diff --git a/packages/blocks-react/src/type-surface.test.ts b/packages/blocks-react/src/type-surface.test.ts
index 766caaa740..a25d94663f 100644
--- a/packages/blocks-react/src/type-surface.test.ts
+++ b/packages/blocks-react/src/type-surface.test.ts
@@ -30,8 +30,11 @@
  * `turbo.json` makes `test` depend on `build` and names `dist/**` among its
  * inputs, so an edit anywhere in the declaration's own inputs — this package's
  * sources, the engine's, the bundler config — rebuilds and re-runs. Global
- * setup adds one build before collection so a direct `vitest run` on a tree
- * with no `dist` works at all.
+ * setup does NOT build: it refuses to start when the declarations are missing,
+ * naming the command to run, because a build launched from inside collection
+ * rebuilds this package's whole dependency tree while sibling suites are
+ * importing from it. So a direct `vitest run` on a tree with no `dist` stops
+ * with one legible error rather than racing.
  *
  * Neither covers `vitest --watch`, and deliberately so. Vitest selects a suite
  * from its MODULE GRAPH, which cannot see a `.d.ts` read off disk; making it
@@ -176,7 +179,16 @@ function resolveDeclaration(
   ]) {
     if (existsSync(candidate)) return candidate;
   }
-  return undefined;
+  // A relative specifier inside an emitted declaration names another emitted
+  // declaration. Finding none means the artifact is INCOMPLETE — a build stopped
+  // after writing the entries and before their chunks — and returning
+  // `undefined` would walk a smaller graph, derive fewer required types, and
+  // read as a clean pass. Under-reporting the obligation is the one answer this
+  // suite must never give, so an unresolvable reference stops the run.
+  throw new Error(
+    `${specifier} is referenced by ${from} and no declaration for it exists. ` +
+      `These declarations are incomplete; rebuild before asserting against them.`
+  );
 }
 
 /**
diff --git a/packages/blocks-react/turbo.json b/packages/blocks-react/turbo.json
index 62f53ce1b5..571ccfa5a8 100644
--- a/packages/blocks-react/turbo.json
+++ b/packages/blocks-react/turbo.json
@@ -11,18 +11,21 @@
       // suite either finds no `dist` at all or reads declarations produced
       // before the source change.
       //
-      // This makes turbo do that build, in order, and cache it. It is not the
-      // only guarantee: `vitest.global-setup.ts` builds too, so the entry
-      // points turbo never sees are covered as well.
+      // This makes turbo do that build, in order, and cache it. It is the ONLY
+      // thing that builds them: `vitest.global-setup.ts` refuses to start when
+      // the declarations are missing rather than producing them, because a
+      // build launched from inside collection rebuilds this package's whole
+      // dependency tree while sibling suites are importing from it.
       "dependsOn": ["$TURBO_EXTENDS$", "build"],
       // `$TURBO_EXTENDS$` keeps the root inputs in sync rather than restating
       // them; `dist/**` is appended because the artifact these suites assert
       // against is a real input to them, and a cached pass that ignored it
       // would survive a change to what the bundler emits.
-      // `vitest.global-setup.ts` is named because it IS the build precondition
-      // these suites rely on: a change to it changes what they assert against,
-      // and the root inputs cover `vitest.config.ts` alone — so without it a
-      // cached pass survives an edit to the setup and the run never happens.
+      // `vitest.global-setup.ts` is named because it decides whether these
+      // suites run at all: a change to what it accepts changes whether a given
+      // tree is allowed to assert anything, and the root inputs cover
+      // `vitest.config.ts` alone — so without it a cached pass survives an edit
+      // to the setup and the run never happens.
       "inputs": [
         "$TURBO_EXTENDS$",
         "dist/**",
diff --git a/packages/blocks-react/vitest.global-setup.ts b/packages/blocks-react/vitest.global-setup.ts
index 64cb4b6d0f..deab27ba86 100644
--- a/packages/blocks-react/vitest.global-setup.ts
+++ b/packages/blocks-react/vitest.global-setup.ts
@@ -1,71 +1,81 @@
-import { execFileSync } from "node:child_process";
-import { dirname, join } from "node:path";
+import { existsSync, readFileSync } from "node:fs";
+import { dirname, join, resolve } from "node:path";
 import { fileURLToPath } from "node:url";
 
 /**
- * Build this package before any suite is COLLECTED.
+ * Refuse to start when this package's declarations are missing, rather than
+ * building them.
  *
  * Several suites here assert against the BUILT declarations rather than the
  * source, because the questions they ask — what an entry exports, what a
- * consumer can resolve — have answers only in the emitted artifact. A `dist`
- * that is absent fails them at import time and a `dist` that merely predates
- * the source certifies a surface nobody has.
+ * consumer can resolve — have answers only in the emitted artifact. So a `dist`
+ * that is absent has to stop the run.
  *
- * **Global setup, because collection is concurrent.** Sibling suites import
- * this package while any one suite's own hook would still be building, so on a
- * tree with no `dist` they fail to resolve before that build finishes. Only a
- * stage that completes before collection starts covers them.
+ * **Stopping is all it does, and that is the whole design.** Freshness belongs
+ * to the build system: `turbo.json` makes `test` depend on this package's own
+ * `build` and names `dist/**` among its inputs, so an edit to anything the
+ * declarations are emitted from rebuilds and re-runs. `pnpm test`, `turbo run
+ * test` and CI all arrive through that edge with the artifact already current.
+ * What is checked here is the path that bypasses it — a direct `vitest`, or
+ * `pnpm --filter @nextlyhq/blocks-react test`, which runs the package script
+ * without turbo's graph.
  *
- * It runs ONCE per process, which is the whole of what it guarantees: the
- * declarations are current when the run begins. Keeping them current as inputs
- * change is Turbo's job — `test` depends on `build` and names `dist/**` among
- * its inputs — and a `--watch` session is explicitly outside both, because
- * Vitest selects suites from a module graph that cannot see a `.d.ts` read off
- * disk.
+ * Building here as well looked like belt-and-braces and was not. `turbo run
+ * build --filter=@nextlyhq/blocks-react` carries the `^build` edge, so it
+ * rebuilds this package's whole dependency tree — the engine, the adapters,
+ * `nextly` — and each of those bundles with `clean: true`, deleting its `dist`
+ * before emitting. Run from global setup, that happens DURING collection, while
+ * sibling packages' suites are already importing from those same directories.
+ * A concurrent run then fails in whichever package was mid-import, with a
+ * missing chunk in code nobody changed. One package's convenience cannot be
+ * bought by deleting another package's build output underneath it.
  *
- * Unconditional, with no attempt to detect a build that already happened. The
- * signals available say a Turbo task is running, never that it was one
- * carrying this package's build edge, and a precondition derived from a nearby
- * signal is wrong silently. Where the build did already run this is a cache
- * hit costing milliseconds.
+ * **Absent is checked; STALE is not, and cannot usefully be.** A `dist` older
+ * than the source it describes would pass here and let the suites read an
+ * artifact that agrees with itself while the source has moved. Modification
+ * times cannot close that: Turbo restores a cached `dist` with the timestamp of
+ * the restore, so any later touch of a source file — a checkout, a branch
+ * switch, a formatter — makes the source newer than an artifact whose content is
+ * current. Measured on this package: a cache-restored `dist/index.d.ts` at
+ * `…57.173` against an unchanged `src/index.ts` at `…57.691`. A timestamp guard
+ * would refuse to run on a correct tree, which is a worse failure than the rare
+ * one it prevents, and deciding freshness exactly means re-implementing Turbo's
+ * hashing. Turbo stays the authority, through the `test` -> `build` edge.
  *
- * Through Turbo rather than `tsup` directly: the declaration build resolves
- * `@nextlyhq/blocks-engine`, so invoking the bundler on a tree where that
- * dependency has not been built fails before any declarations exist. `turbo
- * run build` carries the `^build` edge, so the dependency is built first.
+ * The entries are read from `package.json` rather than listed here, so this
+ * checks exactly what the suites resolve and cannot drift from it as entries
+ * are added.
  */
 export default function setup(): void {
-  const repoRoot = join(dirname(fileURLToPath(import.meta.url)), "..", "..");
+  const packageRoot = dirname(fileURLToPath(import.meta.url));
+  const manifest = JSON.parse(
+    readFileSync(join(packageRoot, "package.json"), "utf8")
+  ) as { name?: string; exports?: Record<string, { types?: string }> };
+  const name = manifest.name ?? "@nextlyhq/blocks-react";
+  // Scoped through `turbo run` directly rather than the root `build` script,
+  // which already carries `--filter=./packages/*`. Turbo's filters are
+  // ADDITIVE, so `pnpm build --filter <name>` selects 23 package builds rather
+  // than this one's subtree — advice that would clean unrelated packages' `dist`
+  // is the behaviour this file exists to stop recommending.
+  const recovery = `pnpm exec turbo run build --filter=${name}`;
 
-  try {
-    execFileSync(
-      "pnpm",
-      ["exec", "turbo", "run", "build", "--filter=@nextlyhq/blocks-react"],
-      {
-        cwd: repoRoot,
-        stdio: "pipe",
-        // Windows resolves package-manager shims via the shell: Corepack
-        // installs `pnpm.cmd`, which cannot be launched directly. Matches how
-        // the CLI spawns a package manager in `cli/commands/add.ts`.
-        shell: process.platform === "win32",
-      }
-    );
-  } catch (error) {
-    // Compiler diagnostics are the only thing that makes a failure here
-    // actionable, and a discarded stream reduces every cause to the same
-    // opaque non-zero exit.
-    const output = `${streamText(error, "stdout")}${streamText(error, "stderr")}`;
+  const declarations = Object.entries(manifest.exports ?? {})
+    .map(([subpath, entry]) => ({ subpath, types: entry?.types }))
+    .filter(
+      (entry): entry is { subpath: string; types: string } =>
+        typeof entry.types === "string"
+    )
+    .map(entry => ({ ...entry, file: resolve(packageRoot, entry.types) }));
+
+  const missing = declarations
+    .filter(entry => !existsSync(entry.file))
+    .map(entry => `${entry.subpath} (${entry.types})`);
+  if (missing.length > 0) {
     throw new Error(
-      `building @nextlyhq/blocks-react failed:\n${output.trim()}`
+      `${name} has no built declarations for ${missing.join(", ")}.\n` +
+        `Several suites here assert against the emitted artifact, so there is ` +
+        `nothing for them to read.\n` +
+        `Run \`${recovery}\`, or use \`pnpm test\` / \`turbo run test\`, which build first.`
     );
   }
 }
-
-/** `stdout`/`stderr` off a failed `execFileSync`, without assuming its shape. */
-function streamText(error: unknown, key: "stdout" | "stderr"): string {
-  if (typeof error !== "object" || error === null || !(key in error)) return "";
-  const value: unknown = Reflect.get(error, key);
-  if (typeof value === "string") return value;
-  if (value instanceof Uint8Array) return Buffer.from(value).toString("utf8");
-  return "";
-}