diff --git a/.gstack/pregate.json b/.gstack/pregate.json
index 69573040e..f9cb2832c 100644
--- a/.gstack/pregate.json
+++ b/.gstack/pregate.json
@@ -1,6 +1,7 @@
 {
   "$schema": "https://github.com/garrytan/gstack/docs/pregate.md#pregate-v1",
   "runner": "bun test {files}",
+  "remote_gate": "bash scripts/ubicloud/pregate-remote.sh",
   "dependencies": {
     ".github/workflows/**": ["test/pregate-selection.test.ts", "test/free-tests-workflow-wiring.test.ts"],
     "scripts/gen-ship-goldens.ts": ["test/host-config.test.ts"],
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ac4418ce4..0e67cb423 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,26 @@
 # Changelog
 
+## [1.91.132.0] - 2026-10-18
+
+**On a machine under 8 cores, `gstack-pregate` clears its test tier on one Ubicloud VM in about 7 minutes for about $0.06, instead of running locally for an hour.** gstack's own `.gstack/pregate.json` now declares a remote gate, so a small machine records the local test tier as a `requires-remote` obligation and `gstack-pregate --stage tests --remote --spend-cap 2 --timeout 2700 --allow-repo-commands` clears it. All 1,280 free test files ran in 404 s (create 24 s, setup 72 s, tests 250 s) for $0.06; the same 798-file selection took 3,550 s locally on 4 cores. `gstack-next-version` also fetches open PRs' VERSION claims in parallel (8 PRs: 4,160 ms before, about 0.5 s now) and says so when it could not read one.
+
+### Added
+- **`scripts/ubicloud/pregate-remote.sh`, gstack's remote gate.** With `UBICLOUD_API_KEY` it runs the selected files on one VM with `bun run test:ubicloud`'s environment, checks the tree and the planned file set on the VM before any test runs, and reports `PREGATE_REMOTE: tree=… tests=… failed=… spent=…` from billed minutes. Without a key it runs the same files locally in parallel shards and prints `backend=local (N cores; not the CI environment)`.
+  - The spend cap buys the wall time at the size's list price (at most 45 minutes); a cap that cannot buy 20 minutes refuses before any VM exists.
+  - It finishes before pregate's own `--timeout`: 120 s are reserved for teardown, and a deadline too short to be useful refuses up front.
+  - At create time it prints the VM name and the exact `bash scripts/ubicloud/ubi-runner.sh down <name>` line.
+  - Paid test files in a selection are named and left to the paid PR gate; a paid-only selection reports `tests=0`, which never clears.
+  - Every refusal starts with a `PREGATE_REMOTE_*` reason code; the table is in docs/pregate.md#remote-gate.
+- **`test-free-shards.ts --files-from <path>`** plans exactly the listed files. Unknown paths, an empty list and malformed or repeated lines are rejected before planning.
+
+### Changed
+- **`gstack-next-version` fetches claims concurrently** (up to 10, 15 s each) and sorts its output by PR number. A fetch that times out or fails is listed in `unknown_claims`, the JSON says `complete: false`, and the pick is marked provisional on stdout and stderr. The fork/path hint appears only for HTTP 404.
+- **`gstack-restamp` in claim-at-open mode reports an incomplete claim queue as `claims: incomplete`**, naming the unknown PRs, instead of `read`.
+
+### If you…
+- **…run `gstack-pregate` on a machine under 8 cores in this repo:** clear the test tier with `gstack-pregate --stage tests --remote --spend-cap 2 --timeout 2700 --allow-repo-commands`. Keyless works too but is practical only for small selections (98 files took 103 s on 4 cores).
+- **…see `complete: false` from `gstack-next-version`:** rerun it before stamping; the slot may collide.
+
 ## [1.91.131.0] - 2026-10-18
 
 **`gstack-pregate` finds the tests for Python files, and a missing `node_modules` no longer reads as "stale generated files".** In a Python repo, the `lanes` check failed almost every touched `.py` file with `PREGATE_NO_LANE`, because the import graph only parsed JavaScript and TypeScript. In a FastAPI service with about 1,500 non-test modules, Scott Gigante's change (#3201) cut the unmapped count from 1,473 to 780, and most of the rest are migrations and scripts no import reaches. Separately, a fresh checkout without `node_modules` made the pre-gate report `REGEN_STALE` and suggest rerunning the generator, which sent people the wrong way.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 97ae6d51f..0486eee65 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -187,6 +187,7 @@ the new defaults.
 | Run one free test file while repairing | `bun test <file>` | Free, seconds | Never bare `bun test` for the suite |
 | Run full free acceptance before publishing | `bun run test` | Free, a few minutes | Bun 1.4.2 |
 | Run the full free suite from a small machine | `bun run test:ubicloud` | Free suite on a billed 16-vCPU VM, about 5 minutes | `UBICLOUD_API_KEY` |
+| Clear pregate's test tier on a machine under 8 cores ([remote gate](docs/pregate.md#remote-gate)) | `gstack-pregate --stage tests --remote --spend-cap 2 --timeout 2700 --allow-repo-commands` (same command keyed or keyless) | Keyed: one billed 16-vCPU VM, about 7 minutes and $0.06 for the whole free tier, worst case $0.38; keyless: free, local parallel shards, practical for small selections only (98 files took 103 s on 4 cores) | Keyed: `UBICLOUD_API_KEY`; keyless: nothing |
 | Run the curated Windows-safe subset | `bun run test:windows` (CI: six `windows-latest` jobs) | Free | Windows, Git Bash |
 | Refresh the Windows duration seed | `gh workflow run windows-free-tests.yml --ref <branch> -f record_durations=true`, then commit the `free-test-durations-windows` artifact | Free CI runners | Pushed branch, `gh` with workflow rights |
 | Run a native Windows or Dia qualification campaign | `gh workflow run native-qualification.yml --ref <branch> -f mode=<mode>` ([modes](docs/TESTING_INTERNALS.md#windows-free-lane)) | Free CI runners | Pushed branch, `gh` with workflow rights |
diff --git a/VERSION b/VERSION
index a1846f406..731cb0b26 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.91.131.0
+1.91.132.0
diff --git a/agents-digest/gstack-AGENTS.md b/agents-digest/gstack-AGENTS.md
index e0a4e9ee8..9ba3da34d 100644
--- a/agents-digest/gstack-AGENTS.md
+++ b/agents-digest/gstack-AGENTS.md
@@ -1,4 +1,4 @@
-# gstack digest v1.91.131.0 — regenerate/re-copy after upgrading gstack
+# gstack digest v1.91.132.0 — regenerate/re-copy after upgrading gstack
 
 Behavioral rules from gstack (https://github.com/garrytan/gstack), compressed
 for agent hosts without a full skill install. The full skills add workflows,
diff --git a/bin/gstack-next-version b/bin/gstack-next-version
index df5473b6b..483d2c5ca 100755
--- a/bin/gstack-next-version
+++ b/bin/gstack-next-version
@@ -6,7 +6,10 @@
 // slot at the requested bump level, and emits the whole picture as JSON.
 //
 // Contract: util NEVER writes files or mutates state. Pure reader + reporter.
-// /ship consumes the JSON and decides what to do.
+// /ship consumes the JSON and decides what to do. `unknown_claims` lists the
+// open PRs whose VERSION could not be read (a 15 s timeout or a non-404
+// failure): their claims are unknown, so the picked slot may collide, and
+// `complete` is false (a provisional pick, also said on stderr and in warnings).
 //
 // Usage:
 //   gstack-next-version --base <branch> --bump <major|minor|patch|micro> \
@@ -34,7 +37,7 @@
 //       empty, unreadable or malformed
 //   3 — util bug (unexpected exception)
 
-import { execFileSync, spawnSync } from "node:child_process";
+import { execFileSync, spawn, spawnSync } from "node:child_process";
 import { existsSync, readFileSync, readdirSync, statSync } from "node:fs";
 import { homedir } from "node:os";
 import { join, resolve } from "node:path";
@@ -84,10 +87,13 @@ type Output = {
   active_siblings: Sibling[];
   reason: string;
   warnings: string[];
+  unknown_claims: number[];
+  complete: boolean;
 };
 
 const ACTIVE_SIBLING_MAX_AGE_S = 24 * 60 * 60;
 const GH_API_CONCURRENCY = 10;
+const VERSION_FETCH_TIMEOUT_MS = 15000;
 
 // Collision resolution: bump past the highest claimed within the same level.
 // Semantics: if my bump is MINOR and the queue claims 1.7.0.0, I advance to
@@ -117,6 +123,33 @@ function runCommand(cmd: string, args: string[], timeoutMs = 15000): { ok: boole
   };
 }
 
+// Async twin of runCommand for the per-PR VERSION fetches, so GH_API_CONCURRENCY
+// workers really overlap. A fetch past timeoutMs is killed and settles at once
+// as timedOut, without waiting on output pipes a descendant may still hold.
+function runCommandAsync(cmd: string, args: string[], timeoutMs: number): Promise<{ ok: boolean; stdout: string; stderr: string; timedOut: boolean }> {
+  return new Promise((done) => {
+    let stdout = "";
+    let stderr = "";
+    const child = spawn(cmd, args, { stdio: ["ignore", "pipe", "pipe"] });
+    const timer = setTimeout(() => {
+      child.kill("SIGKILL");
+      child.stdout.destroy();
+      child.stderr.destroy();
+      done({ ok: false, stdout, stderr, timedOut: true });
+    }, timeoutMs);
+    child.stdout.on("data", (chunk) => { stdout += chunk; });
+    child.stderr.on("data", (chunk) => { stderr += chunk; });
+    child.on("error", (error) => {
+      clearTimeout(timer);
+      done({ ok: false, stdout, stderr: stderr || String(error), timedOut: false });
+    });
+    child.on("close", (code) => {
+      clearTimeout(timer);
+      done({ ok: code === 0, stdout, stderr, timedOut: false });
+    });
+  });
+}
+
 // VERSION-path resolution for monorepos. Priority: CLI flag > .gstack/version-path
 // at repo root > "VERSION". Pure function; takes the repo root as an argument so
 // tests can drive it with a fixture dir without mocking git.
@@ -181,7 +214,13 @@ function readBaseVersion(base: string, versionPath: string, repoRoot: string, wa
   return v;
 }
 
-async function fetchGithubClaimed(base: string, versionPath: string, excludePR: number | null, warnings: string[]): Promise<{ claimed: ClaimedPR[]; offline: boolean }> {
+async function fetchGithubClaimed(
+  base: string,
+  versionPath: string,
+  excludePR: number | null,
+  warnings: string[],
+  fetchTimeoutMs = VERSION_FETCH_TIMEOUT_MS,
+): Promise<{ claimed: ClaimedPR[]; offline: boolean; unknownClaims: number[] }> {
   const list = runCommand("gh", [
     "pr",
     "list",
@@ -196,7 +235,7 @@ async function fetchGithubClaimed(base: string, versionPath: string, excludePR:
   ]);
   if (!list.ok) {
     warnings.push(`gh pr list failed: ${list.stderr.trim().slice(0, 200)}`);
-    return { claimed: [], offline: true };
+    return { claimed: [], offline: true, unknownClaims: [] };
   }
   let prs: {
     number: number;
@@ -209,7 +248,7 @@ async function fetchGithubClaimed(base: string, versionPath: string, excludePR:
     prs = JSON.parse(list.stdout);
   } catch (e) {
     warnings.push(`gh pr list returned invalid JSON`);
-    return { claimed: [], offline: true };
+    return { claimed: [], offline: true, unknownClaims: [] };
   }
   // Determine our repo owner to filter out fork PRs. `gh api contents?ref=<branch>`
   // resolves to OUR repo regardless of where the PR originated, so fork PRs would
@@ -221,43 +260,56 @@ async function fetchGithubClaimed(base: string, versionPath: string, excludePR:
     : prs
   ).filter((p) => excludePR === null || p.number !== excludePR);
   // Fetch each PR's VERSION at its head in parallel (bounded concurrency).
+  // Workers finish in any order, so claims and warnings are sorted by PR number.
   const results: ClaimedPR[] = [];
+  const prWarnings: { pr: number; text: string }[] = [];
+  const unknownClaims: number[] = [];
   const queue = [...sameRepoPRs];
   const workers = Array.from({ length: Math.min(GH_API_CONCURRENCY, sameRepoPRs.length) }, async () => {
     while (queue.length) {
       const pr = queue.shift();
       if (!pr) return;
+      const warn = (text: string) => prWarnings.push({ pr: pr.number, text: `PR #${pr.number}: ${text}` });
       // gh passes branch name via argv, not shell — safe.
       // encodeURI handles spaces in subproject paths (e.g. "Tinas Second Brain/...")
       // while leaving "/" untouched so the GitHub Contents API gets the path intact.
-      const content = runCommand("gh", [
+      const content = await runCommandAsync("gh", [
         "api",
         `repos/{owner}/{repo}/contents/${encodeURI(versionPath)}?ref=${encodeURIComponent(pr.headRefName)}`,
         "-q",
         ".content",
-      ]);
+      ], fetchTimeoutMs);
+      if (content.timedOut) {
+        unknownClaims.push(pr.number);
+        warn(`VERSION fetch timed out after ${fetchTimeoutMs / 1000} s; claim unknown, the slot may collide; rerun, then ask the coordinator`);
+        continue;
+      }
       if (!content.ok) {
-        warnings.push(
-          `PR #${pr.number}: could not fetch ${versionPath} (fork, private, or wrong path — try --version-path or .gstack/version-path)`,
-        );
+        if (/HTTP 404|Not Found/i.test(content.stderr)) {
+          warn(`could not fetch ${versionPath} (fork, private, or wrong path — try --version-path or .gstack/version-path)`);
+        } else {
+          unknownClaims.push(pr.number);
+          warn(`VERSION fetch failed (${content.stderr.trim().split("\n")[0]?.slice(0, 200) || "no error output"}); claim unknown, the slot may collide; rerun, then ask the coordinator`);
+        }
         continue;
       }
       let versionStr: string;
       try {
         versionStr = extractVersion(Buffer.from(content.stdout.trim(), "base64").toString("utf8"), versionPath);
       } catch {
-        warnings.push(`PR #${pr.number}: VERSION is not valid base64`);
+        warn("VERSION is not valid base64");
         continue;
       }
       if (!parseVersion(versionStr)) {
-        warnings.push(`PR #${pr.number}: VERSION is malformed (${versionStr})`);
+        warn(`VERSION is malformed (${versionStr})`);
         continue;
       }
       results.push({ pr: pr.number, branch: pr.headRefName, version: versionStr, url: pr.url });
     }
   });
   await Promise.all(workers);
-  return { claimed: results, offline: false };
+  warnings.push(...prWarnings.sort((a, b) => a.pr - b.pr).map((w) => w.text));
+  return { claimed: results.sort((a, b) => a.pr - b.pr), offline: false, unknownClaims: unknownClaims.sort((a, b) => a - b) };
 }
 
 async function fetchGitlabClaimed(base: string, versionPath: string, excludePR: number | null, warnings: string[]): Promise<{ claimed: ClaimedPR[]; offline: boolean }> {
@@ -730,8 +782,9 @@ async function main() {
 
   let claimed: ClaimedPR[] = [];
   let offline = false;
+  let unknownClaims: number[] = [];
   if (host === "github") {
-    ({ claimed, offline } = await fetchGithubClaimed(args.base, versionPath, excludePR, warnings));
+    ({ claimed, offline, unknownClaims } = await fetchGithubClaimed(args.base, versionPath, excludePR, warnings));
   } else if (host === "gitlab") {
     ({ claimed, offline } = await fetchGitlabClaimed(args.base, versionPath, excludePR, warnings));
   } else {
@@ -789,6 +842,12 @@ async function main() {
     finalReason = `bumped past active sibling ${fmtVersion(highest, width)}`;
   }
 
+  const complete = unknownClaims.length === 0;
+  if (!complete) {
+    const provisional = `provisional pick: the VERSION claims of PR ${unknownClaims.map((n) => `#${n}`).join(", ")} are unknown, so ${fmtVersion(finalVersion, width)} is not a verified slot and may collide; rerun, then ask the coordinator before stamping`;
+    warnings.push(provisional);
+    console.error(`gstack-next-version: ${provisional}`);
+  }
   const out: Output = {
     version: fmtVersion(finalVersion, width),
     current_version: args.current || baseVersion,
@@ -803,6 +862,8 @@ async function main() {
     active_siblings: activeSiblings,
     reason: finalReason,
     warnings,
+    unknown_claims: unknownClaims,
+    complete,
   };
   process.stdout.write(JSON.stringify(out, null, 2) + "\n");
 }
@@ -811,7 +872,7 @@ async function main() {
 // from lib/version-source so existing importers of this module keep working
 // unchanged.
 export { parseVersion, fmtVersion, bumpVersion, cmpVersion, versionWidth, extractVersion };
-export { pickNextSlot, markActiveSiblings, resolveVersionPath, fetchGitClaimed };
+export { pickNextSlot, markActiveSiblings, resolveVersionPath, fetchGitClaimed, fetchGithubClaimed, VERSION_FETCH_TIMEOUT_MS };
 
 // Only run main() when invoked as a script, not when imported by tests.
 if (import.meta.main) {
diff --git a/docs/pregate.md b/docs/pregate.md
index b988c06ab..da5504dfd 100644
--- a/docs/pregate.md
+++ b/docs/pregate.md
@@ -240,6 +240,62 @@ the supervision above. Close the obligation one of two ways:
   `spent, reserved, unknown`: a gate that prints no `spent=` is `unknown`,
   counted at the cap.
 
+gstack's own example: `.gstack/pregate.json` declares
+`"remote_gate": "bash scripts/ubicloud/pregate-remote.sh"`. With
+`UBICLOUD_API_KEY` set the script runs the selected files on one Ubicloud VM
+with `bun run test:ubicloud`'s environment, refuses before creating the VM when
+the cap cannot buy a 20-minute run at the size's list price (`UBI_SIZE`,
+default `standard-16`), checks the tree and the planned file set on the VM
+before any test runs, and reports `spent=` from billed minutes. Without a key
+it runs the same files locally in parallel shards
+(`test-free-shards.ts --files-from`) and reports `spent=0`, after a
+`backend=local (N cores; not the CI environment)` line. Paid test files in the
+selection (skill-e2e and the other paid globs in `test/helpers/paid-test-set.ts`)
+are named and left to the paid PR gate; a selection of only paid files reports
+`tests=0`, which never clears the obligation. The command is the same either way
+(`--remote` always needs a cap; the keyless path spends nothing).
+
+pregate kills the gate at its `--timeout` (default 600 s) with a 5 s grace, so
+the script finishes before that deadline: it reads the deadline from
+`PREGATE_TIMEOUT_S`, else from the `gstack-pregate` command it runs under (its
+`--timeout`, else 600), reserves 120 s for teardown plus 15 s margin, and tells
+the VM to stop at whichever comes first, that point or the cap's wall (at most
+45 minutes, minus 3 for teardown). A deadline that leaves the VM under 300 s
+refuses before any VM (`PREGATE_REMOTE_TIMEOUT_TOO_SHORT`). At create time it
+prints the VM's name and the exact
+`bash scripts/ubicloud/ubi-runner.sh down <name>` line to destroy it if the
+run is killed before its teardown line. The whole script is parsed before it
+runs, so editing it during a run changes nothing. `--timeout 2700` gives a
+whole-tier run room inside the 45-minute wall:
+
+```bash
+gstack-pregate --stage tests --remote --spend-cap 2 --timeout 2700 --allow-repo-commands
+```
+
+Measured (October 2026): keyed, all 1,280 free files on standard-16 took 404 s
+from start to teardown (create 24 s, setup 72 s, tests 250 s) for $0.06.
+Keyless on 4 cores, 98 files took 103 s, and GSTA-35's 798-file selection took
+3,550 s, so keyless is practical for small selections only. A large selection
+on a small machine needs a key, or a `--timeout` longer than the run. Keyless also runs in
+your environment, not CI's: a file that needs what setup-free-suite.sh installs
+(Playwright's Chromium, Xvfb) fails locally until you install it.
+
+Every refusal line starts with a reason code:
+
+| code | exit | meaning |
+|---|---|---|
+| `PREGATE_REMOTE_USAGE` | 2 | an input is missing or malformed; run it through `gstack-pregate --stage tests --remote` |
+| `PREGATE_REMOTE_TREE_MISMATCH` | 3 | the working tree is not `PREGATE_TREE`; nothing uploaded, nothing spent |
+| `PREGATE_REMOTE_TREE_MOVED` | 3 | the tree changed during the run (the moved paths are listed); no result reported |
+| `PREGATE_REMOTE_VM_TREE` | 3 | the VM's unpacked tree or planned file set differs from what was checked locally |
+| `PREGATE_REMOTE_NO_RESULT` | 1 | test-free-shards printed no result (a rejected file list) |
+| `PREGATE_REMOTE_PAID_ONLY` | 0 | every selected file is a paid test file; `tests=0` cannot clear |
+| `PREGATE_REMOTE_CAP_TOO_LOW` | 5 | the cap cannot buy a 20-minute run at the size's price; nothing created |
+| `PREGATE_REMOTE_NO_PRICE` | 5 | `UBI_SIZE` has no list price in the script |
+| `PREGATE_REMOTE_TIMEOUT_TOO_SHORT` | 5 | pregate's deadline leaves the VM under 300 s after the 135 s teardown reserve; nothing created |
+| `PREGATE_REMOTE_INFRA` | 4 | create, setup, SSH or the stop deadline failed; the VM, its teardown line and `spent=` follow |
+| `PREGATE_REMOTE_INTERRUPTED` | 130 | TERM or INT; ubi-runner tears the VM down on its own |
+
 <a id="guards"></a>
 ## Guards and the lane-done rule
 
diff --git a/lib/restamp.ts b/lib/restamp.ts
index 8d31957a2..060a53cf9 100644
--- a/lib/restamp.ts
+++ b/lib/restamp.ts
@@ -183,7 +183,11 @@ function planVersions(o: RestampOptions, loaded: LoadedPolicy, policyLabel: stri
     try { q = JSON.parse(r.stdout ?? ''); } catch {}
     const usable = r.status === 0 && q && typeof q.version === 'string' && parseVersion(q.version) && (q.offline === false || q.fallback === 'git');
     newVersion = usable ? q.version : bumped(atBase.version, level);
-    claims = usable ? `read (claim-at-open; queue ${JSON.stringify(q.claimed ?? q.queue ?? [])})` : 'unverified (claim-at-open; gstack-next-version unusable, local arithmetic)';
+    const queue = JSON.stringify(q?.claimed ?? q?.queue ?? []);
+    const unknown = (Array.isArray(q?.unknown_claims) ? q.unknown_claims : []).map((n: unknown) => `#${n}`).join(', ') || 'some open PRs';
+    claims = !usable ? 'unverified (claim-at-open; gstack-next-version unusable, local arithmetic)'
+      : q.complete === false ? `incomplete (claim-at-open; the VERSION claims of PR ${unknown} are unknown, so ${q.version} is provisional and may collide; rerun, then ask the coordinator before stamping; queue ${queue})`
+      : `read (claim-at-open; queue ${queue})`;
   }
   // The branch's own tentative stamp: its VERSION when it moved past base; else nothing (mentions come from the lines it added).
   const branchStamp = oldVersion !== atBase.version ? oldVersion : null;
diff --git a/package.json b/package.json
index d0f2a1ac6..216efe8c3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.91.131",
+  "version": "1.91.132",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",
diff --git a/scripts/test-free-shards.ts b/scripts/test-free-shards.ts
index 7e73c048a..17766544d 100755
--- a/scripts/test-free-shards.ts
+++ b/scripts/test-free-shards.ts
@@ -73,6 +73,7 @@
  *   bun run scripts/test-free-shards.ts --wall-timeout 600         # override the kill deadline
  *   bun run scripts/test-free-shards.ts --verbose                  # forward the full child stream
  *   bun run scripts/test-free-shards.ts --quick                    # explicit fast subset, not acceptance
+ *   bun run scripts/test-free-shards.ts --files-from list.txt      # exactly these planned files (one per line)
  *   bun run scripts/test-free-shards.ts --attribute-home           # name real-home writers: each file alone, private HOME
  *   bun run scripts/test-free-shards.ts --ci-plan plan.json --shards 20
  *   bun run scripts/test-free-shards.ts --ci-run plan.json --shard 1 --result result.json
@@ -540,6 +541,7 @@ type CliOptions = {
   ciVerify: string | null;
   result: string | null;
   results: string | null;
+  filesFrom: string | null;
 };
 
 export function parseCliOptions(argv: string[]): CliOptions {
@@ -554,8 +556,8 @@ export function parseCliOptions(argv: string[]): CliOptions {
   let wallTimeoutExplicit = false;
   let quick = false;
   let attributeHome = false;
-  const paths: Record<'ciPlan' | 'ciRun' | 'ciVerify' | 'result' | 'results', string | null> = {
-    ciPlan: null, ciRun: null, ciVerify: null, result: null, results: null,
+  const paths: Record<'ciPlan' | 'ciRun' | 'ciVerify' | 'result' | 'results' | 'filesFrom', string | null> = {
+    ciPlan: null, ciRun: null, ciVerify: null, result: null, results: null, filesFrom: null,
   };
   const pathFlag = (flag: string, key: keyof typeof paths) => (next: () => string | undefined) => {
     const value = next();
@@ -576,6 +578,7 @@ export function parseCliOptions(argv: string[]): CliOptions {
     '--ci-verify': pathFlag('--ci-verify', 'ciVerify'),
     '--result': pathFlag('--result', 'result'),
     '--results': pathFlag('--results', 'results'),
+    '--files-from': pathFlag('--files-from', 'filesFrom'),
     '--shards': (next) => {
       const value = next();
       if (!value) throw new Error('Missing value for --shards');
@@ -595,6 +598,7 @@ export function parseCliOptions(argv: string[]): CliOptions {
   });
 
   const ciModes = [paths.ciPlan, paths.ciRun, paths.ciVerify].filter(Boolean).length;
+  if (paths.filesFrom && (quick || windowsOnly || listOnly || ciModes || recordDurations || attributeHome)) throw new Error('--files-from cannot be combined with --quick, --windows-only, --list, --record-durations, --attribute-home or the --ci-* modes');
   if (ciModes > 1 || (ciModes && (quick || listOnly || dryRun || recordDurations || attributeHome))) throw new Error('CI modes cannot be combined with other selection modes');
   if (paths.ciRun && (shardIndex === null || !paths.result)) throw new Error('--ci-run requires --shard and --result');
   if (paths.ciVerify && !paths.results) throw new Error('--ci-verify requires --results');
@@ -602,6 +606,47 @@ export function parseCliOptions(argv: string[]): CliOptions {
   return { dryRun, listOnly, recordDurations, windowsOnly, verbose, shardCount, shardIndex, wallTimeoutMs, wallTimeoutExplicit, quick, attributeHome, ...paths };
 }
 
+const describeLines = (lines: string[]) => `${lines.slice(0, 5).join(', ')}${lines.length > 5 ? ` (+${lines.length - 5} more)` : ''}`;
+
+/**
+ * `--files-from <path>`: one repo-relative path per line (LF or CRLF), blank
+ * lines ignored. Rejected before any planning: an unreadable file, a malformed
+ * or repeated line, an empty list, or a path outside the free planned set.
+ */
+export function readFilesFrom(file: string, planned: readonly string[]): string[] {
+  let text: string;
+  try {
+    text = fs.readFileSync(file, 'utf8');
+  } catch (error) {
+    throw new Error(`--files-from ${file}: cannot read it (${(error as NodeJS.ErrnoException).code ?? String(error)})`);
+  }
+  const files: string[] = [];
+  const malformed: string[] = [];
+  text.split(/\r?\n/).forEach((line, index) => {
+    if (line === '') return;
+    const segments = line.split('/');
+    if (line !== line.trim() || line.includes('\\') || line.startsWith('/') || /^[A-Za-z]:/.test(line)
+      || segments.some(segment => segment === '' || segment === '.' || segment === '..')) {
+      malformed.push(`line ${index + 1} ${JSON.stringify(line)}`);
+    } else if (files.includes(line)) {
+      malformed.push(`line ${index + 1} repeats ${line}`);
+    } else {
+      files.push(line);
+    }
+  });
+  if (malformed.length) throw new Error(`--files-from ${file}: ${malformed.length} malformed line(s): ${describeLines(malformed)}; fix: one repo-relative path per line (forward slashes, no surrounding spaces, no ./ or ../, no repeats)`);
+  if (!files.length) throw new Error(`--files-from ${file}: the list is empty (blank lines are ignored); nothing to run`);
+  const plannedSet = new Set(planned);
+  const unknown = files.filter(f => !plannedSet.has(f));
+  if (unknown.length) throw new Error(`--files-from ${file}: ${unknown.length} path(s) not in the free planned set: ${describeLines(unknown)}; fix: use paths from \`bun run scripts/test-free-shards.ts --list\``);
+  return files;
+}
+
+/** sha256 of the sorted list, one path per line: the digest a remote gate compares against its upload. */
+export function filesDigest(files: readonly string[]): string {
+  return createHash('sha256').update([...files].sort().map(f => `${f}\n`).join('')).digest('hex');
+}
+
 function formatShardSummary(shards: string[][]): string[] {
   return shards.map((files, index) => {
     const preview = files.slice(0, 3).join(', ');
@@ -1887,6 +1932,10 @@ async function main(): Promise<number> {
   }
 
   let files = allFiles;
+  if (options.filesFrom) {
+    files = readFilesFrom(options.filesFrom, allFiles);
+    console.log(`[test:free] files-from ${options.filesFrom}: ${files.length} files, sha256=${filesDigest(files)}`);
+  }
   if (options.quick) {
     const missing = QUICK_CORE.filter(file => !allFiles.includes(file));
     if (missing.length) throw new Error(`Quick core files missing: ${missing.join(', ')}`);
@@ -2015,7 +2064,15 @@ async function main(): Promise<number> {
     outcomes.push(exclusiveOutcome);
   }
 
-  return Math.max(homeChange ? 1 : 0, (await retryFailedFreeFiles(outcomes, totalShards, options)).exitCode);
+  const exitCode = Math.max(homeChange ? 1 : 0, (await retryFailedFreeFiles(outcomes, totalShards, options)).exitCode);
+  if (options.filesFrom) {
+    // The machine-read result for a remote gate: tests from each shard's own summary; failed counts failing files, plus one per failed shard with none attributed.
+    const tests = outcomes.reduce((sum, outcome) => sum + (outcome.summary?.testsRan ?? 0), 0);
+    const failing = outcomes.filter(outcome => outcome.status !== 'passed');
+    const failed = exitCode === 0 ? 0 : Math.max(1, new Set(failing.flatMap(outcome => outcome.failingFiles)).size + failing.filter(outcome => !outcome.failingFiles.length).length);
+    console.log(`[test:free] FILES-FROM RESULT: files=${files.length} tests=${tests} failed=${failed} exit=${exitCode}`);
+  }
+  return exitCode;
 }
 
 /** Dirty generated artifacts (SKILL.md / host outputs) after a failed exclusive shard. */
diff --git a/scripts/ubicloud/pregate-remote.sh b/scripts/ubicloud/pregate-remote.sh
new file mode 100755
index 000000000..2727b7d00
--- /dev/null
+++ b/scripts/ubicloud/pregate-remote.sh
@@ -0,0 +1,279 @@
+#!/usr/bin/env bash
+# pregate-remote.sh — gstack's declared remote_gate (.gstack/pregate.json).
+#
+# gstack-pregate runs this under 8 cores for --stage tests --remote:
+#
+#   gstack-pregate --stage tests --remote --spend-cap 2 --allow-repo-commands
+#
+# with PREGATE_FILES_FILE (the selected test files, one per line),
+# PREGATE_TREE (the working-tree fingerprint being tested) and
+# PREGATE_SPEND_CAP_USD. It prints the contract line pregate reads
+# (docs/pregate.md#remote-gate):
+#
+#   PREGATE_REMOTE: tree=<tree tested> tests=<n> failed=<n> spent=<usd>
+#
+# With UBICLOUD_API_KEY set it runs the files on one Ubicloud VM with the
+# environment of bun run test:ubicloud (scripts/ubicloud/test-free.sh:
+# setup-free-suite.sh, xvfb-run, GSTACK_EXPECT_BINARIES=1, the free retry
+# policy), through test-free-shards.ts --files-from. The wall timeout is the
+# whole minutes the cap buys at the size's list price (UBI_SIZE, default
+# standard-16), at most 45; under 20 (the shortest useful run) it refuses
+# before the VM is created. On the VM it recomputes bin/gstack-wtree
+# after unpack (the tree reported) and checks that the planned set's digest
+# equals the list's before any test runs. Setup rebuilds committed build
+# output exactly as the CI free lane does (lib/diagram-render/dist is not
+# byte-reproducible there); the script prints what setup rewrote, and the
+# tests must leave the post-setup tree unchanged. spent= is billed minutes (create to confirmed
+# teardown) times the size's price. Without a key it runs the same files
+# locally in parallel shards and reports spent=0.
+#
+# Exit codes: 0 pass (or a paid-only selection, tests=0); 1 test failures (or
+# a rejected file list); 2 missing input; 3 tree or plan mismatch (or the tree
+# moved during the run); 4 infrastructure failure (create, setup, SSH, stop
+# deadline); 5 the spend cap or pregate's deadline refuses the run. Every refusal line starts with a
+# PREGATE_REMOTE_* reason code (docs/pregate.md#remote-gate). Nothing is
+# uploaded or spent before the local tree check.
+set -euo pipefail
+# Keep heredoc bodies on temp files, not the pipe window (test/heredoc-pipe-deadlock.test.ts).
+BASH_COMPAT=50
+
+# The whole script is one braced block, so bash parses it before running and an
+# edit to this file during a run cannot change what the run executes.
+{
+here=$(cd "$(dirname "$0")" && pwd)
+root=$(cd "$here/../.." && pwd)
+rerun='gstack-pregate --stage tests --remote --spend-cap <usd> --allow-repo-commands'
+
+say() { printf 'pregate-remote: %s\n' "$@"; }
+stop() { local code=$1 reason=$2; shift 2; say "$reason: $1"; shift; [ $# -eq 0 ] || say "$@"; say "see docs/pregate.md#remote-gate"; exit "$code"; }
+
+[ -n "${PREGATE_FILES_FILE:-}" ] || stop 2 PREGATE_REMOTE_USAGE "PREGATE_FILES_FILE is not set; run: $rerun"
+[ -n "${PREGATE_TREE:-}" ] || stop 2 PREGATE_REMOTE_USAGE "PREGATE_TREE is not set; run: $rerun"
+[ -f "$PREGATE_FILES_FILE" ] || stop 2 PREGATE_REMOTE_USAGE "PREGATE_FILES_FILE=$PREGATE_FILES_FILE does not exist; run: $rerun"
+
+started=$(date +%s)
+wtree() { (cd "$root" && bin/gstack-wtree); }
+tree=$(wtree) || stop 3 PREGATE_REMOTE_TREE_MISMATCH "bin/gstack-wtree could not fingerprint $root" "nothing uploaded, nothing spent" "rerun: $rerun"
+if [ "$tree" != "$PREGATE_TREE" ]; then
+  stop 3 PREGATE_REMOTE_TREE_MISMATCH "the working tree is ${tree:0:12}, not the planned tree ${PREGATE_TREE:0:12}" "nothing uploaded, nothing spent" "rerun: $rerun"
+fi
+
+logs="$root/.context/pregate-remote/$(date -u +%Y%m%dT%H%M%SZ)-$$"
+mkdir -p "$logs"
+log="$logs/run.log"
+
+# pregate's selection can name paid test files (skill-e2e and other paid
+# evals); the paid PR gate covers those, and test-free-shards --files-from
+# rejects them, so only the free files go on.
+files="$logs/free-files.txt"
+paid=$(cd "$root" && bun -e 'import { isPaidTestFile } from "./test/helpers/paid-test-set.ts"; import * as fs from "node:fs";
+const lines = fs.readFileSync(process.argv[1], "utf8").split(/\r?\n/).filter(Boolean);
+fs.writeFileSync(process.argv[2], lines.filter(f => !isPaidTestFile(f)).map(f => f + "\n").join(""));
+console.log(lines.filter(f => isPaidTestFile(f)).join("\n"));' "$PREGATE_FILES_FILE" "$files") || stop 2 PREGATE_REMOTE_USAGE "could not split $PREGATE_FILES_FILE into free and paid test files"
+if [ -n "$paid" ]; then
+  say "$(grep -c . <<<"$paid") paid test file(s) are covered by the paid PR gate, not the free tier: $(head -5 <<<"$paid" | paste -sd, - | sed 's/,/, /g')$( [ "$(grep -c . <<<"$paid")" -le 5 ] || echo " ...")"
+fi
+count=$(grep -c . "$files" || true)
+if [ "$count" -eq 0 ]; then
+  say "PREGATE_REMOTE_PAID_ONLY: every selected file is a paid test file; no free test ran, so this receipt cannot clear the obligation (tests=0)" "see docs/pregate.md#remote-gate"
+  echo "PREGATE_REMOTE: tree=$tree tests=0 failed=0 spent=0"
+  exit 0
+fi
+
+result_line() { grep '^\[test:free\] FILES-FROM RESULT: ' "$1" | tail -1 || true; }
+field() { sed -n "s/.* $1=\([0-9][0-9]*\).*/\1/p" <<<"$2"; }
+
+if [ -z "${UBICLOUD_API_KEY:-${UBICLOUD_API_TOKEN:-}}" ]; then
+  say "no UBICLOUD_API_KEY: running $count files locally in parallel shards"
+  set +e
+  (cd "$root" && bun run scripts/test-free-shards.ts --files-from "$files") 2>&1 | tee "$log"
+  rc=${PIPESTATUS[0]}
+  set -e
+  after=$(wtree) || after=unavailable
+  if [ "$after" != "$tree" ]; then
+    (cd "$root" && git diff --name-status "$tree" "$after" 2>&1 | head -20 | sed 's/^/  moved: /') || true
+    stop 3 PREGATE_REMOTE_TREE_MOVED "the working tree moved during the run (${tree:0:12} before, ${after:0:12} after); no result reported" "log: $log" "rerun on a tree nothing else edits: $rerun"
+  fi
+  result=$(result_line "$log")
+  [ -n "$result" ] || stop "$(( rc == 0 ? 1 : rc ))" PREGATE_REMOTE_NO_RESULT "test-free-shards exited $rc without a FILES-FROM RESULT line" "log: $log"
+  say "log: $log"
+  echo "backend=local ($(getconf _NPROCESSORS_ONLN 2>/dev/null || sysctl -n hw.ncpu) cores; not the CI environment)"
+  echo "PREGATE_REMOTE: tree=$tree tests=$(field tests "$result") failed=$(field failed "$result") spent=0"
+  exit "$rc"
+fi
+
+size=${UBI_SIZE:-standard-16}
+case $size in
+  standard-2) ppm=0.00104 ;; standard-4) ppm=0.00208 ;; standard-8) ppm=0.00416 ;;
+  standard-16) ppm=0.00831 ;; standard-30) ppm=0.01559 ;; standard-60) ppm=0.03117 ;;
+  *) stop 5 PREGATE_REMOTE_NO_PRICE "no price for UBI_SIZE=$size (priced: standard-2, -4, -8, -16, -30, -60; Ubicloud list price per minute)" "nothing created, nothing spent" ;;
+esac
+cap=${PREGATE_SPEND_CAP_USD:-}
+[[ "$cap" =~ ^[0-9]+(\.[0-9]+)?$ ]] || stop 2 PREGATE_REMOTE_USAGE "PREGATE_SPEND_CAP_USD is not a dollar amount ('$cap'); run: $rerun"
+max_min=45 min_min=20
+wall_min=$(awk -v c="$cap" -v p="$ppm" -v m="$max_min" 'BEGIN { w = int(c / p); print (w < m ? w : m) }')
+usd() { awk -v m="$1" -v p="$ppm" 'BEGIN { s = m * p; c = int(s * 100); if (c < s * 100) c++; printf "%.2f", c / 100 }'; }
+if [ "$wall_min" -lt "$min_min" ]; then
+  stop 5 PREGATE_REMOTE_CAP_TOO_LOW "worst case \$$(usd "$min_min") ($min_min min x \$$ppm/min on $size) exceeds the spend cap \$$cap" "nothing created, nothing spent" "rerun with --spend-cap $(usd "$min_min") or more"
+fi
+# The enclosing gstack-pregate kills this gate at its --timeout (default 600 s)
+# with a 5 s grace, so the VM must be told to stop early enough for teardown to
+# be confirmed first: 120 s reserved for teardown plus 15 s margin. The deadline
+# comes from PREGATE_TIMEOUT_S, else from the gstack-pregate process this gate
+# runs under (its --timeout, else 600); run by hand there is none.
+outer_s=${PREGATE_TIMEOUT_S:-} outer_from=PREGATE_TIMEOUT_S
+if [ -z "$outer_s" ]; then
+  outer_from="" pid=$PPID
+  for _ in 1 2 3 4 5 6 7 8; do
+    { [ -n "$pid" ] && [ "$pid" -gt 1 ]; } || break
+    cmdline=$(ps -o args= -p "$pid" 2>/dev/null) || break
+    read -r arg0 arg1 _ <<<"$cmdline" || true
+    case "${arg0##*/} ${arg1##*/}" in
+      "gstack-pregate "*|*" gstack-pregate")
+        outer_s=$(sed -n 's/.*--timeout[ =]\([0-9][0-9]*\).*/\1/p' <<<"$cmdline")
+        outer_s=${outer_s:-600} outer_from="gstack-pregate --timeout"
+        break ;;
+    esac
+    pid=$(ps -o ppid= -p "$pid" 2>/dev/null | tr -d ' ')
+  done
+fi
+stop_after=$(( (wall_min - 3) * 60 )) stop_why="the cap's $wall_min min wall minus 3 min for teardown"
+if [ -n "$outer_s" ]; then
+  outer_stop=$(( outer_s - ($(date +%s) - started) - 135 ))
+  if [ "$outer_stop" -lt 300 ]; then
+    stop 5 PREGATE_REMOTE_TIMEOUT_TOO_SHORT "$outer_from ${outer_s}s leaves ${outer_stop}s for the VM after 120 s reserved for teardown and 15 s margin (at least 300 s needed)" "nothing created, nothing spent" "rerun with --timeout 2700: $rerun"
+  fi
+  if [ "$outer_stop" -lt "$stop_after" ]; then stop_after=$outer_stop stop_why="$outer_from ${outer_s}s minus 120 s teardown reserve and 15 s margin"; fi
+fi
+say "$count files on one $size VM; worst case \$$(usd "$wall_min") under the cap \$$cap; the VM is told to stop after ${stop_after}s ($stop_why)"
+
+digest=$(tr -d '\r' <"$files" | grep . | LC_ALL=C sort | sha256sum | cut -d' ' -f1)
+prelude="$logs/vm-setup.sh"
+{
+  printf '%s\n' 'set -euo pipefail' 'BASH_COMPAT=50' \
+    'command -v git >/dev/null || { sudo apt-get update -qq && sudo DEBIAN_FRONTEND=noninteractive apt-get install -y -qq git >/dev/null; }' \
+    'vm_tree=$(bin/gstack-wtree) || vm_tree=unavailable' \
+    "if [ \"\$vm_tree\" != $tree ]; then echo \"PREGATE_VM_TREE_MISMATCH vm=\$vm_tree\"; exit 3; fi" \
+    'echo "PREGATE_VM_TREE $vm_tree"' \
+    "cat > ~/.pregate-files.txt <<'PREGATE_FILES'"
+  tr -d '\r' <"$files" | grep .
+  printf '%s\n' 'PREGATE_FILES' "cat > ~/.pregate-run.sh <<'PREGATE_RUN'" \
+    'planned=$(bun run scripts/test-free-shards.ts --files-from ~/.pregate-files.txt --dry-run | sed -n "s/^\[test:free\] files-from .*: [0-9]* files, sha256=\([0-9a-f]*\)$/\1/p")' \
+    "if [ \"\$planned\" != $digest ]; then echo \"PREGATE_VM_PLAN_MISMATCH planned=\${planned:-none} expected=$digest\"; exit 3; fi" \
+    'xvfb-run -a bun run test:free --files-from ~/.pregate-files.txt' \
+    'rc=$?' \
+    'after=$(bin/gstack-wtree || echo unavailable)' \
+    'built=$(cat ~/.pregate-built-tree)' \
+    'echo "PREGATE_VM_TREE_AFTER $after"' \
+    '[ "$after" = "$built" ] || git diff --name-status "$built" "$after" 2>&1 | head -20 | sed "s/^/PREGATE_VM_MOVED /"' \
+    'exit $rc' \
+    'PREGATE_RUN' \
+    'bash scripts/ubicloud/setup-free-suite.sh' \
+    'built=$(bin/gstack-wtree || echo unavailable)' \
+    'echo "$built" > ~/.pregate-built-tree' \
+    'echo "PREGATE_VM_TREE_BUILT $built"' \
+    '[ "$built" = "$vm_tree" ] || git diff --name-status "$vm_tree" "$built" 2>&1 | head -20 | sed "s/^/PREGATE_VM_REBUILT /"'
+} >"$prelude"
+
+args=(run -s "$size" --src "$root" --setup "$prelude"
+  --env GSTACK_EXPECT_BINARIES=1 --env GSTACK_FREE_RETRY_FLAKY=1
+  --env GSTACK_FLAKE_LEDGER=/tmp/gstack-free-test-flake-ledger.jsonl
+  --pull "/tmp/gstack-free-test-*:$logs"
+  --pull "work/$(basename "$root")/.context/free-test-logs:$logs")
+[ -z "${GSTACK_FREE_JOBS:-}" ] || args+=(--env "GSTACK_FREE_JOBS=$GSTACK_FREE_JOBS")
+
+# The VM run gets its own session (python3, which ubi-runner already needs, for
+# setsid on Linux and macOS): pregate's --timeout and stall kill signal this
+# script's process group and then SIGKILL it, which must never cut ubi-runner's
+# teardown short. Output goes to files (a dead reader would SIGPIPE ubi-runner),
+# stamped for the phase timings; this script streams it. A watchdog sends
+# ubi-runner TERM at the cap-derived wall timeout, and so does a TERM or INT
+# to this script; ubi-runner then destroys the VM.
+vm_session='
+exec </dev/null > >(exec >/dev/null 2>&1; trap "" INT TERM HUP; while IFS= read -r line; do printf "%s %s\n" "$(date +%s)" "$line" >>"$2"; printf "%s\n" "$line" >>"$3"; done) 2>&1
+bash "$4" "${@:5}" -- "bash ~/.pregate-run.sh" &
+runner=$!
+echo "$runner" >"$2.pid"
+( sleep "$1"; touch "$2.timedout"; kill -TERM "$runner" ) </dev/null >/dev/null 2>&1 &
+watchdog=$!
+wait "$runner"
+rc=$?
+kill "$watchdog" 2>/dev/null
+[ ! -f "$2.timedout" ] || rc=124
+exit "$rc"
+'
+stream="$logs/stream.log"
+at() { grep -m1 -E "^[0-9]+ $1" "$log" | cut -d' ' -f1 || true; }
+( while sleep 60 </dev/null >/dev/null 2>&1; do say "still running ($(( $(date +%s) - started )) s)"; done ) &
+heartbeat=$!
+vmrun="" tailer=""
+trap 'kill "$heartbeat" $tailer 2>/dev/null || true' EXIT
+trap '[ -z "$vmrun" ] || kill -TERM "$(cat "$log.pid" 2>/dev/null)" 2>/dev/null; stop 130 PREGATE_REMOTE_INTERRUPTED "interrupted: ubi-runner is tearing the VM down on its own (log: $log)"' INT TERM
+
+billed=0 attempt=0
+while :; do
+  attempt=$(( attempt + 1 ))
+  : >"$log"
+  : >"$stream"
+  rm -f "$log.pid" "$log.timedout"
+  t0=$(date +%s)
+  vm_name="ubirun-$(bash "$here/ubi-runner.sh" owner)-$(date +%s)-$(head -c4 /dev/urandom | od -An -tx1 | tr -d ' \n')"
+  say "VM $vm_name; if this run is killed before its teardown line, destroy it with: bash scripts/ubicloud/ubi-runner.sh down $vm_name"
+  python3 -c 'import os, sys; os.setsid(); os.execvp(sys.argv[1], sys.argv[1:])' \
+    bash -c "$vm_session" pregate-remote-vm "$stop_after" "$log" "$stream" "$here/ubi-runner.sh" "${args[@]}" -n "$vm_name" &
+  vmrun=$!
+  tail -n +1 -f "$stream" &
+  tailer=$!
+  set +e
+  wait "$vmrun"
+  rc=$?
+  set -e
+  vmrun=""
+  sleep 1
+  kill "$tailer" 2>/dev/null || true
+  tailer=""
+  t_end=$(date +%s)
+  t_create=$(at 'ubi-runner: creating ')
+  if [ -n "$t_create" ] && ! grep -q 'ubi-runner: create failed' "$log"; then minutes=$(( (t_end - t_create + 59) / 60 )); billed=$(( billed + (minutes > 0 ? minutes : 1) )); fi
+  if [ "$rc" -ne 0 ] && [ "$attempt" -eq 1 ] && grep -q 'vCPU quota exhausted' "$log"; then
+    say "vCPU quota refused the VM; one retry in ${PREGATE_REMOTE_QUOTA_WAIT_S:-60} s"
+    cp "$log" "$logs/attempt-1.log"
+    sleep "${PREGATE_REMOTE_QUOTA_WAIT_S:-60}"
+    continue
+  fi
+  break
+done
+spent=$(usd "$billed")
+
+t_ready=$(at 'ubi-runner: ready: ')
+t_setup=$(at 'ubi-runner: running setup')
+t_run=$(at 'ubi-runner: running on ')
+t_exit=$(at 'ubi-runner: command exited')
+span() { if [ -n "$1" ] && [ -n "$2" ]; then echo "$(( $2 - $1 ))s"; else echo "-"; fi; }
+say "phases: create $(span "$t0" "$t_ready"), setup $(span "$t_setup" "$t_run"), run $(span "$t_run" "$t_exit"), teardown $(span "$t_exit" "$t_end"); total $(( t_end - started ))s (target 600s)"
+say "log: $log"
+
+vm_tree=$(sed -n 's/^[0-9]* PREGATE_VM_TREE \([0-9a-f]*\)$/\1/p' "$log" | tail -1)
+mismatch=$(grep -m1 -oE 'PREGATE_VM_(TREE|PLAN)_MISMATCH .*' "$log" || true)
+if [ -n "$mismatch" ]; then
+  stop 3 PREGATE_REMOTE_VM_TREE "the VM refused before running tests: $mismatch (expected tree ${tree:0:12})" "no tests ran; spent=$spent ($billed billed min on $size)" "rerun: $rerun"
+fi
+result=$(result_line <(cut -d' ' -f2- "$log"))
+if [ -n "$result" ] && [ "$rc" -ne 124 ]; then
+  after=$(sed -n 's/^[0-9]* PREGATE_VM_TREE_AFTER \(.*\)$/\1/p' "$log" | tail -1)
+  built=$(sed -n 's/^[0-9]* PREGATE_VM_TREE_BUILT \(.*\)$/\1/p' "$log" | tail -1)
+  sed -n 's/^[0-9]* PREGATE_VM_REBUILT /  setup rebuilt (committed build output, as the CI free lane rebuilds it): /p' "$log"
+  if [ "$after" != "$built" ]; then
+    sed -n 's/^[0-9]* PREGATE_VM_MOVED /  moved: /p' "$log"
+    stop 3 PREGATE_REMOTE_TREE_MOVED "the VM's tree moved during the run (${built:0:12} after setup, ${after:0:12} after tests); no result reported" "spent=$spent ($billed billed min on $size)" "rerun: $rerun"
+  fi
+  echo "PREGATE_REMOTE: tree=$vm_tree tests=$(field tests "$result") failed=$(field failed "$result") spent=$spent"
+  exit $(( rc == 0 ? 0 : 1 ))
+fi
+vm=$(sed -n 's/^[0-9]* ubi-runner: creating \([^ ]*\) .*/\1/p' "$log" | tail -1)
+down=$(grep -E 'ubi-runner: (destroyed|gone:|WARNING|FAILED to destroy)' "$log" | tail -1 | cut -d' ' -f2- || true)
+cause=$(grep -E 'ubi-runner: ' "$log" | grep -vE 'ubi-runner: (destroyed|gone:|destroy requested|waiting for an in-flight)' | tail -1 | cut -d' ' -f2- || true)
+[ "$rc" -ne 124 ] || cause="the VM was told to stop after ${stop_after}s ($stop_why) and torn down"
+stop 4 PREGATE_REMOTE_INFRA "infrastructure failure (ubi-runner exit $rc): ${cause:-no ubi-runner message}" \
+  "VM: ${vm:-none created}${down:+; $down}" "log: $log" "spent=$spent ($billed billed min on $size)"
+}
diff --git a/test/fixtures/shard-cli-parity/results.json b/test/fixtures/shard-cli-parity/results.json
index b24a4fa80..f8986404f 100644
--- a/test/fixtures/shard-cli-parity/results.json
+++ b/test/fixtures/shard-cli-parity/results.json
@@ -1,11 +1,12 @@
 {
-  "recordedFrom": "96764e80 (pre-engine base runners); paid lane re-recorded at v1.91.12.0 for the marathon tier and the --slice-budget, --max-parallel, --case and --trials flags (PR 2999); free lane re-recorded for the --attribute-home flag (PR 3014)",
+  "recordedFrom": "96764e80 (pre-engine base runners); paid lane re-recorded at v1.91.12.0 for the marathon tier and the --slice-budget, --max-parallel, --case and --trials flags (PR 2999); free lane re-recorded for the --attribute-home flag (PR 3014) and the --files-from flag (fix wave 3, W2-A3)",
   "free": [
     {
       "argv": [],
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
@@ -33,6 +34,7 @@
       "result": {
         "ok": {
           "dryRun": true,
+          "filesFrom": null,
           "listOnly": true,
           "recordDurations": false,
           "windowsOnly": false,
@@ -59,6 +61,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": true,
           "recordDurations": false,
           "windowsOnly": true,
@@ -84,6 +87,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": true,
           "windowsOnly": false,
@@ -109,6 +113,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
@@ -137,6 +142,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
@@ -163,6 +169,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
@@ -191,6 +198,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
@@ -221,6 +229,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
@@ -249,6 +258,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
@@ -399,6 +409,7 @@
       "result": {
         "ok": {
           "dryRun": false,
+          "filesFrom": null,
           "listOnly": false,
           "recordDurations": false,
           "windowsOnly": false,
diff --git a/test/gstack-next-version.test.ts b/test/gstack-next-version.test.ts
index 83993db72..346456a70 100644
--- a/test/gstack-next-version.test.ts
+++ b/test/gstack-next-version.test.ts
@@ -19,6 +19,8 @@ import {
   markActiveSiblings,
   resolveVersionPath,
   fetchGitClaimed,
+  fetchGithubClaimed,
+  VERSION_FETCH_TIMEOUT_MS,
 } from "../bin/gstack-next-version";
 
 describe("parseVersion", () => {
@@ -1012,6 +1014,8 @@ describe("integration (smoke)", () => {
       expect(parsed.fallback).toBeNull();
       expect(parsed.warnings).toEqual([]);
       expect(parsed.claimed).toEqual([CLAIM]); // the canned PR's owner matches the canned repo owner
+      expect(parsed.complete).toBe(true);
+      expect(parsed.unknown_claims).toEqual([]);
       expect(parsed.version).toBe("1.6.5.0"); // the canned claim on 1.6.4.0 is skipped
     } finally {
       rmSync(stubDir, { recursive: true, force: true });
@@ -1217,3 +1221,160 @@ describe("no version source: one signal, never an invented slot (G1)", () => {
     expect(r.stderr).not.toContain("assuming");
   }, 30_000);
 });
+
+// W2-A3 (fix wave 3): VERSION fetches run through async workers bounded at
+// GH_API_CONCURRENCY, each with a 15 s timeout; claims and warnings are sorted
+// by PR number, and a timed-out or failed fetch is an unknown claim. A named
+// fake `gh` first on PATH answers every call with a per-PR delay; the live
+// GitHub API is never called.
+describe("concurrent VERSION fetches (W2-A3)", () => {
+  const OWNER = "fixture-owner";
+  type FakePR = { pr: number; version?: string; delay: number; reply?: "404" | "502" | "malformed" };
+  const prBranch = (pr: number) => `fixture/pr-${pr}`;
+  const prUrl = (pr: number) => `https://github.com/${OWNER}/repo/pull/${pr}`;
+  const claim = (pr: number, version: string) => ({ pr, branch: prBranch(pr), version, url: prUrl(pr) });
+
+  function delayedGh(dir: string, prs: FakePR[]): string {
+    const flight = join(dir, "flight.log");
+    const list = JSON.stringify(prs.map((p) => ({ number: p.pr, headRefName: prBranch(p.pr), headRepositoryOwner: { login: OWNER }, url: prUrl(p.pr), isDraft: false })));
+    const reply = (p: FakePR) => {
+      if (p.reply === "404") return `echo 'gh: Not Found (HTTP 404)' >&2; exit 1`;
+      if (p.reply === "502") return `echo 'gh: Server Error (HTTP 502)' >&2; exit 1`;
+      const body = p.reply === "malformed" ? "not-a-version\n" : `${p.version}\n`;
+      return `echo '${Buffer.from(body).toString("base64")}'; exit 0`;
+    };
+    writeFileSync(join(dir, "gh"), [
+      "#!/bin/sh",
+      'case "$*" in',
+      `  "pr list --state open --base main --limit 200 --json number,headRefName,headRepositoryOwner,url,isDraft") printf '%s\\n' '${list}'; exit 0 ;;`,
+      `  "repo view --json owner -q .owner.login") echo '${OWNER}'; exit 0 ;;`,
+      ...prs.map((p) => `  "api repos/{owner}/{repo}/contents/VERSION?ref=${encodeURIComponent(prBranch(p.pr))} -q .content") echo + >> '${flight}'; sleep ${p.delay}; echo - >> '${flight}'; ${reply(p)} ;;`),
+      "esac",
+      'echo "FAKE_GH_UNHANDLED $*" >&2',
+      "exit 2",
+      "",
+    ].join("\n"), { mode: 0o755 });
+    return flight;
+  }
+
+  async function fetchWith(prs: FakePR[], fetchTimeoutMs?: number) {
+    const dir = mkdtempSync(join(tmpdir(), "nextver-concurrency-"));
+    const flight = delayedGh(dir, prs);
+    const savedPath = process.env.PATH;
+    process.env.PATH = `${dir}:${savedPath ?? ""}`;
+    const warnings: string[] = [];
+    const started = performance.now();
+    try {
+      const result: { claimed: { pr: number }[]; offline: boolean; unknownClaims: number[] } = await fetchGithubClaimed("main", "VERSION", null, warnings, fetchTimeoutMs);
+      let running = 0;
+      let maxInFlight = 0;
+      for (const event of readFileSync(flight, "utf8").trim().split("\n")) {
+        running += event === "+" ? 1 : -1;
+        maxInFlight = Math.max(maxInFlight, running);
+      }
+      return { ...result, warnings, ms: performance.now() - started, maxInFlight };
+    } finally {
+      process.env.PATH = savedPath;
+      rmSync(dir, { recursive: true, force: true });
+    }
+  }
+
+  test("8 PRs at 0.5 s each finish in under 2 s with every claim, sorted by PR number", async () => {
+    const r = await fetchWith([48, 41, 47, 42, 46, 43, 45, 44].map((pr) => ({ pr, version: `1.6.${pr}.0`, delay: 0.5 })));
+    expect(r.ms).toBeLessThan(2000); // gstack-timing-ok: the plan's contract (8 x 0.5 s serial took 4,160 ms)
+    expect(r.offline).toBe(false);
+    expect(r.claimed).toEqual([41, 42, 43, 44, 45, 46, 47, 48].map((pr) => claim(pr, `1.6.${pr}.0`)));
+    expect(r.warnings).toEqual([]);
+    expect(r.unknownClaims).toEqual([]);
+    expect(r.maxInFlight).toBeGreaterThan(1);
+  }, 30_000);
+
+  test("randomized delays give the same claims, warnings and unknown claims every run, within the concurrency bound", async () => {
+    let seed = 7;
+    const random = () => { seed = (seed * 1103515245 + 12345) % 2 ** 31; return seed / 2 ** 31; };
+    const base: Omit<FakePR, "delay">[] = Array.from({ length: 14 }, (_, i) => ({ pr: 60 + i, version: `2.0.${i}.0` }));
+    base[2]!.reply = "404";
+    base[5]!.reply = "malformed";
+    base[9]!.reply = "502";
+    const runs = [];
+    for (let run = 0; run < 3; run++) runs.push(await fetchWith(base.map((p) => ({ ...p, delay: Number((random() * 0.3).toFixed(2)) }))));
+    for (const r of runs) {
+      expect(r.claimed).toEqual(runs[0]!.claimed);
+      expect(r.warnings).toEqual(runs[0]!.warnings);
+      expect(r.unknownClaims).toEqual([69]);
+      expect(r.maxInFlight).toBeLessThanOrEqual(10);
+    }
+    expect(runs[0]!.claimed.map((c) => c.pr)).toEqual([60, 61, 63, 64, 66, 67, 68, 70, 71, 72, 73]);
+    expect(runs[0]!.warnings).toEqual([
+      "PR #62: could not fetch VERSION (fork, private, or wrong path — try --version-path or .gstack/version-path)",
+      "PR #65: VERSION is malformed (not-a-version)",
+      "PR #69: VERSION fetch failed (gh: Server Error (HTTP 502)); claim unknown, the slot may collide; rerun, then ask the coordinator",
+    ]);
+  }, 60_000);
+
+  test("a timed-out fetch is killed, keeps its cause and counts as an unknown claim", async () => {
+    expect(VERSION_FETCH_TIMEOUT_MS).toBe(15000);
+    const r = await fetchWith([{ pr: 51, version: "1.7.1.0", delay: 0.1 }, { pr: 52, version: "1.7.2.0", delay: 10 }], 500);
+    expect(r.ms).toBeLessThan(5000); // gstack-timing-ok: the killed fetch must not wait out its 10 s sleeper
+    expect(r.claimed).toEqual([claim(51, "1.7.1.0")]);
+    expect(r.unknownClaims).toEqual([52]);
+    expect(r.warnings).toEqual(["PR #52: VERSION fetch timed out after 0.5 s; claim unknown, the slot may collide; rerun, then ask the coordinator"]);
+  }, 30_000);
+
+  function cliRepo(dir: string): string {
+    // A local origin whose path contains github.com pins host:"github" by the URL sniff, so no auth probe or network call runs.
+    const bare = join(dir, "github.com", "origin.git");
+    const work = join(dir, "work");
+    const git = (cwd: string, ...args: string[]) => Bun.spawnSync(["git", "-c", "user.email=t@t", "-c", "user.name=t", ...args], { cwd, timeout: 30_000 });
+    mkdirSync(bare, { recursive: true });
+    mkdirSync(work);
+    git(bare, "init", "-q", "--bare", "-b", "main");
+    git(work, "init", "-q", "-b", "main");
+    writeFileSync(join(work, "VERSION"), "1.6.3.0\n");
+    git(work, "add", "-A");
+    git(work, "commit", "-qm", "v1.6.3.0 chore: base");
+    git(work, "remote", "add", "origin", bare);
+    git(work, "push", "-q", "origin", "main");
+    return work;
+  }
+
+  test("a timed-out worker beside successful ones makes the pick provisional: complete false, on stderr and in warnings", () => {
+    const dir = mkdtempSync(join(tmpdir(), "nextver-provisional-cli-"));
+    try {
+      delayedGh(dir, [{ pr: 91, version: "1.6.4.0", delay: 0 }, { pr: 92, version: "1.6.9.0", delay: 25 }, { pr: 93, version: "1.6.5.0", delay: 0.2 }]);
+      const proc = Bun.spawnSync(["bun", "run", join(import.meta.dir, "..", "bin", "gstack-next-version"), "--base", "main", "--bump", "patch",
+        "--current-version", "1.6.3.0", "--workspace-root", "null", "--exclude-pr", "999"],
+      { cwd: cliRepo(dir), timeout: 40_000, env: { ...process.env, PATH: `${dir}:${process.env.PATH ?? ""}` } });
+      const out = JSON.parse(proc.stdout.toString());
+      expect(out.claimed.map((c: { pr: number }) => c.pr)).toEqual([91, 93]);
+      expect(out.unknown_claims).toEqual([92]);
+      expect(out.complete).toBe(false);
+      expect(out.version).toBe("1.6.6.0");
+      const provisional = "provisional pick: the VERSION claims of PR #92 are unknown, so 1.6.6.0 is not a verified slot and may collide; rerun, then ask the coordinator before stamping";
+      expect(out.warnings).toEqual(["PR #92: VERSION fetch timed out after 15 s; claim unknown, the slot may collide; rerun, then ask the coordinator", provisional]);
+      expect(proc.stderr.toString()).toContain(`gstack-next-version: ${provisional}`);
+    } finally {
+      rmSync(dir, { recursive: true, force: true });
+    }
+  }, 45_000);
+
+  test("the CLI JSON carries unknown_claims", () => {
+    const dir = mkdtempSync(join(tmpdir(), "nextver-unknown-cli-"));
+    try {
+      delayedGh(dir, [{ pr: 81, version: "1.6.4.0", delay: 0 }, { pr: 82, delay: 0, reply: "502" }]);
+      const work = cliRepo(dir);
+      const proc = Bun.spawnSync(["bun", "run", join(import.meta.dir, "..", "bin", "gstack-next-version"), "--base", "main", "--bump", "patch",
+        "--current-version", "1.6.3.0", "--workspace-root", "null", "--exclude-pr", "999"],
+      { cwd: work, timeout: 30_000, env: { ...process.env, PATH: `${dir}:${process.env.PATH ?? ""}` } });
+      const out = JSON.parse(proc.stdout.toString());
+      expect(out.host, proc.stderr.toString()).toBe("github");
+      expect(out.unknown_claims).toEqual([82]);
+      expect(out.complete).toBe(false);
+      expect(out.claimed.map((c: { pr: number }) => c.pr)).toEqual([81]);
+      expect(out.version).toBe("1.6.5.0");
+      expect(out.warnings).toContain("PR #82: VERSION fetch failed (gh: Server Error (HTTP 502)); claim unknown, the slot may collide; rerun, then ask the coordinator");
+    } finally {
+      rmSync(dir, { recursive: true, force: true });
+    }
+  }, 30_000);
+});
diff --git a/test/gstack-restamp-queue.test.ts b/test/gstack-restamp-queue.test.ts
index 4120dc44a..dcac80407 100644
--- a/test/gstack-restamp-queue.test.ts
+++ b/test/gstack-restamp-queue.test.ts
@@ -162,6 +162,30 @@ describe('three PRs, reordered twice, zero manual edits', () => {
     const forced = restamp(repo, ['--next', '--dry-run', '--queue-mode', 'stamp-at-merge']);
     expect(forced.out).toContain('claims: ignored (stamp-at-merge)');
   });
+
+  test('claim-at-open with an unknown claim says incomplete, names the PR and never says read', () => {
+    const repo = fixture({ policy: { ...BASE_POLICY, queue_mode: 'claim-at-open' }, prefix: 'gstack-restamp-github.com-' });
+    makePr(repo, 'pr-a');
+    const shim = path.join(repo.root, 'gh-unknown-claim');
+    fs.mkdirSync(shim);
+    const list = JSON.stringify([41, 42].map(n => ({ number: n, headRefName: `pr-${n}`, headRepositoryOwner: { login: 'o' }, url: `https://github.com/o/r/pull/${n}`, isDraft: false })));
+    fs.writeFileSync(path.join(shim, 'gh'), [
+      '#!/bin/sh',
+      'case "$*" in',
+      `  "pr list --state open --base main --limit 200 --json number,headRefName,headRepositoryOwner,url,isDraft") printf '%s\\n' '${list}'; exit 0 ;;`,
+      "  \"repo view --json owner -q .owner.login\") echo o; exit 0 ;;",
+      `  "api repos/{owner}/{repo}/contents/VERSION?ref=pr-41 -q .content") echo '${Buffer.from('1.2.5.0\n').toString('base64')}'; exit 0 ;;`,
+      "  \"api repos/{owner}/{repo}/contents/VERSION?ref=pr-42 -q .content\") echo 'gh: Server Error (HTTP 502)' >&2; exit 1 ;;",
+      'esac',
+      'exit 2',
+      '',
+    ].join('\n'), { mode: 0o755 });
+    const r = restamp(repo, ['--next', '--dry-run'], { PATH: `${shim}:${process.env.PATH ?? ''}` });
+    expect(r.status, r.err).toBe(EXIT.ok);
+    expect(r.out).toContain('STAMP_VERSION: 1.2.6.0');
+    expect(r.out).toContain('claims: incomplete (claim-at-open; the VERSION claims of PR #42 are unknown, so 1.2.6.0 is provisional and may collide; rerun, then ask the coordinator before stamping; queue [');
+    expect(r.out).not.toMatch(/^claims: read/m);
+  });
 });
 
 describe('journal and injected failures', () => {
diff --git a/test/test-free-shards-files-from.test.ts b/test/test-free-shards-files-from.test.ts
new file mode 100644
index 000000000..72bd67ca5
--- /dev/null
+++ b/test/test-free-shards-files-from.test.ts
@@ -0,0 +1,85 @@
+/**
+ * W2-A3 (fix wave 3): test-free-shards.ts --files-from <path> plans exactly
+ * the listed files from the free planned set and rejects, before planning, an
+ * unknown path, an empty list or a malformed line. The remote gate
+ * (scripts/ubicloud/pregate-remote.sh) compares the printed digest with its
+ * upload; the full run's FILES-FROM RESULT line is covered there.
+ */
+import { afterAll, describe, expect, test } from 'bun:test';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+import { collectFreeTestFiles, filesDigest, parseCliOptions, readFilesFrom } from '../scripts/test-free-shards';
+
+const ROOT = path.resolve(import.meta.dir, '..');
+const DIR = fs.mkdtempSync(path.join(os.tmpdir(), 'free-files-from-'));
+afterAll(() => fs.rmSync(DIR, { recursive: true, force: true }));
+let n = 0;
+const list = (text: string) => {
+  const file = path.join(DIR, `list-${++n}.txt`);
+  fs.writeFileSync(file, text);
+  return file;
+};
+const PLANNED = ['browse/test/a.test.ts', 'test/b.test.ts', 'test/c.test.ts', 'test/d.test.ts', 'test/e.test.ts', 'test/f.test.ts', 'test/g.test.ts'];
+
+describe('--files-from parsing', () => {
+  test('one path per line; blank lines and CRLF endings are accepted; order is kept', () => {
+    expect(readFilesFrom(list('test/c.test.ts\r\n\r\nbrowse/test/a.test.ts\n\n'), PLANNED)).toEqual(['test/c.test.ts', 'browse/test/a.test.ts']);
+  });
+
+  test('paths outside the free planned set are rejected with the first five, a count and the --list fix', () => {
+    const file = list(['test/b.test.ts', ...['x1', 'x2', 'x3', 'x4', 'x5', 'x6', 'x7'].map(name => `test/${name}.test.ts`)].join('\n'));
+    expect(() => readFilesFrom(file, PLANNED)).toThrow(
+      `--files-from ${file}: 7 path(s) not in the free planned set: test/x1.test.ts, test/x2.test.ts, test/x3.test.ts, test/x4.test.ts, test/x5.test.ts (+2 more); fix: use paths from \`bun run scripts/test-free-shards.ts --list\``);
+  });
+
+  test('an empty list, an unreadable file and every malformed line shape are rejected', () => {
+    const empty = list('\n\r\n\n');
+    expect(() => readFilesFrom(empty, PLANNED)).toThrow(`--files-from ${empty}: the list is empty (blank lines are ignored); nothing to run`);
+    expect(() => readFilesFrom(path.join(DIR, 'absent.txt'), PLANNED)).toThrow('cannot read it (ENOENT)');
+    const bad = [' test/b.test.ts', 'test/c.test.ts ', './test/d.test.ts', 'test/../test/e.test.ts', '/abs/test/f.test.ts', 'test\\g.test.ts', 'C:/x.test.ts', 'test//b.test.ts'];
+    for (const line of bad) {
+      expect(() => readFilesFrom(list(`test/b.test.ts\n${line}\n`), PLANNED), line).toThrow(`1 malformed line(s): line 2 ${JSON.stringify(line)}; fix: one repo-relative path per line`);
+    }
+    expect(() => readFilesFrom(list('test/b.test.ts\ntest/c.test.ts\ntest/b.test.ts\n'), PLANNED)).toThrow('line 3 repeats test/b.test.ts');
+  });
+
+  test('the digest is the sorted list, so a reordered upload still matches', () => {
+    expect(filesDigest(['test/c.test.ts', 'browse/test/a.test.ts'])).toBe(filesDigest(['browse/test/a.test.ts', 'test/c.test.ts']));
+    expect(filesDigest(['test/c.test.ts'])).not.toBe(filesDigest(['test/c.test.ts', 'test/b.test.ts']));
+  });
+
+  test('it conflicts with --quick, --windows-only, --list, --record-durations, --attribute-home and every --ci-* mode', () => {
+    expect(parseCliOptions(['--files-from', 'x.txt', '--dry-run']).filesFrom).toBe('x.txt');
+    expect(() => parseCliOptions(['--files-from'])).toThrow('Missing path for --files-from');
+    for (const extra of [['--quick'], ['--windows-only'], ['--list'], ['--record-durations'], ['--attribute-home'], ['--ci-plan', 'p.json'], ['--ci-run', 'p.json', '--shard', '1', '--result', 'r.json'], ['--ci-verify', 'p.json', '--results', 'r']]) {
+      expect(() => parseCliOptions(['--files-from', 'x.txt', ...extra]), extra[0]).toThrow('--files-from cannot be combined with --quick, --windows-only, --list, --record-durations, --attribute-home or the --ci-* modes');
+    }
+  });
+});
+
+describe('--files-from planning through the CLI', () => {
+  const cli = (...args: string[]) => {
+    const r = Bun.spawnSync([process.execPath, path.join(ROOT, 'scripts/test-free-shards.ts'), ...args], { cwd: ROOT, timeout: 60_000 });
+    return { exit: r.exitCode, out: r.stdout.toString() + r.stderr.toString() };
+  };
+
+  test('a dry run plans exactly the listed files and prints their digest', () => {
+    const planned = collectFreeTestFiles(ROOT);
+    const chosen = [planned[3]!, planned[0]!];
+    const file = list(chosen.join('\n') + '\n');
+    const r = cli('--files-from', file, '--dry-run');
+    expect(r.exit, r.out).toBe(0);
+    expect(r.out).toContain(`[test:free] files-from ${file}: 2 files, sha256=${filesDigest(chosen)}`);
+    expect(r.out).toContain('Would run 2 files across');
+    const listed = r.out.split('\n').filter(line => line.startsWith('Shard ') && line.includes('->')).flatMap(line => line.split('-> ')[1]!.split(', '));
+    expect(listed.sort()).toEqual([...chosen].sort());
+  }, 60_000);
+
+  test('a rejected list exits 1 before planning', () => {
+    const r = cli('--files-from', list('test/not-a-real-file.test.ts\n'), '--dry-run');
+    expect(r.exit).toBe(1);
+    expect(r.out).toContain('1 path(s) not in the free planned set: test/not-a-real-file.test.ts');
+    expect(r.out).not.toContain('Would run');
+  }, 60_000);
+});
diff --git a/test/ubicloud-pregate-remote.test.ts b/test/ubicloud-pregate-remote.test.ts
new file mode 100644
index 000000000..1cb8820c0
--- /dev/null
+++ b/test/ubicloud-pregate-remote.test.ts
@@ -0,0 +1,402 @@
+/**
+ * W2-A3 (fix wave 3): scripts/ubicloud/pregate-remote.sh, gstack's declared
+ * remote_gate. Each case runs the real script in a fixture checkout whose
+ * scripts/ubicloud/ubi-runner.sh is a stub that "creates" a local VM
+ * directory, so the keyed path runs its real VM-side setup prelude, the real
+ * test-free-shards.ts --files-from and the real bin/gstack-wtree, offline and
+ * at no cost. Reports are judged through the exported parseRemoteReport /
+ * remoteReportProblem, exactly as gstack-pregate --remote judges them.
+ */
+import { afterAll, describe, expect, test } from 'bun:test';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+import { parseConfig } from '../lib/pregate/config';
+import { parseRemoteReport, remoteReportProblem } from '../lib/pregate/checks/lanes';
+
+const ROOT = path.resolve(import.meta.dir, '..');
+const SCRATCH = fs.mkdtempSync(path.join(os.tmpdir(), 'pregate-remote-gate-'));
+afterAll(() => fs.rmSync(SCRATCH, { recursive: true, force: true }));
+
+const COPIED = ['scripts/ubicloud/pregate-remote.sh', 'bin/gstack-wtree', 'bin/gstack-path-spelling.sh',
+  'scripts/test-free-shards.ts', 'scripts/test-strict-output.ts', 'scripts/lib/shard-engine.ts', 'scripts/lib/free-home-guard.ts',
+  'scripts/lib/free-ci-health.ts', 'scripts/lib/windows-curation.ts', 'lib/state-root.ts', 'test/helpers/paid-test-set.ts',
+  'test/helpers/touchfiles.ts', 'test/helpers/touchfiles-data.ts', 'test/helpers/test-selection.ts'];
+const TESTS: Record<string, string> = {
+  'test/alpha.test.ts': "import { expect, test } from 'bun:test';\ntest('alpha', () => { expect(1).toBe(1); });\n",
+  'test/beta.test.ts': "import { expect, test } from 'bun:test';\ntest('beta', () => { expect(2).toBe(2); });\n",
+  'test/fails.test.ts': "import { expect, test } from 'bun:test';\ntest('fails', () => { expect(1).toBe(2); });\n",
+  'test/empty.test.ts': "import 'bun:test';\n",
+  'test/mover.test.ts': "import { test } from 'bun:test';\nimport * as fs from 'node:fs';\nimport * as path from 'node:path';\ntest('moves the tree', () => { fs.writeFileSync(path.join(import.meta.dir, '..', 'moved.txt'), 'x'); });\n",
+};
+
+/** Stub of scripts/ubicloud/ubi-runner.sh (written into each fixture as that file). */
+const UBI_RUNNER_STUB = `#!/usr/bin/env bash
+# Stub of scripts/ubicloud/ubi-runner.sh for test/ubicloud-pregate-remote.test.ts:
+# "run" copies the checkout (tracked + untracked-unignored + .git) into a local
+# VM directory, runs setup and the command there, and prints ubi-runner's log
+# lines. STUB_FAIL picks a failure: create, quota, quota-once, ssh. STUB_HANG
+# sleeps before the command; TERM tears down as ubi-runner's trap does.
+# Every teardown is appended to $STUB_CALLS.down.
+set -uo pipefail
+[ "$1" != owner ] || { echo stub; exit 0; }
+[ "$1" = run ] || exit 2
+shift
+printf '%s\\n' "$*" >>"$STUB_CALLS"
+src=. setup="" size="" name=unnamed envs=()
+while [ $# -gt 0 ]; do
+  case $1 in
+    -s) size=$2; shift 2 ;;
+    -n) name=$2; shift 2 ;;
+    --src) src=$2; shift 2 ;;
+    --setup) setup=$2; shift 2 ;;
+    --env) envs+=("$2"); shift 2 ;;
+    --pull) shift 2 ;;
+    --) shift; break ;;
+    *) echo "stub: unknown option $1" >&2; exit 2 ;;
+  esac
+done
+cmd=$*
+log() { echo "ubi-runner: $*" >&2; }
+log "creating eu-central-h1/$name ($size)"
+calls=$(wc -l <"$STUB_CALLS")
+fail=\${STUB_FAIL:-}
+if [ "$fail" = quota ] || { [ "$fail" = quota-once ] && [ "$calls" -eq 1 ]; }; then
+  log "quota refused eu-central-h1/$name ($size): it needs 16 vCPUs and the project already uses 64 of 64"
+  log "create failed: vCPU quota exhausted; wait for running VMs to finish, or use fewer or smaller VMs (ci:ubicloud --vms N)"
+  log "gone: eu-central-h1/$name (never existed or already destroyed)"
+  exit 1
+fi
+if [ "$fail" = create ]; then
+  echo "Validation failed for following fields: size" >&2
+  log "create failed"
+  log "gone: eu-central-h1/$name (never existed or already destroyed)"
+  exit 1
+fi
+log "ready: $name (192.0.2.1)"
+trap 'log "destroyed eu-central-h1/$name"; echo "term $name" >>"$STUB_CALLS.down"; exit 130' TERM
+vm=$STUB_VM_HOME
+dest="$vm/work/$(basename "$src")"
+rm -rf "$dest" && mkdir -p "$dest"
+(cd "$src" && { git ls-files -z -co --exclude-standard; printf '.git\\0'; } | tar --null -T - -cf -) | tar -xf - -C "$dest"
+[ -z "\${STUB_VM_EDIT:-}" ] || echo "// edited on the VM" >>"$dest/$STUB_VM_EDIT"
+for e in \${envs[@]+"\${envs[@]}"}; do printf 'export %s\\n' "$e"; done >"$vm/.ubirun-env"
+log "synced $src -> $name:$dest"
+if [ -n "$setup" ]; then
+  cp "$setup" "$vm/.ubirun-setup.sh"
+  log "running setup $(basename "$setup")"
+  if ! (cd "$dest" && HOME="$vm" bash -c '. ~/.ubirun-env && bash ~/.ubirun-setup.sh'); then
+    log "setup failed"
+    log "destroyed eu-central-h1/$name"
+    exit 1
+  fi
+fi
+[ -z "\${STUB_VM_LIST_ADD:-}" ] || echo "$STUB_VM_LIST_ADD" >>"$vm/.pregate-files.txt"
+log "running on $name: $cmd"
+if [ -n "\${STUB_HANG:-}" ]; then sleep "$STUB_HANG" & wait $!; fi
+rc=0
+if [ "$fail" = ssh ]; then
+  rc=255
+else
+  (cd "$dest" && HOME="$vm" PATH="$STUB_BIN:$PATH" bash -c ". ~/.ubirun-env && $cmd") || rc=$?
+fi
+log "command exited $rc after 1s"
+log "destroyed eu-central-h1/$name"
+echo "exit $name" >>"$STUB_CALLS.down"
+exit "$rc"
+`;
+
+interface Fixture { repo: string; vm: string; calls: string; bin: string; tree: string }
+
+let counter = 0;
+function fixture(): Fixture {
+  const base = path.join(SCRATCH, String(++counter));
+  const repo = path.join(base, 'gstack');
+  const vm = path.join(base, 'vm');
+  const bin = path.join(base, 'bin');
+  for (const dir of [repo, vm, bin]) fs.mkdirSync(dir, { recursive: true });
+  const put = (rel: string, body: string, mode = 0o644) => {
+    fs.mkdirSync(path.dirname(path.join(repo, rel)), { recursive: true });
+    fs.writeFileSync(path.join(repo, rel), body, { mode });
+  };
+  for (const rel of COPIED) put(rel, fs.readFileSync(path.join(ROOT, rel), 'utf8'), fs.statSync(path.join(ROOT, rel)).mode & 0o777);
+  for (const [rel, body] of Object.entries(TESTS)) put(rel, body);
+  put('scripts/ubicloud/ubi-runner.sh', UBI_RUNNER_STUB, 0o755);
+  put('scripts/ubicloud/setup-free-suite.sh', '#!/usr/bin/env bash\necho "setup-free-suite (stub)"\n[ -z "${STUB_SETUP_FAIL:-}" ] || exit 1\n[ -z "${STUB_SETUP_REBUILD:-}" ] || echo rebuilt >>dist/bundle.txt\n', 0o755);
+  put('dist/bundle.txt', 'committed build output\n');
+  put('.gitignore', '.context/\n');
+  put('package.json', JSON.stringify({ scripts: { 'test:free': 'bun run scripts/test-free-shards.ts' } }) + '\n');
+  fs.writeFileSync(path.join(bin, 'xvfb-run'), '#!/bin/sh\n[ "$1" = -a ] && shift\nexec "$@"\n', { mode: 0o755 });
+  const git = (...args: string[]) => {
+    const r = Bun.spawnSync(['git', '-c', 'user.email=t@t', '-c', 'user.name=t', ...args], { cwd: repo, timeout: 30_000 });
+    if (r.exitCode !== 0) throw new Error(`git ${args.join(' ')}: ${r.stderr.toString()}`);
+    return r.stdout.toString().trim();
+  };
+  git('init', '-q', '-b', 'main');
+  git('add', '-A');
+  git('commit', '-qm', 'fixture');
+  const tree = Bun.spawnSync(['bin/gstack-wtree'], { cwd: repo, timeout: 30_000 }).stdout.toString().trim();
+  return { repo, vm, calls: path.join(base, 'calls.log'), bin, tree };
+}
+
+function gate(f: Fixture, files: string[] | null, env: Record<string, string | undefined> = {}) {
+  const list = path.join(path.dirname(f.repo), 'files.txt');
+  if (files) fs.writeFileSync(list, files.join('\n') + '\n');
+  const base: Record<string, string | undefined> = { ...process.env, UBICLOUD_API_KEY: undefined, UBICLOUD_API_TOKEN: undefined, UBI_SIZE: undefined,
+    GSTACK_FREE_JOBS: '2', GSTACK_FLAKE_LEDGER: path.join(path.dirname(f.repo), 'flakes.jsonl'), STUB_CALLS: f.calls, STUB_VM_HOME: f.vm, STUB_BIN: f.bin };
+  if (files) Object.assign(base, { PREGATE_FILES_FILE: list, PREGATE_TREE: f.tree, PREGATE_SPEND_CAP_USD: '2' });
+  const merged = Object.fromEntries(Object.entries({ ...base, ...env }).filter(([, v]) => v !== undefined)) as Record<string, string>;
+  const r = Bun.spawnSync(['bash', 'scripts/ubicloud/pregate-remote.sh'], { cwd: f.repo, env: merged, timeout: 90_000 });
+  const out = r.stdout.toString() + r.stderr.toString();
+  return { exit: r.exitCode, out, report: parseRemoteReport(out), calls: fs.existsSync(f.calls) ? fs.readFileSync(f.calls, 'utf8').trim().split('\n') : [] };
+}
+const KEY = { UBICLOUD_API_KEY: 'offline-stub' };
+
+describe('pregate-remote.sh inputs and the local tree check', () => {
+  test('run bare it exits 2 before any work, naming the pregate command', () => {
+    const f = fixture();
+    const r = gate(f, null, KEY);
+    expect(r.exit).toBe(2);
+    expect(r.out).toContain('pregate-remote: PREGATE_REMOTE_USAGE: PREGATE_FILES_FILE is not set; run: gstack-pregate --stage tests --remote --spend-cap <usd> --allow-repo-commands');
+    expect(r.out).toContain('see docs/pregate.md#remote-gate');
+    expect(r.calls).toEqual([]);
+    expect(fs.existsSync(path.join(f.repo, '.context'))).toBe(false);
+  }, 60_000);
+
+  test('a working tree that is not PREGATE_TREE exits 3 before any upload, with both prefixes and the rerun command', () => {
+    const f = fixture();
+    const r = gate(f, ['test/alpha.test.ts'], { ...KEY, PREGATE_TREE: 'f'.repeat(40) });
+    expect(r.exit).toBe(3);
+    expect(r.out).toContain(`PREGATE_REMOTE_TREE_MISMATCH: the working tree is ${f.tree.slice(0, 12)}, not the planned tree ffffffffffff`);
+    expect(r.out).toContain('nothing uploaded, nothing spent');
+    expect(r.out).toContain('rerun: gstack-pregate --stage tests --remote --spend-cap <usd> --allow-repo-commands');
+    expect(r.calls).toEqual([]);
+    expect(r.report).toBeNull();
+  }, 60_000);
+});
+
+describe('pregate-remote.sh keyed path (stub ubi-runner)', () => {
+  test('a passing run prints the VM tree, the counts and billed spend; pregate clears it', () => {
+    const f = fixture();
+    const r = gate(f, ['test/alpha.test.ts', 'test/beta.test.ts'], KEY);
+    expect(r.exit, r.out).toBe(0);
+    expect(r.report).toEqual({ tree: f.tree, tests: 2, failed: 0, spent: '0.01' });
+    expect(remoteReportProblem(r.report!, f.tree)).toBeNull();
+    expect(r.out).toContain("2 files on one standard-16 VM; worst case $0.38 under the cap $2; the VM is told to stop after 2520s (the cap's 45 min wall minus 3 min for teardown)");
+    expect(r.out).toMatch(/phases: create \d+s, setup \d+s, run \d+s, teardown \d+s; total \d+s \(target 600s\)/);
+    expect(r.out.trim().split('\n').at(-1)).toMatch(/^PREGATE_REMOTE: /);
+    expect(r.calls).toHaveLength(1);
+    for (const arg of ['-s standard-16 ', '--env GSTACK_EXPECT_BINARIES=1', '--env GSTACK_FREE_RETRY_FLAKY=1', '--env GSTACK_FREE_JOBS=2', '-- bash ~/.pregate-run.sh']) expect(r.calls[0]).toContain(arg);
+    expect(fs.readFileSync(path.join(f.vm, '.pregate-files.txt'), 'utf8')).toBe('test/alpha.test.ts\ntest/beta.test.ts\n');
+  }, 90_000);
+
+  test('setup rebuilding committed build output (as CI does) is printed; the reported tree stays the uploaded one', () => {
+    const f = fixture();
+    const r = gate(f, ['test/alpha.test.ts'], { ...KEY, STUB_SETUP_REBUILD: '1' });
+    expect(r.exit, r.out).toBe(0);
+    expect(r.out).toContain('  setup rebuilt (committed build output, as the CI free lane rebuilds it): M\tdist/bundle.txt');
+    expect(r.report).toEqual({ tree: f.tree, tests: 1, failed: 0, spent: '0.01' });
+  }, 90_000);
+
+  test('a failing test reports failed>0 and exits 1; a file with zero tests reports tests=0; neither clears', () => {
+    const failing = gate(fixture(), ['test/alpha.test.ts', 'test/fails.test.ts'], KEY);
+    expect(failing.exit, failing.out).toBe(1);
+    expect(failing.report).toMatchObject({ tests: 2, failed: 1 });
+    expect(remoteReportProblem(failing.report!, failing.report!.tree)).toBe('the remote gate reported 1 failed of 2');
+    const empty = gate(fixture(), ['test/empty.test.ts'], KEY);
+    expect(empty.report, empty.out).toMatchObject({ tests: 0, failed: 0 });
+    expect(remoteReportProblem(empty.report!, empty.report!.tree)).toBe('the remote gate reported 0 tests');
+  }, 90_000);
+
+  test('the cap refuses before any VM is created, at the price of the size actually used', () => {
+    const f = fixture();
+    const low = gate(f, ['test/alpha.test.ts'], { ...KEY, PREGATE_SPEND_CAP_USD: '0.1' });
+    expect(low.exit).toBe(5);
+    expect(low.out).toContain('PREGATE_REMOTE_CAP_TOO_LOW: worst case $0.17 (20 min x $0.00831/min on standard-16) exceeds the spend cap $0.1');
+    expect(low.out).toContain('nothing created, nothing spent');
+    expect(low.out).toContain('rerun with --spend-cap 0.17 or more');
+    const big = gate(f, ['test/alpha.test.ts'], { ...KEY, PREGATE_SPEND_CAP_USD: '0.5', UBI_SIZE: 'standard-60' });
+    expect(big.exit).toBe(5);
+    expect(big.out).toContain('worst case $0.63 (20 min x $0.03117/min on standard-60) exceeds the spend cap $0.5');
+    const unpriced = gate(f, ['test/alpha.test.ts'], { ...KEY, UBI_SIZE: 'burstable-1' });
+    expect(unpriced.exit).toBe(5);
+    expect(unpriced.out).toContain('PREGATE_REMOTE_NO_PRICE: no price for UBI_SIZE=burstable-1');
+    const noCap = gate(f, ['test/alpha.test.ts'], { ...KEY, PREGATE_SPEND_CAP_USD: '' });
+    expect(noCap.exit).toBe(2);
+    expect([low, big, unpriced, noCap].every(r => r.report === null)).toBe(true);
+    expect(fs.existsSync(f.calls)).toBe(false);
+  }, 90_000);
+
+  test('create, setup and SSH failures exit 4 with the ubi-runner message, the VM, its teardown line, the log and spent=', () => {
+    const create = gate(fixture(), ['test/alpha.test.ts'], { ...KEY, STUB_FAIL: 'create' });
+    expect(create.exit, create.out).toBe(4);
+    expect(create.out).toContain('PREGATE_REMOTE_INFRA: infrastructure failure (ubi-runner exit 1): ubi-runner: create failed');
+    expect(create.out).toMatch(/VM: eu-central-h1\/(ubirun-stub-\d+-[0-9a-f]{8}); ubi-runner: gone: eu-central-h1\/\1 \(never existed or already destroyed\)/);
+    expect(create.out).toMatch(/VM (ubirun-stub-\d+-[0-9a-f]{8}); if this run is killed before its teardown line, destroy it with: bash scripts\/ubicloud\/ubi-runner\.sh down \1\n/);
+    expect(create.out).toMatch(/log: \S+\/\.context\/pregate-remote\/\S+\/run\.log/);
+    expect(create.out).toContain('spent=0.00 (0 billed min on standard-16)');
+    const setup = gate(fixture(), ['test/alpha.test.ts'], { ...KEY, STUB_SETUP_FAIL: '1' });
+    expect(setup.exit, setup.out).toBe(4);
+    expect(setup.out).toContain('ubi-runner: setup failed');
+    expect(setup.out).toMatch(/; ubi-runner: destroyed eu-central-h1\/ubirun-stub-\d+-[0-9a-f]{8}/);
+    expect(setup.out).toContain('spent=0.01 (1 billed min on standard-16)');
+    const ssh = gate(fixture(), ['test/alpha.test.ts'], { ...KEY, STUB_FAIL: 'ssh' });
+    expect(ssh.exit, ssh.out).toBe(4);
+    expect(ssh.out).toContain('infrastructure failure (ubi-runner exit 255): ubi-runner: command exited 255 after 1s');
+    expect([create, setup, ssh].every(r => r.report === null)).toBe(true);
+  }, 90_000);
+
+  test('a quota refusal is retried once, then the run stops', () => {
+    const once = gate(fixture(), ['test/alpha.test.ts'], { ...KEY, STUB_FAIL: 'quota-once', PREGATE_REMOTE_QUOTA_WAIT_S: '0' });
+    expect(once.exit, once.out).toBe(0);
+    expect(once.out).toContain('vCPU quota refused the VM; one retry in 0 s');
+    expect(once.calls).toHaveLength(2);
+    const twice = gate(fixture(), ['test/alpha.test.ts'], { ...KEY, STUB_FAIL: 'quota', PREGATE_REMOTE_QUOTA_WAIT_S: '0' });
+    expect(twice.exit, twice.out).toBe(4);
+    expect(twice.calls).toHaveLength(2);
+    expect(twice.out).toContain('create failed: vCPU quota exhausted');
+  }, 90_000);
+
+  test('the VM refuses a tree that differs after unpack, a planned set that differs from the list, and a tree that moved during the run', () => {
+    const edited = gate(fixture(), ['test/alpha.test.ts'], { ...KEY, STUB_VM_EDIT: 'test/alpha.test.ts' });
+    expect(edited.exit, edited.out).toBe(3);
+    expect(edited.out).toContain('PREGATE_REMOTE_VM_TREE: the VM refused before running tests: PREGATE_VM_TREE_MISMATCH vm=');
+    expect(edited.out).toContain('no tests ran; spent=0.01');
+    const listed = gate(fixture(), ['test/alpha.test.ts'], { ...KEY, STUB_VM_LIST_ADD: 'test/beta.test.ts' });
+    expect(listed.exit, listed.out).toBe(3);
+    expect(listed.out).toContain('PREGATE_VM_PLAN_MISMATCH planned=');
+    const moved = gate(fixture(), ['test/alpha.test.ts', 'test/mover.test.ts'], KEY);
+    expect(moved.exit, moved.out).toBe(3);
+    expect(moved.out).toContain("PREGATE_REMOTE_TREE_MOVED: the VM's tree moved during the run");
+    expect(moved.out).toContain('  moved: A\tmoved.txt');
+    expect([edited, listed, moved].every(r => r.report === null)).toBe(true);
+  }, 90_000);
+
+  test('killing the gate\'s process group (pregate\'s timeout) never cuts teardown short; TERM under an outer deadline tears the VM down; an edit to the script mid-run changes nothing', async () => {
+    const run = (f: Fixture) => {
+      const list = path.join(path.dirname(f.repo), 'files.txt');
+      fs.writeFileSync(list, 'test/alpha.test.ts\n');
+      return Bun.spawn(['bash', 'scripts/ubicloud/pregate-remote.sh'], { cwd: f.repo, detached: true, stdout: 'pipe', stderr: 'pipe',
+        env: { ...process.env, ...KEY, UBI_SIZE: '', GSTACK_FREE_JOBS: '2', STUB_CALLS: f.calls, STUB_VM_HOME: f.vm, STUB_BIN: f.bin, STUB_HANG: '4',
+          PREGATE_FILES_FILE: list, PREGATE_TREE: f.tree, PREGATE_SPEND_CAP_USD: '2', PREGATE_TIMEOUT_S: '900' } as Record<string, string> });
+    };
+    const until = async (cond: () => boolean, ms: number) => {
+      const deadline = Date.now() + ms;
+      while (!cond()) { if (Date.now() > deadline) throw new Error('condition not met in time'); await Bun.sleep(50); }
+    };
+    const vmLog = (f: Fixture) => { try { return fs.readFileSync(fs.readdirSync(path.join(f.repo, '.context/pregate-remote')).map(d => path.join(f.repo, '.context/pregate-remote', d, 'run.log'))[0]!, 'utf8'); } catch { return ''; } };
+    const killed = fixture();
+    const a = run(killed);
+    await until(() => vmLog(killed).includes('ubi-runner: running on'), 30_000);
+    process.kill(-a.pid, 'SIGKILL');
+    await a.exited;
+    await until(() => fs.existsSync(killed.calls + '.down'), 30_000);
+    expect(fs.readFileSync(killed.calls + '.down', 'utf8')).toMatch(/^exit ubirun-stub-\d+-[0-9a-f]{8}\n$/);
+    const termed = fixture();
+    const b = run(termed);
+    await until(() => vmLog(termed).includes('ubi-runner: running on'), 30_000);
+    process.kill(b.pid, 'SIGTERM');
+    expect(await b.exited).toBe(130);
+    expect(await new Response(b.stdout).text()).toContain('interrupted: ubi-runner is tearing the VM down on its own');
+    await until(() => fs.existsSync(termed.calls + '.down'), 10_000);
+    expect(fs.readFileSync(termed.calls + '.down', 'utf8')).toMatch(/^term ubirun-stub-\d+-[0-9a-f]{8}\n$/);
+    const edited = fixture();
+    const c = run(edited);
+    await until(() => vmLog(edited).includes('ubi-runner: running on'), 30_000);
+    const script = path.join(edited.repo, 'scripts/ubicloud/pregate-remote.sh');
+    fs.writeFileSync(script, '#!/usr/bin/env bash\n# an edit that shifts every byte offset\n' + fs.readFileSync(script, 'utf8').split('\n').slice(1).join('\n'));
+    expect(await c.exited).toBe(0);
+    expect((await new Response(c.stdout).text()).trim().split('\n').at(-1)).toMatch(new RegExp(`^PREGATE_REMOTE: tree=${edited.tree} tests=1 failed=0 spent=`));
+  }, 90_000);
+
+  test('an enclosing pregate deadline shorter than the wall sets when the VM is told to stop; one too short refuses before any VM', () => {
+    const f = fixture();
+    const viaEnv = gate(f, ['test/alpha.test.ts'], { ...KEY, PREGATE_TIMEOUT_S: '900' });
+    expect(viaEnv.exit, viaEnv.out).toBe(0);
+    expect(viaEnv.out).toMatch(/the VM is told to stop after (76[0-5])s \(PREGATE_TIMEOUT_S 900s minus 120 s teardown reserve and 15 s margin\)/);
+    const short = gate(f, ['test/alpha.test.ts'], { ...KEY, PREGATE_TIMEOUT_S: '400' });
+    expect(short.exit).toBe(5);
+    expect(short.out).toMatch(/PREGATE_REMOTE_TIMEOUT_TOO_SHORT: PREGATE_TIMEOUT_S 400s leaves 26\ds for the VM after 120 s reserved for teardown and 15 s margin \(at least 300 s needed\)/);
+    expect(short.out).toContain('nothing created, nothing spent');
+    expect(fs.readFileSync(f.calls, 'utf8').trim().split('\n')).toHaveLength(1);
+    // Run under a process named gstack-pregate, the deadline is read from its --timeout (600 s when it passes none).
+    const shim = path.join(path.dirname(f.repo), 'gstack-pregate');
+    fs.writeFileSync(shim, '#!/usr/bin/env bash\nbash scripts/ubicloud/pregate-remote.sh\n', { mode: 0o755 });
+    const run = (args: string[], via = '"$0" "$@"; exit $?') => {
+      const r = Bun.spawnSync(['bash', '-c', via, shim, ...args], { cwd: f.repo, timeout: 90_000, env: { ...process.env, ...KEY, UBI_SIZE: '', GSTACK_FREE_JOBS: '2',
+        STUB_CALLS: f.calls, STUB_VM_HOME: f.vm, STUB_BIN: f.bin, PREGATE_FILES_FILE: path.join(path.dirname(f.repo), 'files.txt'), PREGATE_TREE: f.tree, PREGATE_SPEND_CAP_USD: '2' } as Record<string, string> });
+      return r.stdout.toString() + r.stderr.toString();
+    };
+    expect(run(['--stage', 'tests', '--remote', '--timeout', '1200'])).toMatch(/told to stop after 106[0-5]s \(gstack-pregate --timeout 1200s minus/);
+    expect(run(['--stage', 'tests', '--remote'])).toMatch(/told to stop after 46[0-5]s \(gstack-pregate --timeout 600s minus/);
+    // An ancestor that only mentions gstack-pregate (a shell line running it beside the gate) is not the enclosing pregate.
+    expect(run([], ': bin/gstack-pregate --timeout 400; bash scripts/ubicloud/pregate-remote.sh; exit $?')).toContain("told to stop after 2520s (the cap's 45 min wall minus 3 min for teardown)");
+  }, 120_000);
+
+  test('the VM environment is bun run test:ubicloud\'s (scripts/ubicloud/test-free.sh), so the two cannot drift', () => {
+    const script = fs.readFileSync(path.join(ROOT, 'scripts/ubicloud/pregate-remote.sh'), 'utf8');
+    const wrapper = fs.readFileSync(path.join(ROOT, 'scripts/ubicloud/test-free.sh'), 'utf8');
+    const flags = [...wrapper.matchAll(/--(?:env|pull) "?[^\s"]+(?: [^\s"]+)?/g)].map(m => m[0]).filter(flag => !flag.includes('GSTACK_FREE_JOBS'));
+    expect(flags.length).toBeGreaterThanOrEqual(5);
+    for (const flag of flags) expect(script).toContain(flag);
+    expect(wrapper).toContain('--setup "$here/setup-free-suite.sh"');
+    expect(script).toContain("'bash scripts/ubicloud/setup-free-suite.sh'");
+    expect(wrapper).toContain('xvfb-run -a bun run test:free');
+    expect(script).toContain("'xvfb-run -a bun run test:free --files-from ~/.pregate-files.txt'");
+  });
+});
+
+describe('pregate-remote.sh keyless path', () => {
+  test('without a key it runs the list locally in parallel shards and reports the tree it tested with spent=0', () => {
+    const f = fixture();
+    const r = gate(f, ['test/alpha.test.ts', 'test/beta.test.ts']);
+    expect(r.exit, r.out).toBe(0);
+    expect(r.out).toContain('no UBICLOUD_API_KEY: running 2 files locally in parallel shards');
+    expect(r.out).toMatch(/\nbackend=local \(\d+ cores; not the CI environment\)\nPREGATE_REMOTE: /);
+    expect(r.report).toEqual({ tree: f.tree, tests: 2, failed: 0, spent: '0' });
+    expect(remoteReportProblem(r.report!, f.tree)).toBeNull();
+    expect(fs.existsSync(f.calls)).toBe(false);
+  }, 90_000);
+
+  test('a tree that moves during the local run fails without a report', () => {
+    const r = gate(fixture(), ['test/alpha.test.ts', 'test/mover.test.ts']);
+    expect(r.exit, r.out).toBe(3);
+    expect(r.out).toContain('PREGATE_REMOTE_TREE_MOVED: the working tree moved during the run');
+    expect(r.out).toContain('  moved: A\tmoved.txt');
+    expect(r.report).toBeNull();
+  }, 90_000);
+
+  test('paid test files in the selection are named and left to the paid PR gate; a paid-only selection reports tests=0 and cannot clear', () => {
+    const f = fixture();
+    const paid = ['test/skill-e2e-a.test.ts', 'test/skill-e2e-b.test.ts', 'test/skill-llm-eval.test.ts', 'test/codex-e2e-x.test.ts', 'test/carve-section-loading-y.test.ts', 'test/skill-routing-e2e.test.ts'];
+    const mixed = gate(f, ['test/alpha.test.ts', ...paid]);
+    expect(mixed.exit, mixed.out).toBe(0);
+    expect(mixed.out).toContain('6 paid test file(s) are covered by the paid PR gate, not the free tier: test/skill-e2e-a.test.ts, test/skill-e2e-b.test.ts, test/skill-llm-eval.test.ts, test/codex-e2e-x.test.ts, test/carve-section-loading-y.test.ts ...');
+    expect(mixed.out).toContain('no UBICLOUD_API_KEY: running 1 files locally in parallel shards');
+    expect(mixed.report).toEqual({ tree: f.tree, tests: 1, failed: 0, spent: '0' });
+    const keyed = gate(f, ['test/beta.test.ts', 'test/skill-e2e-a.test.ts'], KEY);
+    expect(keyed.exit, keyed.out).toBe(0);
+    expect(fs.readFileSync(path.join(f.vm, '.pregate-files.txt'), 'utf8')).toBe('test/beta.test.ts\n');
+    const only = gate(f, paid.slice(0, 2));
+    expect(only.exit, only.out).toBe(0);
+    expect(only.out).toContain('PREGATE_REMOTE_PAID_ONLY: every selected file is a paid test file');
+    expect(only.report).toEqual({ tree: f.tree, tests: 0, failed: 0, spent: '0' });
+    expect(remoteReportProblem(only.report!, f.tree)).toBe('the remote gate reported 0 tests');
+  }, 90_000);
+
+  test('a list test-free-shards rejects exits 1 without a report', () => {
+    const r = gate(fixture(), ['test/alpha.test.ts', 'test/missing.test.ts']);
+    expect(r.exit, r.out).toBe(1);
+    expect(r.out).toContain('1 path(s) not in the free planned set: test/missing.test.ts');
+    expect(r.out).toContain('PREGATE_REMOTE_NO_RESULT: test-free-shards exited 1 without a FILES-FROM RESULT line');
+    expect(r.report).toBeNull();
+  }, 90_000);
+});
+
+describe('.gstack/pregate.json declares the remote gate', () => {
+  test('remote_gate is this script, and the config still validates', () => {
+    const { config, errors } = parseConfig(fs.readFileSync(path.join(ROOT, '.gstack/pregate.json'), 'utf8'));
+    expect(errors).toEqual([]);
+    expect(config.remote_gate).toBe('bash scripts/ubicloud/pregate-remote.sh');
+  });
+});