janhq/jan · error

Unexpected error while fetching models from

Error message

Unexpected error while fetching models from ${provider.provider}: ${error instanceof Error ? error.message : 'Unknown error'}

What it means

Generic fallback thrown when fetchModelsFromProvider catches an error that is neither a structured HTTP error nor a fetch/connectivity failure — e.g. response.json() throwing on invalid JSON, an unexpected TypeError, or a non-Error value thrown. The original message is embedded for diagnosis.

Solutions

1. Inspect the embedded inner message to identify the original failure.
2. curl the /models endpoint and check whether it returns valid JSON (not HTML).
3. Fix the proxy/server so a 200 response carries a JSON body.
4. Update the local server/provider config to a compatible API version.

Example fix

// before: proxy returns HTML 200 page for /models
// after: exclude /models from the catch-all proxy route
location /v1/ { proxy_pass http://backend; }

function looksLikeJsonResponse(ct: string | null): boolean {
  return !!ct && ct.includes('application/json')
}

try {
  await fetchModelsFromProvider(provider)
} catch (e) {
  if (e instanceof Error && e.message.startsWith('Unexpected error while fetching models')) {
    logInnerCause(e.message); suggestServerFix(provider.provider)
  }
}

When it happens

Trigger: response.json() fails because the endpoint returned HTML or invalid JSON; an unexpected runtime TypeError during parsing; a non-Error thrown from fetchTauri whose message lacks 'fetch'.

Common situations: Server returns an HTML error page or empty body with 200; a proxy intercepts the response; a bug in response parsing for a provider with an unusual schema; older server versions returning malformed payloads.

Understand the failure class

Background: JSON parse error: "Unexpected token" / "not valid JSON" / "failed to parse" — what JSON parsers are really complaining about — this error's family across 45 libraries.

Related errors

• Failed to parse update response
• ${error.message}
• error.message
• Failed to fetch model catalog
• Failed to fetch models from

AI-assisted analysis of janhq/jan@7205d770c1 (2026-09-17). Data as JSON: /api/errors/421c0e94ee780540. Report an issue: GitHub.

Appendix: source

Thrown at web-app/src/services/providers/tauri.ts:278

      if (
        error instanceof Error &&
        structuredErrorPrefixes.some((prefix) =>
          (error as Error).message.startsWith(prefix)
        )
      ) {
        throw new Error(error.message)
      }

      // Provide helpful error message for any connection errors
      if (error instanceof Error && error.message.includes('fetch')) {
        throw new Error(
          `Cannot connect to ${provider.provider} at ${provider.base_url}. Please check that the service is running and accessible.`
        )
      }

      // Generic fallback
      throw new Error(
        `Unexpected error while fetching models from ${provider.provider}: ${error instanceof Error ? error.message : 'Unknown error'}`
      )
    }
  }

  async updateSettings(
    providerName: string,
    settings: ProviderSetting[]
  ): Promise<void> {
    try {
      // API keys are persisted to the OS keyring only (via
      // register_provider_config), never to the extension's settings.json.
      // Blank the key entries at this single chokepoint regardless of caller.
      const isSecretKey = (key: string) =>
        key === 'api-key' || key === API_KEY_FALLBACKS_SETTING_KEY
      return ExtensionManager.getInstance()
        .getEngine(providerName)
        ?.updateSettings(

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