micro/go-micro · error

name is required

Error message

name is required

What it means

The built-in "get_service" MCP tool handler requires the caller to supply the "name" input parameter identifying which registered service to look up. When the parameter is absent or an empty string, the handler returns "name is required" as the tool error.

Source

Thrown at gateway/mcp/mcp.go:460

				names = append(names, svc.Name)
			}
			return map[string]interface{}{"services": names}, nil
		},
	})

	addFramework(&Tool{
		Name:        "micro_registry_get",
		Description: "Get details for a registered service including nodes and endpoints",
		InputSchema: map[string]interface{}{
			"type": "object",
			"properties": map[string]interface{}{
				"name": map[string]interface{}{"type": "string", "description": "Service name"},
			},
		},
		Handler: func(input map[string]interface{}) (interface{}, error) {
			name, _ := input["name"].(string)
			if name == "" {
				return nil, fmt.Errorf("name is required")
			}
			services, err := s.opts.Registry.GetService(name)
			if err != nil {
				return nil, err
			}
			return services, nil
		},
	})

	addFramework(&Tool{
		Name:        "micro_store_list",
		Description: "List keys in the data store",
		InputSchema: map[string]interface{}{"type": "object", "properties": map[string]interface{}{}},
		Handler: func(input map[string]interface{}) (interface{}, error) {
			keys, err := store.List()
			if err != nil {
				return nil, err
			}

View on GitHub (pinned to 24529f1404)

Solutions

1. Include a non-empty "name" string in the tool input: {"name": "myservice"}.
2. Check the service name against what the registry reports (ListServices) — names are case-sensitive.
3. On the client side, validate required params before sending the tools/call request.

Example fix

// before
{"method": "tools/call", "params": {"name": "get_service", "arguments": {}}}
// after
{"method": "tools/call", "params": {"name": "get_service", "arguments": {"name": "myservice"}}}

name, _ := input["name"].(string)
if name == "" {
    return errors.New("get_service requires a non-empty 'name' argument")
}

func validName(input map[string]interface{}) (string, bool) {
    n, ok := input["name"].(string)
    return n, ok && n != ""
}

result, err := callTool("get_service", map[string]interface{}{"name": svc})
if err != nil {
    if strings.Contains(err.Error(), "name is required") {
        // fix arguments and retry once
    }
}

When it happens

Trigger: An MCP client calls the get_service tool with input {} or input {"name": ""} — the empty name fails the guard before Registry.GetService is invoked.

Common situations: An LLM omits the required argument in its tool call; a hand-written JSON-RPC client forgets the params.name field; schema/tools listing was cached and the client sends outdated arguments.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• key is required
• topic is required
• ai model is nil
• ErrMissingTopic
• ap2: mandate id is required

AI-assisted analysis of micro/go-micro@24529f1404 (2026-09-01). Data as JSON: /api/errors/c5466243a6d942e9. Report an issue: GitHub.