wavetermdev/waveterm · error

input is required

Error message

input is required

What it means

parseReadTextFileInput rejects a nil input before attempting to unmarshal the read_text_file parameters. The tool's input argument must be a JSON-like object; nothing to read means no filename can be extracted, so it fails fast with this error.

Source

Thrown at pkg/aiusechat/tools_readfile.go:36

)

const ReadFileDefaultLineCount = 100
const ReadFileDefaultMaxBytes = 50 * 1024
const StopReasonMaxBytes = "max_bytes"

type readTextFileParams struct {
	Filename string  `json:"filename"`
	Origin   *string `json:"origin"` // "start" or "end", defaults to "start"
	Offset   *int    `json:"offset"` // lines to skip, defaults to 0
	Count    *int    `json:"count"`  // number of lines to read, defaults to DefaultLineCount
	MaxBytes *int    `json:"max_bytes"`
}

func parseReadTextFileInput(input any) (*readTextFileParams, error) {
	result := &readTextFileParams{}

	if input == nil {
		return nil, fmt.Errorf("input is required")
	}

	if err := utilfn.ReUnmarshal(result, input); err != nil {
		return nil, fmt.Errorf("invalid input format: %w", err)
	}

	if result.Filename == "" {
		return nil, fmt.Errorf("missing filename parameter")
	}

	if result.Origin == nil {
		origin := "start"
		result.Origin = &origin
	}

	if *result.Origin != "start" && *result.Origin != "end" {
		return nil, fmt.Errorf("invalid origin value '%s': must be 'start' or 'end'", *result.Origin)
	}

View on GitHub (pinned to a4447c1563)

Solutions

1. Provide a non-null input object: {"filename": "/path/to/file"}.
2. If building tool calls programmatically, serialize parameters instead of passing nil.
3. Wrap the tool call in validation that asserts input is an object before sending.

Example fix

// before
readTextFileCallback(nil)
// after
readTextFileCallback(map[string]any{"filename": "/tmp/log.txt"})

if input == nil || len(input.(map[string]any)) == 0 { return errors.New("input object required") }

func isNonEmptyObject(v any) bool {
    m, ok := v.(map[string]any)
    return ok && len(m) > 0
}

params, err := parseReadTextFileInput(input)
if err != nil && err.Error() == "input is required" {
    // return usage help: requires {filename: string}
}

When it happens

Trigger: Invoking read_text_file with input=null / omitted argument, or the MCP tool-call layer delivering an empty params map.

Common situations: Hand-written tool-call JSON missing the "input" wrapper; agent frameworks dropping empty object arguments; tests calling the callback with nil.

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

• invalid input format: %w
• missing filename parameter
• invalid origin value '%s': must be 'start' or 'end'
• offset must be non-negative, got %d
• count must be at least 1, got %d

AI-assisted analysis of wavetermdev/waveterm@a4447c1563 (2026-09-01). Data as JSON: /api/errors/8839e4764563c0ef. Report an issue: GitHub.