Select, preview, confirm turns an edit into something the model has to look at before committing, and the content id means a stale selection fails instead of overwriting the wrong lines. The 50-line default ceiling pushes edits to stay small rather than becoming whole-file rewrites. Two things to decide before connecting it: `PROTECTED_PATHS`, because a file editor reaches whatever you do not exclude, and whether `run_tests` should be available at all, since running a project's tests means running its code.
A FastMCP file editor built around a deliberate workflow: set a file, read it, select a line range, propose replacement lines, review the diff, then commit or discard. Selections carry a SHA-256 content id so an edit cannot land on text that changed underneath it, and Python and JavaScript/JSX files are syntax-checked before the write.
- A working file set by absolute path, and a new file created with its parent directories and its first line pre-selected — `set_file`, `new_file`
- The whole file read with line numbers, or a specific line range, so edits are addressed by number rather than by guessing at matching text — `skim`, `read`
- Text located by exact match, and a function or method located by name — Python via the AST and tokenize modules including decorators and docstrings, JavaScript and JSX via Babel with a regex fallback — `find_line`, `find_function`
- The edit itself as four separate steps: select a range, propose new lines and get a git-style diff preview back, then apply or discard — `select`, `overwrite`, `confirm`, `cancel`
- Directory contents listed, and the current file deleted — `listdir`, `delete_file`
- Python tests run with pytest and the interpreter path configured for module resolution — `run_tests`, `set_python_path`
No account and no key — it works on your local filesystem. The package is `text-editor` (0.1.0 in pyproject) and installs the `editor-mcp` command; Python 3.7+. JavaScript and JSX syntax checking additionally wants Node.js with `@babel/core`, `@babel/cli`, `@babel/preset-env` and `@babel/preset-react`, and can be switched off with `ENABLE_JS_SYNTAX_CHECK`. `MAX_SELECT_LINES` raises the per-edit ceiling from its default of 50, and `FAIL_ON_PYTHON_SYNTAX_ERROR` and `FAIL_ON_JS_SYNTAX_ERROR` decide whether a syntax error cancels the write. Set `PROTECTED_PATHS` before you connect it: it takes a comma-separated list of paths and glob patterns that are denied outright, which is what keeps `.env` files, key material and anything matching `*secret*` out of reach.
One command — pip install git+https://github.com/danielpodrazka/mcp-text-editor.git