wavetermdev/waveterm · error

values must be an array

Error message

values must be an array

What it means

The "values" key exists but its value is not a JSON array ([]any). The callback type-asserts valuesInterface.([]any) and returns this error on failure. Note an empty array is explicitly allowed (returns sum 0), so this error is strictly about the wrong type, not emptiness.

Source

Thrown at pkg/aiusechat/tools.go:299

				},
			},
			"required":             []string{"values"},
			"additionalProperties": false,
		},
		ToolAnyCallback: func(input any, toolUseData *uctypes.UIMessageDataToolUse) (any, error) {
			inputMap, ok := input.(map[string]any)
			if !ok {
				return nil, fmt.Errorf("invalid input format")
			}

			valuesInterface, ok := inputMap["values"]
			if !ok {
				return nil, fmt.Errorf("missing values parameter")
			}

			valuesSlice, ok := valuesInterface.([]any)
			if !ok {
				return nil, fmt.Errorf("values must be an array")
			}

			if len(valuesSlice) == 0 {
				return 0, nil
			}

			sum := 0
			for i, val := range valuesSlice {
				floatVal, ok := val.(float64)
				if !ok {
					return nil, fmt.Errorf("value at index %d is not a number", i)
				}
				sum += int(floatVal)
			}

			return sum, nil
		},
	}

View on GitHub (pinned to a4447c1563)

Solutions

1. Pass values as a JSON array: {"values": [1, 2, 3]} — not a string, number, or object
2. If the model keeps sending strings, strengthen the tool description with an explicit example showing an array literal
3. Validate client-side before invoking: check Array.isArray(values) / reflect.Kind Slice before calling the tool

Example fix

// before
anySum({"values": "1,2,3"})
// after
anySum({"values": [1, 2, 3]})

raw, ok := m["values"]; if !ok { return errors.New("values required") }; if _, ok := raw.([]any); !ok { return errors.New("values must be a JSON array") }

func isAnySlice(v any) ([]any, bool) { s, ok := v.([]any); return s, ok }

out, err := tool.Call(input); if err != nil && strings.Contains(err.Error(), "values must be an array") { return fmt.Errorf("bad tool args: %w", err) }

When it happens

Trigger: Tool called with values as a non-array: e.g. {"values": 5}, {"values": "1,2,3"}, {"values": {"0":1}}, or null.

Common situations: Model passing a comma-separated string instead of an array; passing a single number instead of a one-element array; passing an object keyed by indices; client SDK serializing variadic args as scalars.

Related errors

• value at index %d is not a number
• invalid input format
• invalid input format: %w
• Invalid path part: ${pathPart}
• convertFileUIMessagePart expects 'file' type, got '%s'

AI-assisted analysis of wavetermdev/waveterm@a4447c1563 (2026-09-01). Data as JSON: /api/errors/e4297eb398e9dcdd. Report an issue: GitHub.