googleapis/mcp-toolbox · error

tokeninfo endpoint returned non-OK status %d: %s

Error message

tokeninfo endpoint returned non-OK status %d: %s

What it means

The tokeninfo endpoint replied with a non-200 status (body included in the message) — the ADC token was rejected, expired, or the request was otherwise refused by Google's OAuth infrastructure.

Source

Thrown at internal/sources/util.go:104

	client, err := google.DefaultClient(ctx,
		"https://www.googleapis.com/auth/userinfo.email")
	if err != nil {
		return "", fmt.Errorf("failed to call userinfo endpoint: %w", err)
	}

	// Retrieve the email associated with the token
	resp, err := client.Get("https://oauth2.googleapis.com/tokeninfo")
	if err != nil {
		return "", fmt.Errorf("failed to call tokeninfo endpoint: %w", err)
	}
	defer resp.Body.Close()

	bodyBytes, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("error reading response body %d: %s", resp.StatusCode, string(bodyBytes))
	}
	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("tokeninfo endpoint returned non-OK status %d: %s", resp.StatusCode, string(bodyBytes))
	}

	// Unmarshal response body and get `email`
	var responseJSON map[string]any
	err = json.Unmarshal(bodyBytes, &responseJSON)
	if err != nil {

		return "", fmt.Errorf("error parsing JSON: %v", err)
	}

	emailValue, ok := responseJSON["email"]
	if !ok {
		return "", fmt.Errorf("email not found in response: %v", err)
	}

	fullEmail, ok := emailValue.(string)
	if !ok {
		return "", fmt.Errorf("email field is not a string")

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Refresh Application Default Credentials
2. Check the response body in the error for the specific OAuth failure
3. Verify the credential has the userinfo.email scope

When it happens

Trigger: Thrown at internal/sources/util.go:104 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/24639b9b67ee3d9f. Report an issue: GitHub.