diff --git a/.changeset/tidy-lexicon-links.md b/.changeset/tidy-lexicon-links.md
new file mode 100644
index 0000000..741ec48
--- /dev/null
+++ b/.changeset/tidy-lexicon-links.md
@@ -0,0 +1,5 @@
+---
+"@atmo-dev/contrail": patch
+---
+
+Run Atcute's Lexicon CLI with an explicit module redirect for its byte-array helper so `contrail dev` works with pnpm's strictly isolated global package links.
diff --git a/packages/contrail/src/cli/atcute.ts b/packages/contrail/src/cli/atcute.ts
index a02539e..93fcbf5 100644
--- a/packages/contrail/src/cli/atcute.ts
+++ b/packages/contrail/src/cli/atcute.ts
@@ -1,9 +1,35 @@
 import { spawnSync } from "node:child_process";
 import { createRequire } from "node:module";
 import { dirname, join } from "node:path";
+import { pathToFileURL } from "node:url";
 
 const require = createRequire(import.meta.url);
 
+function dataModule(source: string): string {
+  return `data:text/javascript,${encodeURIComponent(source)}`;
+}
+
+/** Create a preload module that redirects one bare import before starting a
+ * child CLI. This keeps undeclared transitive imports working in package
+ * managers whose content-addressed links fully isolate dependency trees. */
+export function createModuleRedirectRegistration(
+  specifier: string,
+  targetUrl: string,
+): string {
+  const loader = dataModule(
+    `export async function resolve(specifier, context, nextResolve) {
+  if (specifier === ${JSON.stringify(specifier)}) {
+    return { url: ${JSON.stringify(targetUrl)}, shortCircuit: true };
+  }
+  return nextResolve(specifier, context);
+}`,
+  );
+  return dataModule(
+    `import { register } from "node:module";
+register(${JSON.stringify(loader)}, import.meta.url);`,
+  );
+}
+
 function runAtcute(
   action: "pull" | "generate",
   root: string,
@@ -11,9 +37,22 @@ function runAtcute(
 ): void {
   const entry = require.resolve("@atcute/lex-cli");
   const cli = join(dirname(entry), "..", "cli.mjs");
+  // @atcute/lex-cli 3.3.0 imports this helper but declares it only as a dev
+  // dependency. Resolve Contrail's declared copy explicitly until upstream's
+  // package metadata includes it as a runtime dependency.
+  const registration = createModuleRedirectRegistration(
+    "@atcute/uint8array",
+    pathToFileURL(require.resolve("@atcute/uint8array")).href,
+  );
   const result = spawnSync(
     process.execPath,
-    [cli, action, ...(configPath ? ["--config", configPath] : [])],
+    [
+      "--import",
+      registration,
+      cli,
+      action,
+      ...(configPath ? ["--config", configPath] : []),
+    ],
     {
       cwd: root,
       stdio: "inherit",
diff --git a/packages/contrail/tests/atcute-cli.test.ts b/packages/contrail/tests/atcute-cli.test.ts
new file mode 100644
index 0000000..0d7cc08
--- /dev/null
+++ b/packages/contrail/tests/atcute-cli.test.ts
@@ -0,0 +1,44 @@
+import { spawnSync } from "node:child_process";
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { pathToFileURL } from "node:url";
+import { afterEach, describe, expect, it } from "vitest";
+import { createModuleRedirectRegistration } from "../src/cli/atcute";
+
+const roots: string[] = [];
+
+afterEach(() => {
+  for (const root of roots.splice(0)) {
+    rmSync(root, { recursive: true, force: true });
+  }
+});
+
+describe("Atcute CLI module resolution", () => {
+  it("redirects an undeclared bare import in an isolated child process", () => {
+    const root = mkdtempSync(join(tmpdir(), "contrail-atcute-loader-"));
+    roots.push(root);
+    const target = join(root, "target.mjs");
+    const entry = join(root, "entry.mjs");
+    writeFileSync(target, `export const value = "resolved";\n`);
+    writeFileSync(
+      entry,
+      `import { value } from "@missing/runtime-helper";
+process.stdout.write(value);
+`,
+    );
+
+    const registration = createModuleRedirectRegistration(
+      "@missing/runtime-helper",
+      pathToFileURL(target).href,
+    );
+    const result = spawnSync(
+      process.execPath,
+      ["--import", registration, entry],
+      { encoding: "utf8" },
+    );
+
+    expect(result.status, result.stderr).toBe(0);
+    expect(result.stdout).toBe("resolved");
+  });
+});