What causes "⚠️ Could not generate QR code:" in davila7/claude-code-templates?

Verify the `qrcode` package is installed and importable (`node -e "require('qrcode')"`)

⚠️ Could not generate QR code:

Error message

⚠️  Could not generate QR code:

What it means

generateQRCode builds a shareable session QR (rendering the session command to a data-URL image) and warns when QR generation fails, returning { dataUrl: null, command }. The command is still usable, so this degrades to a text-only sharing experience. Failure almost always comes from the underlying qrcode library (invalid input text, unsupported payload) or an encoding/render error.

Source

Thrown at cli-tool/src/session-sharing.js:435

    try {
      // Generate QR code as Data URL (for web display)
      const qrDataUrl = await QRCode.toDataURL(command, {
        errorCorrectionLevel: 'M',
        type: 'image/png',
        width: 300,
        margin: 2,
        color: {
          dark: '#000000',
          light: '#FFFFFF'
        }
      });

      return {
        dataUrl: qrDataUrl,
        command: command
      };
    } catch (error) {
      console.warn(chalk.yellow('⚠️  Could not generate QR code:'), error.message);
      return {
        dataUrl: null,
        command: command
      };
    }
  }

  /**
   * Sanitize project name for directory usage
   * @param {string} projectName - Original project name
   * @returns {string} Sanitized name
   */
  sanitizeProjectName(projectName) {
    // Replace spaces and special chars with hyphens
    return projectName
      .replace(/[^a-zA-Z0-9-_]/g, '-')
      .replace(/-+/g, '-')
      .toLowerCase();

View on GitHub (pinned to a0851ed10c)

Solutions

Verify the `qrcode` package is installed and importable (`node -e "require('qrcode')"`)
Shorten the encoded payload (share a URL/short code instead of the full command) and re-run
Pin or upgrade qrcode to a known-good version (`npm i qrcode@^1.5.x`)
Fall back to the returned `command` string — copy/paste sharing still works without the QR

Example fix

// before
const qr = await generateQRCode(veryLongCommand);
// after
const qr = await generateQRCode(command);
if (!qr.dataUrl) {
  console.log('Copy this command instead:', qr.command);
}

Defensive patterns

Strategy: fallback

Validate before calling

if (typeof command !== 'string' || command.length === 0 || command.length > 2000) {
  // skip QR, use text-only sharing
  return { dataUrl: null, command };
}

Try / catch

catch (error) {
  return { dataUrl: null, command }; // always fall back to the plain command
}

Prevention

Keep the encoded payload short (short codes/URLs, not full tokens)
Lock the qrcode dependency version in package.json
Always render a copyable command alongside the QR so sharing works without it

When it happens

Trigger: Calling generateQRCode when the command string to encode is empty or too long for a QR code, when the qrcode dependency is missing or an incompatible version, or when toDataURL options are misconfigured (bad errorCorrectionLevel/format).

Common situations: Session token or command string grew beyond QR capacity (~2-3KB); qrcode package not installed after a partial npm install; running in an environment where the QR renderer's optional native deps are unavailable.

Related errors

AI-assisted analysis of davila7/claude-code-templates@a0851ed10c (2026-08-28). Data as JSON: /api/errors/7d3d89e837c2b381. Report an issue: GitHub.