googleapis/mcp-toolbox · error

error listing databases: %w

Error message

error listing databases: %w

What it means

Thrown in ListDatabase when the sqladmin Databases.List call (projects.instances.databases.list) fails. Listing databases for an instance returned an API error before the code could normalize resp.Items to an empty slice.

Source

Thrown at internal/sources/cloudsqladmin/cloud_sql_admin.go:249

		return nil, err
	}

	resp, err := service.Instances.Get(projectId, instanceId).Do()
	if err != nil {
		return nil, fmt.Errorf("error getting instance: %w", err)
	}
	return resp, nil
}

func (s *Source) ListDatabase(ctx context.Context, project, instance, accessToken string) (any, error) {
	service, err := s.GetService(ctx, accessToken)
	if err != nil {
		return nil, err
	}

	resp, err := service.Databases.List(project, instance).Do()
	if err != nil {
		return nil, fmt.Errorf("error listing databases: %w", err)
	}

	if resp.Items == nil {
		return []any{}, nil
	}

	type databaseInfo struct {
		Name      string `json:"name"`
		Charset   string `json:"charset"`
		Collation string `json:"collation"`
	}

	var databases []databaseInfo
	for _, item := range resp.Items {
		databases = append(databases, databaseInfo{
			Name:      item.Name,
			Charset:   item.Charset,
			Collation: item.Collation,

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Confirm the instance exists and is runnable (get_instance).
2. Fix the project ID and re-run.
3. Grant roles/cloudsql.viewer to the calling principal.
4. Retry on transient 5xx errors with backoff.
5. Inspect the wrapped googleapi.Error code for the exact failure reason.

Example fix

null

if instance == "" {
    return fmt.Errorf("instance is required to list databases")
}
// verify instance exists first
if _, err := src.GetInstance(ctx, project, instance, token); err != nil {
    return fmt.Errorf("cannot list databases; instance unavailable: %w", err)
}

func isRetryable(err error) bool {
    var gerr *googleapi.Error
    if errors.As(err, &gerr) {
        return gerr.Code == 429 || gerr.Code >= 500
    }
    return false
}

var out any
var err error
for attempt := 0; attempt < 3; attempt++ {
    out, err = src.ListDatabase(ctx, project, instance, token)
    if err == nil || !isRetryable(err) {
        break
    }
    time.Sleep(time.Duration(1<<attempt) * time.Second)
}
if err != nil {
    return fmt.Errorf("list databases failed after retries: %w", err)
}

When it happens

Trigger: Calling the list_databases tool against a non-existent instance, wrong project, or with a principal lacking cloudsql.databases.list permission.

Common situations: Instance deleted between tool selection and invocation; project ID mismatch; service account missing roles/cloudsql.viewer; transient 500/503 from the Cloud SQL API.

Related errors

• error listing instances: %w
• error cloning instance: %w
• error creating database: %w
• error creating user: %w
• error getting instance: %w

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/ea693d7e95a144f3. Report an issue: GitHub.