vercel/ai · error · Error

ACP skill directory ${JSON.stringify(rootDir)} must be outsi

Error message

ACP skill directory ${JSON.stringify(rootDir)} must be outside sessionWorkDir ${JSON.stringify(sessionWorkDir)}.

What it means

Error "ACP skill directory ${JSON.stringify(rootDir)} must be outside sessionWorkDir ${JSON.stringify(sessionWorkDir)}." thrown in vercel/ai.

Source

Thrown at packages/harness-acp/src/v1/acp-v1-skills.ts:190

      )}: expected a relative POSIX path without traversal.`,
    );
  }
  return normalizedPath;
}

function assertOutsideSessionWorkDir({
  rootDir,
  sessionWorkDir,
}: {
  rootDir: string;
  sessionWorkDir: string;
}): void {
  const relative = path.posix.relative(sessionWorkDir, rootDir);
  const isInside =
    relative === '' ||
    (!relative.startsWith('../') && !path.posix.isAbsolute(relative));
  if (isInside) {
    throw new Error(
      `ACP skill directory ${JSON.stringify(rootDir)} must be outside sessionWorkDir ${JSON.stringify(
        sessionWorkDir,
      )}.`,
    );
  }
}

View on GitHub (pinned to 69428b1f8b)

When it happens

Trigger: Thrown at packages/harness-acp/src/v1/acp-v1-skills.ts:190 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/ai@69428b1f8b (2026-08-30). Data as JSON: /api/errors/111bf17d0c1c1bb4. Report an issue: GitHub.