diff --git a/.forgejo/workflows/acceptance.yml b/.forgejo/workflows/acceptance.yml
index 73e0d32..cc5cbb2 100644
--- a/.forgejo/workflows/acceptance.yml
+++ b/.forgejo/workflows/acceptance.yml
@@ -40,12 +40,15 @@ jobs:
         shell: bash
         run: |
           node --version && bun --version
+          bun install --frozen-lockfile
           bun tools/acceptance.ts run --runtime ${{ matrix.runtime }} --platform Linux --jobs 4 --out acceptance/Linux-${{ matrix.name }}.json
       - name: Acceptance matrix (Windows)
         if: ${{ matrix.platform == 'Windows' }}
         shell: pwsh
         run: |
           node --version; bun --version
+          bun install --frozen-lockfile
+          if ($LASTEXITCODE -ne 0) { throw "bun install failed" }
           bun tools/acceptance.ts run --runtime ${{ matrix.runtime }} --platform Windows --jobs 3 --out acceptance/Windows-${{ matrix.name }}.json
           if ($LASTEXITCODE -ne 0) { throw "acceptance matrix: red cells" }
       - uses: actions/upload-artifact@v3
diff --git a/.forgejo/workflows/ci.yml b/.forgejo/workflows/ci.yml
index 71bbfd7..e37e533 100644
--- a/.forgejo/workflows/ci.yml
+++ b/.forgejo/workflows/ci.yml
@@ -106,12 +106,17 @@ jobs:
         shell: bash
         run: |
           node --version && bun --version
+          # npm pack runs prepack, which builds the package's declarations with the pinned TypeScript
+          bun install --frozen-lockfile
           bun tools/acceptance.ts run --runtime ${{ matrix.runtime }} --platform Linux --jobs 4 --out acceptance/Linux-${{ matrix.name }}.json
       - name: Acceptance matrix (Windows)
         if: ${{ matrix.platform == 'Windows' }}
         shell: pwsh
         run: |
           node --version; bun --version
+          # npm pack runs prepack, which builds the package's declarations with the pinned TypeScript
+          bun install --frozen-lockfile
+          if ($LASTEXITCODE -ne 0) { throw "bun install failed" }
           bun tools/acceptance.ts run --runtime ${{ matrix.runtime }} --platform Windows --jobs 3 --out acceptance/Windows-${{ matrix.name }}.json
           if ($LASTEXITCODE -ne 0) { throw "acceptance matrix: red cells" }
       - uses: actions/upload-artifact@v3
diff --git a/tools/build-node.ts b/tools/build-node.ts
index 996e32f..586d863 100644
--- a/tools/build-node.ts
+++ b/tools/build-node.ts
@@ -41,6 +41,7 @@ export function buildNode(out = NODE_BUNDLE): { path: string; bytes: number } {
 export function buildEntry(dir = join(ROOT, 'dist')): void {
   const types = join(dir, 'types');
   rmSync(types, { recursive: true, force: true });
+  if (!statSync(join(ROOT, 'node_modules', '.bin', 'tsc'), { throwIfNoEntry: false })) throw new Error('no TypeScript in node_modules: run `bun install` first (npm pack builds the declarations with it)');
   const tsc = Bun.spawnSync([join(ROOT, 'node_modules', '.bin', 'tsc'), '-p', 'tsconfig.types.json', '--outDir', types], { cwd: ROOT, stdout: 'pipe', stderr: 'pipe' });
   if (tsc.exitCode !== 0) throw new Error(`tsc (declarations) failed\n${tsc.stdout.toString()}${tsc.stderr.toString()}`);
   if (!statSync(join(types, 'lib', 'config.d.ts'), { throwIfNoEntry: false })) throw new Error('no dist/types/lib/config.d.ts');