Give your AI
real LaTeX hands
letX runs a hosted MCP server at https://api.letx.app/mcp. Connect it to Claude, ChatGPT, or any MCP client and the assistant gets ten tools: search 1000+ LaTeX templates, create a project, read and edit its files, and compile it to a real PDF on letX’s TeX Live compile farm. Nothing to install, free on every account, and it signs in with OAuth so the client never sees your password.
Set it up in about two minutes
Every client points at the same URL. Pick yours for the exact clicks.
The ten tools, and what each one may do
Five of them cannot change anything you own. The other five do the work, and every write keeps the previous version in letX’s history.
| Tool | What it does | Access |
|---|---|---|
| search_templates | Search the 1000+ free template library: university theses, IEEE, ACM, Elsevier and Springer journal formats, CVs, posters, decks. | read only |
| get_template | Full details for one template: description, author, licence, preview, and its page on letx.app. | read only |
| list_projects | List the signed-in account's projects, so the assistant knows what exists before touching anything. | read only |
| list_project_files | List the documents and uploaded assets in a project, with exact paths. | read only |
| read_project_file | Read one document, such as main.tex, chapters/intro.tex or refs.bib. | read only |
| create_project_from_template | Start a new project from a template slug and hand back an editor link. | writes |
| create_project | Create a project from LaTeX files the assistant wrote (main.tex required). | writes |
| update_project_file | Create or replace a document. A version snapshot is saved first, so any edit can be undone from letX history. | writes |
| compile_latex | Compile loose LaTeX source to a PDF without choosing a project. Returns a download link, or the errors to fix. | writes |
| compile_project | Compile a project and return the PDF, or the compile log when it fails. | writes |
ChatGPT’s deep-research mode also sees search and fetch, the two names it looks for by convention. They map onto the same template library.
What it looks like in practice
“Start my thesis from my university’s template.”
search_templates finds the department format, create_project_from_template opens the project, and you get an editor link with the title page already filled in.
“This paper won’t build. Fix it.”
compile_project returns the real latexmk log, not a guess. The assistant reads the failing line, edits the file, and compiles again until the PDF comes out.
“Turn these results into a table and rebuild the PDF.”
read_project_file, update_project_file, compile_project. Three calls, one PDF, and the version before the edit is still in your history.
Questions
What is the letX MCP server?
letX runs a hosted Model Context Protocol server at https://api.letx.app/mcp. Connecting it gives an AI assistant ten tools: it can search 1000+ LaTeX templates, create letX projects, read and edit the files in them, and compile them to PDF on letX's TeX Live compile farm. There is nothing to install and nothing to run locally.
Which AI clients can connect to it?
Any MCP client that supports remote servers with OAuth. It is tested with Claude (Pro, Max, Team), ChatGPT (Plus, Pro, Team with developer mode), and Claude Code. Point any other MCP client at the same URL. The server implements the standard rather than a per-vendor integration.
Does it cost anything?
Connecting is free on every letX account, including free accounts. Compiles draw on the plan quota the account already has; free accounts get a daily allowance and Pro is unlimited.
What can the AI actually do to my account?
Only what the consent screen lists: browse templates, list and read your projects, write files into them, and compile. It cannot delete a project, change who a project is shared with, read your password, or see projects other people own. Every file it writes keeps the previous version in letX history, so an edit can be rolled back.
Do I have to give it my password?
No. The connection uses OAuth 2.1: the client opens letx.app, you sign in there and approve the scopes, and the client receives a token it can use. It never sees your credentials. Revoke it any time from Settings → Connected Accounts.
Can the assistant compile LaTeX without me opening letX?
Yes, that is what compile_latex is for. Give the assistant your source and it returns a PDF link. Images and figures are the exception: those need a real project, so create the project and upload them in the letX editor, then let the assistant edit and recompile it.
How is this different from an AI that just writes LaTeX in chat?
A chat assistant hands you code you still have to paste somewhere and compile. Over MCP the assistant compiles it, reads the actual error log, and fixes it. That is the same loop a person does by hand, without leaving the conversation. The output is a PDF you can open, not a snippet you hope builds.
Prefer to write in the editor? Lexi is the same capability built into letX itself, and the AI LaTeX editor comparison covers how the options differ.