mastra-ai/mastra · error

Failed to write scorer

Error message

Failed to write scorer: ${errorMessage}

What it means

`writeScorer` wraps any failure from fs.writeFileSync when saving the generated scorer file. The underlying OS error (EACCES, ENOSPC, EISDIR, etc.) is embedded in the message. The directory was created successfully but the file write itself failed.

Solutions

1. Fix write permissions on the scorers directory or existing file
2. Check that the destination path is not a directory
3. Free disk space if the message includes ENOSPC
4. Run the command as a user with access to the project directory

import { accessSync, constants, existsSync, statSync } from 'node:fs';
if (existsSync(target)) {
  if (!statSync(target).isFile()) throw new Error(`${target} is not a regular file`);
}
accessSync(scorersPath, constants.W_OK);

const writableTarget = (dir: string, name: string): boolean => {
  try { accessSync(dir, constants.W_OK); return true; } catch { return false; }
};

try {
  await writeScorer({ ... });
} catch (e) {
  const msg = (e as Error).message;
  if (msg.startsWith('Failed to write scorer')) {
    console.error('Write failed (permissions/disk/path):', msg);
  } else throw e;
}

When it happens

Trigger: fs.writeFileSync fails after the directory check — target path is read-only, path is actually a directory, out of space, or permission denied on the existing file.

Common situations: An existing scorer file is owned by root/read-only; the target filename is a directory; quota or disk-full conditions.

Understand the failure class

Background: "Permission denied" / "Failed to write" file errors: why a library can't write its files to disk (EACCES, EPERM, ENOSPC) and how to fix them — this error's family across 43 libraries.

Related errors

• Failed to create directory
• A file or directory named
• Could not read file
• Directory not found: .
• Directory already exists

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/e4a3c6a27b414b37. Report an issue: GitHub.

Appendix: source

Thrown at packages/cli/src/commands/scorers/file-utils.ts:34

    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      throw new Error(`Failed to create directory: ${errorMessage}`);
    }
  }

  const filePath = path.join(fullPath, filename);

  if (fs.existsSync(filePath)) {
    throw new Error(`Skipped: Scorer ${filename} already exists at ${scorersPath}`);
  }

  try {
    fs.writeFileSync(filePath, content);

    return { ok: true, message: `Created scorer at ${path.relative(rootDir, filePath)}` };
  } catch (error) {
    const errorMessage = error instanceof Error ? error.message : String(error);
    throw new Error(`Failed to write scorer: ${errorMessage}`);
  }
}

View on GitHub (pinned to 75dd419e61)