LetX engineering · August 29, 2026
LetX MCP: What an AI Client Can Actually Do
A tool-by-tool explanation of the LetX MCP server, its OAuth boundary, and how project editing differs from an ordinary chat attachment.
By Shihab Shahriar Antor · Updated 2026-08-29
The LetX MCP server gives a compatible AI client controlled access to templates, projects, text files, and LaTeX compilation. Its hosted endpoint is https://api.letx.app/mcp and authorization uses OAuth 2.1.
Why MCP is different from uploading a file
A chat attachment is a snapshot. If a model rewrites it, the result usually has to be copied back into the real project, and the model may never see the build result. An MCP connection exposes explicit project operations: list the project, inspect its files, read a selected text file, update source, and invoke compilation.
The result remains a LetX project that can be opened in the editor, reviewed visually, shared with collaborators, and recovered through version history.
The ten documented tools
The public guide lists tools for template search and detail lookup; project and file listing; file reading; creating a blank project or one based on a template; updating a project file; compiling supplied LaTeX; and compiling an existing project. LetX also documents conventional search and fetch compatibility for ChatGPT deep research.
The server is not a general remote shell. It exposes named operations for project text and compilation. Images and figures are still uploaded through the editor.
OAuth and consent
The external client should never receive a LetX password. OAuth redirects the user to LetX, presents the requested access, and returns a revocable authorization. Write access is materially different from read access and should be inspected before approval.
Connecting is free according to the published guide. Tool actions still use the account’s normal quotas and plan limits, so compilation is not unlimited on a Free account.
Example workflow
- Ask the client to search for an appropriate template or select an existing project.
- Read only the files needed for the task.
- Make a targeted update rather than replacing an entire repository.
- Compile and inspect the concrete result.
- Open the project in LetX for visual, citation, and collaborator review.
- Revoke the client when continued access is unnecessary.
See the complete LetX MCP research page for the current tool table and security boundaries.