janhq/jan · error · Error

Failed to parse archive name: ${archiveName}. Expected forma

Error message

Failed to parse archive name: ${archiveName}. Expected format: [Optional prefix-]llama-<version>-bin-<backend>.(tar.gz|zip)

What it means

After confirming the archive path is valid, the archive's basename is tested against a regex that expects the naming convention [prefix-]llama-<version>-bin-<backend>.(tar.gz|zip). If the regex does not match, the extension cannot determine the version and backend identifier from the filename.

Source

Thrown at extensions/llamacpp-extension/src/index.ts:2865

    // - llama-b7037-bin-win-cuda-12.4-x64.zip (legacy format)
    const re =
      /^(.+?[-_])?llama(?:-main)?-(b\d+(?:-[a-f0-9]+)?)(?:-cudart-llama)?-bin-(.+?)\.(?:tar\.gz|zip)$/

    const archiveName = await basename(path)
    logger.info(`Installing backend from path: ${path}`)

    if (
      !(await fs.existsSync(path)) ||
      (!path.endsWith('tar.gz') && !path.endsWith('zip'))
    ) {
      logger.error(`Invalid path or file ${path}`)
      throw new Error(`Invalid path or file ${path}`)
    }

    const match = re.exec(archiveName)

    if (!match) {
      throw new Error(
        `Failed to parse archive name: ${archiveName}. Expected format: [Optional prefix-]llama-<version>-bin-<backend>.(tar.gz|zip)`
      )
    }

    const [, prefix, version, backend] = match

    if (!version || !backend) {
      throw new Error(`Invalid backend archive name: ${archiveName}`)
    }

    // Include prefix in the backend identifier if present
    const backendIdentifier = prefix ? `${prefix}${backend}` : backend

    logger.info(
      `Detected prefix: ${prefix || 'none'}, version: ${version}, backend: ${backendIdentifier}`
    )

    const backendDir = await getBackendDir(backendIdentifier, version)

View on GitHub (pinned to fad3f12a14)

Solutions

1. Use an archive from the official llama.cpp / Jan release that follows the expected naming convention.
2. If using a custom build, rename the archive to match: [prefix-]llama-<version>-bin-<backend>.zip or .tar.gz.
3. If the upstream convention changed, update the regex in the source to match the new pattern.

Example fix

// before (filename: my-custom-build.zip)
// after (rename to: llama-b1234-bin-win-cuda-12.4-x64.zip)

const BACKEND_ARCHIVE_RE = /^(.+?[-_])?llama(?:-main)?-(b\d+(?:-[a-f0-9]+)?)(?:-cudart-llama)?-bin-(.+?)\.(?:tar\.gz|zip)$/

function matchesBackendNaming(archiveName: string): boolean {
  return BACKEND_ARCHIVE_RE.test(archiveName)
}

// Before calling install:
if (!matchesBackendNaming(archiveName)) {
  throw new Error(`Archive name does not match expected convention: ${archiveName}`)
}

function isBackendArchiveName(name: string): boolean {
  return /^(.+?[-_])?llama(?:-main)?-(b\d+(?:-[a-f0-9]+)?)(?:-cudart-llama)?-bin-(.+?)\.(?:tar\.gz|zip)$/.test(name)
}

When it happens

Trigger: The archive filename does not follow the llama.cpp release naming convention. Examples: 'mybackend.zip', 'llama-b1234-bin-win-x64.7z' (wrong extension caught earlier but also wrong here), 'custom-build-v2.tar.gz', a renamed upstream file.

Common situations: User downloaded a custom or community build with a different naming scheme; user renamed the archive; the upstream naming convention changed in a new release and this regex was not updated.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Invalid backend archive name: ${archiveName}
• Invalid path or file ${path}
• Not a supported backend archive! Missing llama-server binary
• Invalid backend string: ${targetBackendString} supplied to u
• Invalid backend string format: "${targetBackendString}". Exp

AI-assisted analysis of janhq/jan@fad3f12a14 (2026-08-12). Data as JSON: /api/errors/a2f634cdc90b3506. Report an issue: GitHub.