What causes "The CCR artifact endpoint attempted a redirect." in musistudio/claude-code-router?

Identify what is redirecting: fetch the URL manually with curl -v and inspect for 3xx or Location headers

The CCR artifact endpoint attempted a redirect.

Error message

The CCR artifact endpoint attempted a redirect.

What it means

Even though fetch was configured with redirect: 'error' (which normally makes redirects throw and produce error 50), some runtimes/servers can still yield a response flagged as redirected (e.g. non-standard redirect handling or a transparent proxy rewrite). This defensive check rejects any response whose final URL differs from the requested one.

Source

Thrown at packages/core/src/agents/codex/media-preview-bridge.ts:305

  if (keys.length !== 1 || keys[0] !== "token" || !/^[A-Za-z0-9_-]{32}$/.test(token)) {
    throw new Error("Artifact URL contains an invalid access token.");
  }
  return { artifactId, url };
}

async function loadCodexMediaArtifact(validated: ValidatedArtifactUrl, signal: AbortSignal): Promise<LoadedMediaArtifact> {
  let response: Response;
  try {
    response = await fetch(validated.url, {
      headers: { accept: "image/*, video/*" },
      redirect: "error",
      signal
    });
  } catch {
    throw new Error("The CCR artifact request failed.");
  }
  if (!response.ok) throw new Error(`The CCR artifact endpoint returned HTTP ${response.status}.`);
  if (response.redirected) throw new Error("The CCR artifact endpoint attempted a redirect.");
  const declaredMimeType = (response.headers.get("content-type") || "").split(";", 1)[0].trim().toLowerCase();
  const declaredKind = mediaKind(declaredMimeType);
  if (!declaredKind) throw new Error("The CCR artifact endpoint returned a non-media content type.");
  const maxBytes = declaredKind === "video" ? codexMediaPreviewMaxVideoBytes : codexMediaPreviewMaxImageBytes;
  const declaredLength = Number(response.headers.get("content-length") || "0");
  if (declaredLength && (!Number.isSafeInteger(declaredLength) || declaredLength < 1 || declaredLength > maxBytes)) {
    throw new Error("The CCR media artifact exceeds the inline preview size limit.");
  }
  if (response.headers.get("content-encoding") && response.headers.get("content-encoding") !== "identity") {
    throw new Error("Compressed CCR media artifacts are not accepted for inline preview.");
  }
  if (!response.body) throw new Error("The CCR artifact response had no body.");
  const reader = response.body.getReader();
  const chunks: Buffer[] = [];
  let total = 0;
  while (true) {
    const part = await reader.read();
    if (part.done) break;

View on GitHub (pinned to 99f24806c6)

Solutions

Identify what is redirecting: fetch the URL manually with curl -v and inspect for 3xx or Location headers
Bypass or configure the proxy so the artifact URL is served directly
Ensure the runtime's fetch honors redirect: 'error' (upgrade Node >= 18 native fetch rather than a polyfill)
Use the final canonical URL of the artifact in the reference

Defensive patterns

Strategy: validation

Validate before calling

// Verify the URL serves directly without a redirect before calling artifact()
async function isRedirectFree(url: string): Promise<boolean> {
  const res = await fetch(url, { method: 'HEAD', redirect: 'error' });
  return !res.redirected;
}

Type guard

function isRedirectRejection(e: unknown): boolean {
  return e instanceof Error && e.message.includes('attempted a redirect');
}

Try / catch

try {
  const media = await bridge.artifact(ref);
} catch (e) {
  if (isRedirectRejection(e)) return renderAsExternalLink(ref.url);
  throw e;
}

Prevention

Store canonical, non-redirecting artifact URLs
Avoid proxies that rewrite/redirect media requests
Use native fetch implementations that honor redirect: 'error'

When it happens

Trigger: An intercepting proxy or service mesh silently rewrites the request to a different origin; a runtime whose fetch implementation follows redirects despite redirect: 'error'; an HTTP/2 server responding from a redirected location.

Common situations: Corporate proxies, local dev proxies (e.g. mitmproxy), or PaaS ingress layers that redirect artifact URLs; polyfilled fetch implementations (node-fetch versions with different redirect semantics) that follow redirects before the option is honored.

Related errors

AI-assisted analysis of musistudio/claude-code-router@99f24806c6 (2026-08-27). Data as JSON: /api/errors/03a1d2ddac5f1344. Report an issue: GitHub.