googleapis/mcp-toolbox · error

unable to create connection client: %w

Error message

unable to create connection client: %w

What it means

initFalkorDBClient returns this when falkordb.FalkorDBNew(opts) fails to construct the connection client; Initialize then re-wraps it as 'unable to create client'. It covers errors raised while setting up the Redis-protocol client (options parsing, network setup).

Source

Thrown at internal/sources/falkordb/falkordb.go:129

	//nolint:all // Reassigned ctx
	ctx, span := sources.InitConnectionSpan(ctx, tracer, SourceType, r.Name)
	defer span.End()

	opts := &falkordb.ConnectionOption{
		Addr:     net.JoinHostPort(r.Host, r.Port),
		Username: r.Username,
		Password: r.Password,
	}
	if r.TLS.Enabled {
		opts.TLSConfig = &tls.Config{
			MinVersion:         tls.VersionTLS12,
			InsecureSkipVerify: r.TLS.InsecureSkipVerify,
		}
	}

	client, err := falkordb.FalkorDBNew(opts)
	if err != nil {
		return nil, fmt.Errorf("unable to create connection client: %w", err)
	}
	return client, nil
}

var _ sources.Source = &Source{}

type Source struct {
	Config
	Client *falkordb.FalkorDB
}

func (s *Source) IsReadOnly() bool {
	return false
}

func (s *Source) SourceType() string {
	return SourceType
}

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Check the wrapped %w error from FalkorDBNew for the precise cause
2. Validate host and port fields in tools.yaml (port as a numeric string)
3. Ensure the address is resolvable from the machine running the toolbox
4. Verify the falkordb-go v2 client version matches your deployment

// Go: validate options the way FalkorDBNew will consume them
addr := net.JoinHostPort(cfg.Host, cfg.Port)
if cfg.Host == "" {
    return fmt.Errorf("falkordb host is required")
}
if p, err := strconv.Atoi(cfg.Port); err != nil || p <= 0 || p > 65535 {
    return fmt.Errorf("falkordb port %q is not a valid port number", cfg.Port)
}

// Go: surface the wrapped cause
client, err := initFalkorDBClient(ctx, tracer, cfg)
if err != nil {
    slog.ErrorContext(ctx, "falkordb client construction failed", "cause", err)
    return err
}

When it happens

Trigger: Invalid ConnectionOption (malformed Addr from net.JoinHostPort, bad TLS config), or FalkorDBNew failing during dial/address resolution at construction time.

Common situations: Malformed host/port values in tools.yaml; IPv6 hosts combined with odd port strings; TLS options the client library rejects; internal falkordb-go version incompatibilities.

Related errors

• unable to create client: %w
• unable to connect successfully: %w
• unable to create db connection: %w
• sql.Open: %w
• failed to list relationship types: %w

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/75f6602bc2f06554. Report an issue: GitHub.