googleapis/mcp-toolbox · error

%g is an excluded value

Error message

%g is an excluded value

What it means

FloatParameter.Parse rejects a float because it appears in the parameter's excludedValues blacklist. This lets tool authors forbid specific known-bad decimal values (e.g. 0.0 as an invalid factor) while allowing all others. The value is a valid float; it is simply forbidden by config.

Source

Thrown at internal/util/parameters/parameters.go:929

	switch newV := v.(type) {
	default:
		return nil, &ParseTypeError{p.Name, p.Type, v}
	case float32:
		out = float64(newV)
	case float64:
		out = newV
	case json.Number:
		newI, err := newV.Float64()
		if err != nil {
			return nil, &ParseTypeError{p.Name, p.Type, v}
		}
		out = float64(newI)
	}
	if !p.IsAllowedValues(out) {
		return nil, fmt.Errorf("%g is not an allowed value", out)
	}
	if p.IsExcludedValues(out) {
		return nil, fmt.Errorf("%g is an excluded value", out)
	}
	if p.MinValue != nil && out < *p.MinValue {
		return nil, fmt.Errorf("%g is under the minimum value", out)
	}
	if p.MaxValue != nil && out > *p.MaxValue {
		return nil, fmt.Errorf("%g is above the maximum value", out)
	}
	return out, nil
}

func (p *FloatParameter) GetAuthServices() []ParamAuthService {
	return p.AuthServices
}

func (p *FloatParameter) GetDefault() any {
	if p.Default == nil {
		return nil
	}

View on GitHub (pinned to 8cc6e09de2)

Solutions

1. Resend with a float not in the excludedValues list (check the tool's parameter schema)
2. If 0.0 meant 'use default', omit the parameter so the configured default applies
3. If the value is legitimate, remove it from excludedValues in tools.yaml (or WithFloatExcludedValues) and redeploy

Example fix

// before
params := map[string]any{"factor": 0.0} // excludedValues include 0.0
// after
params := map[string]any{"factor": 1.0}

excluded := []float64{0.0}
func validateNotExcludedFloat(v float64, excluded []float64) error {
    for _, e := range excluded {
        if v == e { return fmt.Errorf("%g is excluded", v) }
    }
    return nil
}

func isExcludedFloat(v float64, excluded []float64) bool {
    for _, e := range excluded { if v == e { return true } }
    return false
}

out, err := tool.Parse(params)
if err != nil && strings.Contains(err.Error(), "is an excluded value") {
    // substitute a safe value or omit the param to use the default
}

When it happens

Trigger: Invoking a tool with a float that matches an entry in the FloatParameter's excludedValues (yaml 'excludedValues:' or WithFloatExcludedValues). Example: excludedValues [0.0] and the request passes 0.0.

Common situations: Blocking zero/negative multipliers that would break SQL; excluding NaN-like sentinels; defaults or templates still emitting a value that was later blacklisted.

Related errors

• %g is not an allowed value
• unable to process parameters: %w
• %d is not an allowed value
• %d is an excluded value
• %d is under the minimum value

AI-assisted analysis of googleapis/mcp-toolbox@8cc6e09de2 (2026-09-05). Data as JSON: /api/errors/1ab4b3909695bd82. Report an issue: GitHub.