e \"console.log('validated')\"",
+        build: "node produce.mjs build",
+        seed: "node produce.mjs seed",
+      },
+    }),
+  );
+  await writeFile(
+    join(root, "package-lock.json"),
+    JSON.stringify({
+      name: "portable-cache-workflow-fixture",
+      version: "1.0.0",
+      lockfileVersion: 3,
+      packages: {
+        "": { name: "portable-cache-workflow-fixture", version: "1.0.0" },
+      },
+    }),
+  );
+  await writeFile(
+    join(root, "produce.mjs"),
+    `
+import { mkdir, readFile, writeFile } from "node:fs/promises";
+const name = process.argv[2];
+await mkdir("out", { recursive: true });
+const bytes = await readFile("input.bin");
+await writeFile("out/" + name + ".bin", bytes.subarray(0, (name === "seed" ? ${historyKiB} : 64) * 1024));
+`,
+  );
+  await writeFile(
+    join(root, "turbo.json"),
+    JSON.stringify({
+      cacheDir: ".turbo/cache",
+      cacheMaxSize: "0.125MB",
+      tasks: {
+        "metadata:check": { outputs: [] },
+        build: { dependsOn: ["metadata:check"], outputs: ["out/build.bin"] },
+        seed: { dependsOn: ["metadata:check"], outputs: ["out/seed.bin"] },
+      },
+    }),
+  );
+  await writeFile(
+    join(root, ".gitignore"),
+    "node_modules/\n.turbo/\n.cache/\nout/\n",
+  );
+  const execute = (command: string | undefined, expectedStatus = 0) => {
+    if (command === undefined) throw new Error("Missing workflow command");
+    const result = spawnSync(
+      "bash",
+      ["--noprofile", "--norc", "-e", "-o", "pipefail", "-c", command],
+      {
+        cwd: root,
+        encoding: "utf8",
+        timeout: 30_000,
+        env: {
+          ...process.env,
+          BUILD_CACHE_PREFIX: prefix,
+          GITHUB_OUTPUT: join(root, ".turbo/action-output"),
+          TURBO_CACHE_DIR: ".turbo/cache",
+          TURBO_CACHE_MAX_SIZE: "0.125MB",
+          TURBO_CACHE_MAX_AGE: "0",
+          TURBO_TELEMETRY_DISABLED: "1",
+        },
+      },
+    );
+    expect(result.error).toBeUndefined();
+    expect(result.status, result.stdout + result.stderr).toBe(expectedStatus);
+    return expectedStatus === 0 ? result.stdout : result.stdout + result.stderr;
+  };
+  return { root, planCommand, stageCommand, execute };
+}
+
+it.skipIf(process.platform === "win32").each([
+  { historyKiB: 96, evictAll: false },
+  { historyKiB: 192, evictAll: false },
+  { historyKiB: 96, evictAll: true },
+])(
+  "stages and restores current build entries through the real workflow (history=$historyKiB KiB, evictAll=$evictAll)",
+  async ({ historyKiB, evictAll }) => {
+    const { root, planCommand, stageCommand, execute } =
+      await workflowFixture(historyKiB);
+    execute(planCommand);
+    // Exercise eviction at build startup, after building, and complete cache
+    // loss. All are cache misses; successful build artifacts remain required.
+    execute("npm run --silent seed:prepare");
+    const prepared = execute("npm run --silent test:prepare");
+    expect(prepared).toContain("2 successful, 2 total");
+    if (historyKiB === 96)
+      expect(prepared).toContain("Cached:    1 cached, 2 total");
+    const artifact = await readFile(join(root, "out/build.bin"));
+    if (evictAll)
+      execute(
+        "TURBO_CACHE_MAX_SIZE=1B npm run --silent test:prepare -- --dry=json > /dev/null",
+      );
+    const staged = JSON.parse(execute(stageCommand));
+    const index = z
+      .object({
+        version: z.literal(1),
+        tasks: z.array(
+          z.object({
+            taskId: z.string(),
+            hash: z.string(),
+            available: z.boolean(),
+          }),
+        ),
+      })
+      .parse(await coverage(root));
+    const identities = JSON.parse(
+      await readFile(join(root, ".cache/ci-build-plan.json"), "utf8"),
+    );
+    expect(
+      index.tasks.map(({ available: _available, ...task }) => task),
+    ).toEqual(identities.tasks);
+    const hits = index.tasks.filter((task) => task.available).length;
+    expect(staged).toMatchObject({
+      tasks: 2,
+      files: 1 + hits * 3,
+      missing_tasks: index.tasks
+        .filter((task) => !task.available)
+        .map((task) => task.taskId),
+    });
+    if (evictAll) expect(hits).toBe(0);
+    const remaining = await readdir(join(root, ".turbo/cache"));
+    for (const task of index.tasks)
+      expect(task.available).toBe(
+        [".tar.zst", "-meta.json"].every((suffix) =>
+          remaining.includes(`${task.hash}${suffix}`),
+        ),
+      );
+    await rm(join(root, ".turbo/cache"), { recursive: true });
+    await cp(join(root, output), join(root, ".turbo/cache"), {
+      recursive: true,
+    });
+    await rm(join(root, "out"), { recursive: true });
+    const restored = execute("npm run --silent test:prepare");
+    expect(restored).toContain(`Cached:    ${hits} cached, 2 total`);
+    expect(await readFile(join(root, "out/build.bin"))).toEqual(artifact);
+    await expect(readFile(join(root, "out/seed.bin"))).rejects.toMatchObject({
+      code: "ENOENT",
+    });
+    execute(planCommand);
+    execute("npm run --silent test:prepare");
+    expect(JSON.parse(execute(stageCommand))).toMatchObject({
+      tasks: 2,
+      files: 7,
+      missing_tasks: [],
+    });
+    if (evictAll) {
+      await writeFile(join(root, "produce.mjs"), "process.exitCode = 47;\n");
+      expect(execute("npm run --silent test:prepare", 47)).toContain("(47)");
+    }
+  },
+);
diff --git a/tests/boundary/filesystem/ciRequiredLanes.test.ts b/tests/boundary/filesystem/ciRequiredLanes.test.ts
index 139ebfe7b9..457d532560 100644
--- a/tests/boundary/filesystem/ciRequiredLanes.test.ts
+++ b/tests/boundary/filesystem/ciRequiredLanes.test.ts
@@ -200,7 +200,7 @@ it("binds provider build reuse to the current run while keeping standalone dispa
   expect(stage).toBeGreaterThan(prepare);
   expect(upload).toBeGreaterThan(stage);
   expect(buildSteps[stage]?.run).toContain(
-    "npm run --silent test:prepare -- --dry=json |",
+    "node scripts/ci/portable-build-cache.mjs snapshot < .cache/ci-build-plan.json",
   );
   expect(buildSteps[stage]?.if).toBeUndefined();
   expect(buildSteps[stage]?.shell).toBe("bash");
diff --git a/tests/boundary/process/electronLaunchRejections.test.ts b/tests/boundary/process/electronLaunchRejections.test.ts
index c2f32e5c85..7c4b0c47f6 100644
--- a/tests/boundary/process/electronLaunchRejections.test.ts
+++ b/tests/boundary/process/electronLaunchRejections.test.ts
@@ -2,6 +2,7 @@ import { chmod, mkdir, writeFile } from "node:fs/promises";
 import { join } from "node:path";
 
 import { expect, vi } from "vitest";
+import type { AnalysisErrorProjection } from "../../../src/domain/analysisErrorProjection.js";
 
 import { createTestTempDirectory } from "../../fixtures/temporaryDirectory.js";
 import {
@@ -12,6 +13,7 @@ import {
 const script = `
 import { PlaywrightElectronActiveProvider } from "./dist/browser/PlaywrightElectronActiveProvider.js";
 import { electronActiveObservationInputSchema } from "./dist/domain/javascript/electronActiveObservation.js";
+import { projectAnalysisError } from "./dist/domain/analysisErrorProjection.js";
 
 const [scenario, executable, root] = JSON.parse(process.argv[1]);
 let observedRejections = 0;
@@ -114,11 +116,8 @@ console.log(JSON.stringify({
   during,
   after: process.listenerCount("unhandledRejection"),
   observedRejections,
-  reasons: results.map((result) => result.ok ? null : result.error.reason ?? null),
+  errors: results.map((result) => result.ok ? null : projectAnalysisError(result.error)),
   ok: results.map((result) => result.ok),
-  causeReasons: results.map((result) => result.ok ? null : result.error.cause?.reason ?? null),
-  cleanupResources: results.map((result) => result.ok ? null : result.error.cleanupResources ?? null),
-  causes: results.map((result) => result.ok ? null : String(result.error.cause?.message).split("\\n")[0]),
 }));
 `;
 
@@ -131,11 +130,8 @@ type Outcome = {
   readonly during: number;
   readonly after: number;
   readonly ok: readonly boolean[];
-  readonly causes: readonly (string | null)[];
+  readonly errors: readonly (AnalysisErrorProjection | null)[];
   readonly observedRejections: number;
-  readonly reasons: readonly (string | null)[];
-  readonly causeReasons: readonly (string | null)[];
-  readonly cleanupResources: readonly (readonly string[] | null)[];
 };
 
 const run = async (
@@ -176,7 +172,17 @@ processTest(
       during: outcome(result).before + 1,
       after: outcome(result).before,
       ok: [false],
-      causes: ["electron.launch: Process failed to launch!"],
+      errors: [
+        {
+          details: {
+            diagnostics: {
+              message: expect.stringContaining(
+                "electron.launch: Process failed to launch!",
+              ),
+            },
+          },
+        },
+      ],
     });
   },
 );
@@ -198,7 +204,17 @@ processTest.skipIf(process.platform === "win32")(
     expect(result.exitCode, result.stderr).toBe(0);
     expect(outcome(result)).toMatchObject({
       ok: [false],
-      causes: ["electron.launch: Process failed to launch!"],
+      errors: [
+        {
+          details: {
+            diagnostics: {
+              message: expect.stringContaining(
+                "electron.launch: Process failed to launch!",
+              ),
+            },
+          },
+        },
+      ],
     });
     expect(outcome(result).after).toBe(outcome(result).before);
   },
@@ -228,7 +244,17 @@ processTest(
     expect(outcome(result)).toMatchObject({
       observedRejections: 1,
       ok: [false],
-      causes: ["electron.launch: Process failed to launch!"],
+      errors: [
+        {
+          details: {
+            diagnostics: {
+              message: expect.stringContaining(
+                "electron.launch: Process failed to launch!",
+              ),
+            },
+          },
+        },
+      ],
     });
   },
 );
@@ -303,21 +329,37 @@ processTest(
     expect(observed.after).toBe(observed.before);
     expect(observed.observedRejections).toBe(3);
     expect(observed.ok).toEqual([false, false, false, false, false]);
-    expect(observed.causes[0]).toBe("electron.launch: alpha failed");
-    expect(observed.reasons).toEqual([
-      null,
-      "cleanup_failed",
-      "cleanup_failed",
-      "cleanup_failed",
-      "cleanup_failed",
-    ]);
-    expect(observed.causeReasons).toEqual([
-      null,
-      ...Array.from({ length: 4 }, () => "process_ownership_unavailable"),
-    ]);
-    expect(observed.cleanupResources).toEqual([
-      [],
-      ...Array.from({ length: 4 }, () => ["owned_process_group"]),
+    expect(observed.errors).toMatchObject([
+      {
+        details: {
+          diagnostics: {
+            message: expect.stringContaining("electron.launch: alpha failed"),
+          },
+        },
+      },
+      ...Array.from({ length: 4 }, () => ({
+        code: "cleanup_incomplete",
+        details: {
+          cleanup: "incomplete",
+          resources: ["owned_process_group"],
+          diagnostics: {
+            primary_error: {
+              code: "unreadable_output",
+              details: {
+                reason: "process_ownership_unavailable",
+              },
+            },
+            cleanup_error: {
+              code: "cleanup_incomplete",
+              details: {
+                reason: "cleanup_failed",
+                cleanup: "incomplete",
+                resources: ["owned_process_group"],
+              },
+            },
+          },
+        },
+      })),
     ]);
   },
 );