Jedit Pro includes a built-in MCP (Model Context Protocol) server that lets AI clients read and edit the documents you have open. This page explains how to use it from Claude Desktop.
MCP is an open specification authored by Anthropic, but as of May 2026, Claude Desktop and Claude Code are practically the only GUI clients that handle local MCP servers reliably. Cursor, Zed, Gemini CLI, and others support MCP to varying degrees, while the web versions of ChatGPT and Gemini cannot reach localhost and require HTTPS plus OAuth, so they currently cannot connect to a local MCP server.
This guide is therefore written around Claude Desktop. Support in other clients is changing rapidly and is not tracked here.
1. What you can do
- Let Claude read your open documents
- Let Claude edit them (replace / insert / create new)
- Run in-document searches via Claude (the Find Bar opens automatically)
- Work across multiple open documents
See the tools list below for the full set of operations.
2. Requirements
- macOS 15.6 or later
- Jedit Pro 1.0 or later
- Claude Desktop
- A Claude account (Free / Pro / Max)
No Node.js, npx, or other extra dependencies are needed; Jedit Pro ships with its own bridge executable.
3. Setup
3-1. Enable the MCP server in Jedit Pro
- Launch Jedit Pro.
- Menu:
Jedit Pro → Settings…(orCmd+,). - Select the AI / MCP pane from the toolbar.
- Check Enable MCP server.
- Verify that the status shows a green "Running on 127.0.0.1:NNNNN".
NNNNNis an auto-assigned port.- If you want a fixed port, type a number (e.g.
49200) into the Port field and toggle the checkbox off/on once.
3-2. Register with Claude Desktop
- In the same AI / MCP pane, click Install for Claude Desktop….
- A save dialog opens (it opens every time so you can confirm the location):
- Confirm the target folder is
~/Library/Application Support/Claude/. - Leave the file name as
claude_desktop_config.json. - Click Install.
- Confirm the target folder is
- If
claude_desktop_config.jsonalready exists, macOS shows its standard "A file with the same name already exists. Do you want to replace it?" sheet. Click Replace."Replace" here does not wipe out the existing file. Jedit Pro reads the current file first, adds or updates only the Jedit-Pro entry, and writes the merged result back. Your Claude Desktop settings and any other MCP servers (Filesystem, GitHub, etc.) are preserved.
The macOS save dialog always says "Replace" — the actual merge happens inside Jedit Pro. If you would like extra safety, back up
claude_desktop_config.jsonbefore clicking Install. - Wait for the "Installed for Claude Desktop" message.
- Quit Claude Desktop completely (
Cmd+Q) and relaunch it.
When the port or token changes later, press the same button to refresh the entry; the dialog pre-fills the folder you used last time.
3-3. Verify the connection
Open any document in Jedit Pro, start a new chat in Claude Desktop, and ask:
"What document is currently open in Jedit?"
If Claude calls list_open_documents and reports the title, the connection is working. The first time, Claude Desktop will pop up a "Allow Jedit-Pro to use these tools?" confirmation — accept it.
You do not need to see a "Jedit-Pro" label anywhere in Claude Desktop's window for this to work. Claude Desktop's UI changes frequently, and whether it displays available MCP server names near the message box varies by version (recent builds on macOS Tahoe often omit that label). The reliable test is whether Claude can actually call the tools.
4. Usage examples
Once connected, just ask Claude in plain language. It will call the right tools as needed.
| What you want | Example request to Claude |
|---|---|
| Read the whole document | "Read the active document and give me a summary." |
| Rewrite the entire document | "Rewrite this draft in a more formal tone, directly in the open tab." |
| Replace text | "Replace every occurrence of 'TODO' with 'DONE' in the current document." |
| Search | "Find the main function." (The Find Bar opens with matches highlighted.) |
| Create a new document | "Create a cleaned-up version of the meeting notes in a new tab." |
| Work across documents | "Read every open file and find any duplicate paragraphs across them." |
| Keep translation consistent | "Translate tab 1's English text into Japanese, matching the terminology already used in tab 2." |
"Find ..." example
The find_in_document tool not only returns matches as JSON but also opens the Find Bar in Jedit Pro and highlights every match. Jedit Pro is brought to the front, so you can see the result both in the Claude chat and in the editor.
If you want a silent search (no UI changes), ask Claude to "search without opening the Find Bar"; it will pass showInFindBar: false to the tool.
5. Available tools
| Tool | Function |
|---|---|
list_open_documents | id, title, file URL, and length of every open document |
get_active_document | Full text and current selection of the frontmost document |
get_document | Full text and current selection of a document by id |
replace_range | Replace a range with given text (undo-aware) |
insert_at | Insert text at a given location (undo-aware) |
find_in_document | Regex or literal search; results displayed in the Find Bar |
create_document | Create a new untitled document and optionally populate it |
6. Privacy and security
Reachability
- The MCP server binds to 127.0.0.1 (loopback) only.
- It cannot be reached from other machines or networks.
- No document content is ever sent over the Internet by Jedit Pro itself.
Authentication
- A 24-byte random Bearer token is required.
- Other user accounts on the same Mac cannot read it.
- You can rotate the token any time with the "Regenerate" button.
Communication with Claude (Anthropic)
- Claude Desktop sends only what you type in chat to Anthropic's servers.
- The results returned by MCP tools (i.e. document contents) are also sent so Claude can use them in its reply.
- To keep a sensitive document out of these calls, close it or disable the MCP server.
Availability
- The MCP server is active only while Jedit Pro is running.
- Quitting Jedit Pro immediately cuts off all access.
7. Troubleshooting
Jedit-Pro is not listed in Claude Desktop's tool menu
- Validate the JSON:
jq . ~/Library/Application\ Support/Claude/claude_desktop_config.json. - Quit Claude Desktop completely (Cmd+Q until the menu bar icon disappears) and relaunch it.
- Confirm that the AI / MCP pane status is green ("Running").
"Jedit Pro is not running" error
- Is Jedit Pro actually running?
- Is the MCP server enabled in its preferences?
- If you changed the port, press "Install for Claude Desktop" again to refresh the config.
Opening http://127.0.0.1:NNNNN/ in a browser shows "Not Found"
- This is expected. The server accepts only POST; GET returns 404 (or a small status page).
- That you got a response at all confirms the server is up.
The chosen port is in use
- Enter a different port (we recommend something in the 49152–65535 dynamic range).
- Or set it to
0to let the OS pick one.
Viewing server logs in Console.app
Launch /System/Applications/Utilities/Console.app, select your Mac in the sidebar, and type the following predicate into the search field in the top-right of the window (this is a Console filter, not a shell command — do not paste it into Terminal/bash):
subsystem:com.jedit.pro category:mcpThat filter narrows the log stream to MCP server entries. Click "Start" in the toolbar if you want to watch them live while you interact with Claude Desktop.