Check workspace and path resolution
Relative paths are resolved from a tool's working directory, which may not be the folder currently open in an editor. Compare the path against the workspace root and use an absolute path when the tool supports it and ambiguity matters.
Check for case differences, hidden extensions, Unicode characters, and renamed files. A visually similar character or a file named report.txt.txt can be hard to notice but still produce a not-found response.
Locate the intended file safely
Search within the intended workspace using a distinctive filename or a small, known directory. Confirm the returned path and contents so you do not edit a similarly named file in another project.
If the file is outside the tool's permitted scope, move or copy it only through an approved workflow. Do not broaden access or recursively inspect unrelated folders just to make the error disappear.