What causes "description is required for tool %q" in googleapis/mcp-toolbox?

Add a non-empty `description:` field to the tidb-execute-sql tool.

description is required for tool %q

Error message

description is required for tool %q

What it means

tidb-execute-sql requires a `description` in the tool config; Initialize rejects empty descriptions before constructing the tool. The description is required because it is included in the tool manifest shown to the LLM client.

Source

Thrown at internal/tools/tidb/tidbexecutesql/tidbexecutesql.go:67

}

type Config struct {
	tools.ConfigBase `yaml:",inline"`
	Type             string                 `yaml:"type" validate:"required"`
	Source           string                 `yaml:"source" validate:"required"`
	Annotations      *tools.ToolAnnotations `yaml:"annotations,omitempty"`
}

// validate interface
var _ tools.ToolConfig = Config{}

func (cfg Config) ToolConfigType() string {
	return resourceType
}

func (cfg Config) Initialize(context.Context) (tools.Tool, error) {
	if cfg.Description == "" {
		return nil, fmt.Errorf("description is required for tool %q", cfg.Name)
	}

	sqlParameter := parameters.NewStringParameter("sql", "The sql to execute.")
	allParameters := parameters.Parameters{sqlParameter}

	return Tool{
		BaseTool: tools.NewBaseTool(
			cfg,
			tools.GetAnnotationsOrDefault(cfg.Annotations, tools.NewDestructiveAnnotations),
			tools.Manifest{Description: cfg.Description, Parameters: allParameters.Manifest(), AuthRequired: cfg.AuthRequired},
			allParameters,
		),
	}, nil
}

// validate interface
var _ tools.Tool = Tool{}

View on GitHub (pinned to 8cc6e09de2)

Solutions

Add a non-empty `description:` field to the tidb-execute-sql tool.
Confirm indentation places description within the tool config.
Ensure any templated description evaluates to non-empty text.

Example fix

# before
kind: tidb-execute-sql
source: my-tidb
# after
kind: tidb-execute-sql
source: my-tidb
description: "Run arbitrary SQL against TiDB."

Defensive patterns

Strategy: validation

Validate before calling

yq '.tools[] | select(.kind == "tidb-execute-sql") | select(.description == null or .description == "") | .name' tools.yaml

Type guard

func validTidbTool(c tidbexecutesql.Config) error {
    if c.Description == "" { return errors.New("description is required") }
    return nil
}

Try / catch

tool, err := cfg.Initialize(ctx)
if err != nil {
    log.Fatalf("tidb tool config error: %v", err)
}

Prevention

Include description in every tool definition from the start.
CI-lint configs for mandatory fields.
Double-check YAML indentation when a seemingly-present field is not read.

When it happens

Trigger: A `tidb-execute-sql` tool entry without `description:` or with description: ""; templated description resolving empty.

Common situations: Writing configs by hand and skipping description; YAML anchor/indent mistakes; bulk-generated configs missing the field.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/27b80f85c6716efd. Report an issue: GitHub.