Tencent/WeKnora · error

old_string is required; copy the exact text to change, inclu

Error message

old_string is required; copy the exact text to change, including whitespace

What it means

applySandboxEdit precondition guard: old_string is empty, so there is no text to locate and replace; the edit helper refuses to run because an empty search string would match everywhere and corrupt the file.

Source

Thrown at internal/agent/tools/sandbox_edit.go:278

			"path":         clean,
			"root":         rootDir,
			"name":         path.Base(clean),
			"size":         len(content),
			"replacements": replacements,
		},
	}, nil
}

// Cleanup releases any resources.
func (t *EditSandboxFileTool) Cleanup(ctx context.Context) error {
	return nil
}

// applySandboxEdit performs an exact string replacement. replaceAll=false
// requires a unique match.
func applySandboxEdit(content, oldString, newString string, replaceAll bool) (string, int, error) {
	if oldString == "" {
		return "", 0, fmt.Errorf("old_string is required; copy the exact text to change, including whitespace")
	}
	if oldString == newString {
		return "", 0, fmt.Errorf("old_string and new_string are identical; no change would be made")
	}
	n := strings.Count(content, oldString)
	if n == 0 {
		return "", 0, fmt.Errorf("old_string was not found in the file. Copy the exact text (including whitespace) from the file")
	}
	if n > 1 && !replaceAll {
		return "", 0, fmt.Errorf(
			"old_string matched %d times. Include more surrounding context so it is unique, or set replace_all=true",
			n,
		)
	}
	if replaceAll {
		return strings.ReplaceAll(content, oldString, newString), n, nil
	}
	return strings.Replace(content, oldString, newString, 1), 1, nil

View on GitHub (pinned to 988cbb0330)

Solutions

1. Copy the exact target text (including whitespace) into old_string
2. Validate old_string is non-empty before invoking the edit tool
3. For whole-content rewrites use a write tool instead of an edit

When it happens

Trigger: Thrown at internal/agent/tools/sandbox_edit.go:278 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Tencent/WeKnora@988cbb0330 (2026-09-02). Data as JSON: /api/errors/213fa900bbe8bf31. Report an issue: GitHub.