diff --git a/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.i18n.yaml b/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.i18n.yaml
index 78ff70c1c1..929708a328 100644
--- a/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.i18n.yaml
+++ b/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.md
-2026-07-31-coverage-exempt-heavy-suites.md: 1f468a69321b451593a9279cfebc1b457fb08a47
-2026-07-31-coverage-exempt-heavy-suites.zh.md: 7e519f44c8321b6b99c04c6af56c4cfa5b641663
+2026-07-31-coverage-exempt-heavy-suites.md: c587950a4cf6e79180d381e61ade0b274dbed6e7
+2026-07-31-coverage-exempt-heavy-suites.zh.md: 74ab9b1510a1d3eafa2ae56da7667afa817737cd
diff --git a/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.md b/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.md
index 1f468a6932..c587950a4c 100644
--- a/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.md
+++ b/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.md
@@ -30,6 +30,7 @@ A suite contributes to coverage exactly when it executes measured files in-proce
 | All 6 typert generator specs | The generator's own src | Generator src is threshold-excluded as a package (`vitest.config.ts`) — outside the threshold scope to begin with |
 | tools-catalog.spec additionally imports | `typert-registry` and `tool-cordis` src | Each package's own tests cover them fully (verified with focused coverage runs, zero threshold errors) |
 | `scripts/install-lefthook.spec.ts`, `scripts/oxlint-contract.spec.ts`, `scripts/change-scope.spec.ts`, `scripts/translation-pairing-merge.spec.ts` | None — they test `scripts/` sources (never in `coverage.include`) and work by spawning child processes | Nothing to carry |
+| `packages/experimental/webworker-runtime/tests/compile/transform-corpus.spec.ts` | None — it spawns a child process that transforms and imports every built bundle (Node's ESM loader is the oracle) | webworker-runtime src is threshold-excluded as a package (`vitest.config.ts`) — outside the threshold scope to begin with |
 
 ### Membership contract
 
diff --git a/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.zh.md b/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.zh.md
index 7e519f44c8..74ab9b1510 100644
--- a/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.zh.md
+++ b/.agents/notes/implemented/process/2026-07-31-coverage-exempt-heavy-suites.zh.md
@@ -30,6 +30,7 @@ Linux 覆盖率 CI 与原生 Windows CI 在插桩门禁内部使用 [job 内分
 | typert generator 全部 6 个 spec | generator 自身 src | generator src 已整包 threshold-excluded（`vitest.config.ts`），本不在阈值口径内 |
 | 其中 tools-catalog.spec 额外 import | `typert-registry`、`tool-cordis` 的 src | 两包各自的测试独立满覆盖（focused coverage 实测无阈值错误） |
 | `scripts/install-lefthook.spec.ts`、`scripts/oxlint-contract.spec.ts`、`scripts/change-scope.spec.ts`、`scripts/translation-pairing-merge.spec.ts` | 无——被测对象是 `scripts/` 源码（从不在 coverage.include），执行方式是 spawn 子进程 | 无需接 |
+| `packages/experimental/webworker-runtime/tests/compile/transform-corpus.spec.ts` | 无——spawn 子进程对全部已构建 bundle 做 transform 并 import（oracle 是 Node ESM loader） | webworker-runtime src 已整包 threshold-excluded（`vitest.config.ts`），本不在阈值口径内 |
 
 ### 成员资格约定
 
diff --git a/scripts/coverage-exempt.ts b/scripts/coverage-exempt.ts
index eff6ca2b13..a8ea51c6f7 100644
--- a/scripts/coverage-exempt.ts
+++ b/scripts/coverage-exempt.ts
@@ -39,4 +39,13 @@ export const coverageExemptHeavySuites: readonly CoverageExemptSuite[] = [
   { filter: 'scripts/oxlint-contract.spec.ts', exclude: 'scripts/oxlint-contract.spec.ts' },
   { filter: 'scripts/change-scope.spec.ts', exclude: 'scripts/change-scope.spec.ts' },
   { filter: 'scripts/translation-pairing-merge.spec.ts', exclude: 'scripts/translation-pairing-merge.spec.ts' },
+  // Spawns the full-corpus transform gate in a child process (Node's ESM
+  // loader is its oracle), so no measured file executes in-process; the
+  // package src is threshold-excluded in vitest.config.ts. A single
+  // 900s-budget case; running it inside an instrumented partition exceeds
+  // the Windows partition budget under load.
+  {
+    filter: 'packages/experimental/webworker-runtime/tests/compile/transform-corpus.spec.ts',
+    exclude: 'packages/experimental/webworker-runtime/tests/compile/transform-corpus.spec.ts',
+  },
 ]