What causes "path is required and cannot be empty" in vxcontrol/pentagi?

Provide a valid absolute path inside the container (e.g. /home/user/report.txt)

path is required and cannot be empty

Error message

path is required and cannot be empty

What it means

ReadFile validates its input before doing any container work: an empty path cannot name a file inside the container, so the call is rejected immediately with this error. It is a guard against building a meaningless 'cat ''' command.

Source

Thrown at backend/pkg/tools/terminal.go:331

	results := dst.String()
	// Style system output with color coding
	styledOutput := fmt.Sprintf("%s%s%s%s", ansiColorSystemMsg, results, ansiColorReset, ansiLineTerminator)
	_, err = t.tlp.PutMsg(ctx, database.TermlogTypeStdout, styledOutput, t.containerID, t.taskID, t.subtaskID)
	if err != nil {
		return "", fmt.Errorf("failed to put terminal log (stdout): %w", err)
	}

	if results == "" {
		results = "Command completed successfully with exit code 0. No output produced (silent success)"
	}

	return results, nil
}

func (t *terminal) ReadFile(ctx context.Context, flowID int64, path string) (string, error) {
	if path == "" {
		return "", fmt.Errorf("path is required and cannot be empty")
	}

	cwd := docker.WorkFolderPathInContainer
	escapedPath := strings.ReplaceAll(path, "'", "'\"'\"'")
	catCommand := fmt.Sprintf("cat '%s'", escapedPath)
	// Format read file command with styling
	styledCommand := fmt.Sprintf("%s $ %s%s%s%s", cwd, ansiColorInputCmd, catCommand, ansiColorReset, ansiLineTerminator)
	_, err := t.tlp.PutMsg(ctx, database.TermlogTypeStdin, styledCommand, t.containerID, t.taskID, t.subtaskID)
	if err != nil {
		return "", fmt.Errorf("failed to put terminal log (read file cmd): %w", err)
	}

	content, err := t.readFileFromContainer(ctx, flowID, path)
	if err != nil {
		return "", err
	}

	// Style file content output

View on GitHub (pinned to ea665308ba)

Solutions

Provide a valid absolute path inside the container (e.g. /home/user/report.txt)
Validate/trim the path at the call site before invoking ReadFile
If path comes from tool arguments, enforce non-empty in the tool's input schema/validation

Example fix

// before
content, err := term.ReadFile(ctx, flowID, path) // path == ""
// after
path = strings.TrimSpace(path)
if path == "" {
    return errors.New("cannot read file: path is empty")
}
content, err := term.ReadFile(ctx, flowID, path)

Defensive patterns

Strategy: validation

Validate before calling

func safeReadFile(ctx context.Context, term Terminal, flowID int64, path string) (string, error) {
    path = strings.TrimSpace(path)
    if path == "" {
        return "", errors.New("path is required")
    }
    return term.ReadFile(ctx, flowID, path)
}

Type guard

func validPath(path string) bool {
    return strings.TrimSpace(path) != ""
}

Try / catch

content, err := term.ReadFile(ctx, flowID, path)
if err != nil && strings.Contains(err.Error(), "path is required") {
    return fmt.Errorf("read skipped: %w", err)
}

Prevention

Validate tool-call arguments at the schema layer (non-empty path)
Trim whitespace before calling ReadFile
Default optional path fields explicitly
Never pass through raw LLM-generated arguments unchecked

When it happens

Trigger: Calling terminal.ReadFile(ctx, flowID, "") — e.g. the caller's path variable was never populated, an upstream tool returned an empty string, or an optional path field was not defaulted.

Common situations: LLM agent invokes the read-file tool with a missing/blank path argument; config or task data lacking a file field; string trimming reducing a value to "".

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

AI-assisted analysis of vxcontrol/pentagi@ea665308ba (2026-09-01). Data as JSON: /api/errors/a53890ea9fcc9069. Report an issue: GitHub.