astro pre-render error: Astro2.locals.auth is not a function

[jphat]

Preliminary Checks

• I have reviewed the documentation: https://clerk.com/docs

• I have searched for existing issues: https://github.com/clerk/javascript/issues

• I have not already reached out to Clerk support via email or Discord (if you have, no need to open an issue here)

• This issue is not a question, general help request, or anything other than a bug report directly related to Clerk. Please ask questions in our Discord community: https://clerk.com/discord.

Reproduction

https://github.com/jphat/clerk-astro

Publishable key

pk_test_dXAtbWl0ZS01MS5jbGVyay5hY2NvdW50cy5kZXYk

Description

Steps to reproduce:

1. bun install
2. bun run dev
3. go to a pre-rendered blog page: http://localhost:4321/posts/post-1/

Expected behavior:

View blog page

Actual behavior:

without adding pre-render, I get this error
[WARN] [router] getStaticPaths() ignored in dynamic page /src/pages/posts/[...slug].astro. Add export const prerender = true; to prerender the page as static HTML during the build process

adding pre-render, I get this error
[ERROR] Astro2.locals.auth is not a function Stack trace: at /Users/josephat.1/Documents/Projects/clerk-astro-quickstart/node_modules/@clerk/astro/components/control/SignedOutSSR.astro:2:33 [...] See full stack trace in the browser, or rerun with --verbose.

Environment

System:
    OS: macOS 26.2
    CPU: (12) arm64 Apple M3 Pro
    Memory: 269.61 MB / 18.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    bun: 1.3.5 - /Users/.../.bun/bin/bun
  Browsers:
    Brave Browser: 144.1.86.139
    Chrome: 144.0.7559.60
    Edge: 143.0.3650.80
    Firefox: 147.0
    Safari: 26.2
  npmPackages:
    @astrojs/check: ^0.9.4 => 0.9.6 
    @astrojs/node: ^9.5.1 => 9.5.1 
    @clerk/astro: ^2.13.6 => 2.16.12 
    @types/bun: latest => 1.3.6 
    astro: ^5.14.1 => 5.16.9 
    prettier: ^3.6.2 => 3.8.0 
    prettier-plugin-astro: ^0.14.1 => 0.14.1 
    typescript: ^5.9.3 => 5.9.3