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LABSCO SUMMARY
The extra steps are the feature.
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.
What it is
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.
What you get
- 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
Requirements
No account and no key — it works on your local filesystem. The package is text-editor (version 0.1.0) and installs the text-editor command; it needs Python 3.11 or later. 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.
Setup effort
One command — pip install git+https://github.com/danielpodrazka/mcp-text-editor.git
USE CASES
01
Changing one function without touching the rest of the file
Locate the function by name to get its exact line range, select those lines, propose the replacement, and read the diff before committing.
02
Editing code you have not read
Skim the file with line numbers to get the shape of it, then read only the region you intend to change.
03
Backing out of a bad edit before it lands
Look at the diff preview, discard it, and keep the selection so the next attempt starts from the same lines.
04
Keeping broken Python out of the file
Leave the syntax check on so a proposed edit that would not parse cancels itself and leaves the lines selected for another try.
05
Checking a change actually works
Run the project's pytest suite from the same session, with the Python path set so imports resolve.
06
Writing a config file you do not want reopened
Create a file matching a protected pattern and populate it in one pass — once you move to another file, the protection prevents it being read back.
14 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
confirm
Confirm action
delete_file
Delete current file
find_function
Find a function or method definition in a Python or JS/JSX file. Uses AST parsers.
find_line
Find lines that match provided text in the current file.
listdir
new_file
Creates a new file.
After creating new file, the first line is automatically selected for editing. Automatically creates parent directories if they don't exist.
overwrite
Overwrite the selected lines with new text. Amount of new lines can differ from the original selection
read
Read lines from the current file from start line to end line, returning them in a dictionary like {"lines":[[1,"text on first line"],[2,"text on second line"]]}. This makes it easier to find the precise lines to select for editing.
run_tests
Run pytest tests using the specified Python virtual environment.
select
Select lines from for subsequent overwrite operation.
set_file
Set the current file to work with.
This is always the first step in the workflow. You must set a file before you can use other tools like read, select etc.
set_python_path
Set it before running tests so the project is correctly recognized
skim
Read text from the current file, truncated to the first SKIM_MAX_LINES lines.
Returns: dict: lines, total_lines, max_select_lines
BEFORE YOU INSTALL
What to know first
Tools you get
14 tools when we connected.
Requires
Python 3.11+
Where it runs
The documented client runs the server on your machine.
CONTEXT COST
Light Standing cost
Rated by the size of the 14 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Server setup
TERMINAL
pip install git+https://github.com/danielpodrazka/mcp-text-editor.gitMCP Clients
Claude Desktop
CLAUDE DESKTOP · JSON
{
"mcpServers": {
"text-editor": {
"command": "text-editor",
"env": {
"MAX_SELECT_LINES": "100",
"ENABLE_JS_SYNTAX_CHECK": "0",
"FAIL_ON_PYTHON_SYNTAX_ERROR": "1",
"FAIL_ON_JS_SYNTAX_ERROR": "0",
"PROTECTED_PATHS": "*.env,.env*,config*.json,*secret*,/etc/passwd,/home/<YOUR_USERNAME>/.ssh/id_rsa"
}
}
}
}
