letX connector
Use letX inside Claude
Give Claude real LaTeX hands: compile to PDF, browse templates, and edit your letX projects from claude.ai.
Listed in Claude’s directory as a connector and as a plugin. Connecting needs a paid letX plan: Pro, Academic Pro, or a seat on a Team.
Pro is $18 a month, Academic Pro $9 a month for verified students, faculty and staff, and a Team seat $20 a month. See the plans
- 1
Open Connectors in Claude
In claude.ai or the Claude desktop app, go to Customize → Connectors and choose Discover, or press + in a chat, then Add connector → Browse connectors. On a Team or Enterprise plan an Owner adds letX for the organization first; a member who cannot add connectors sees Request instead, which asks the Owners.
- 2
Find letX
Search for LetX and open LetX LaTeX Editor, or go straight to its page in the directory. It carries the Community label, which means Anthropic screened it before listing it.
- 3
Press Connect to Claude
Claude reminds you that Community connectors have not been reviewed in depth, then opens the letX sign-in page: in the same tab on claude.ai, or in your browser from the desktop app.
- 4
Sign in, or make an account
If you are not already signed in to letX, this is where you land. Use Google or GitHub, or fill in the form. Already have an account? Press Sign in at the top. A free letX account can connect free for 7 days from the first time it connects, and the next screen says so; after that, connecting needs a paid letX plan (Pro, Academic Pro, or a seat on a Team).
- 5
Allow access
Last screen. Read what Claude is asking for, then press Allow access. letX never hands over your password, and you can disconnect later from Settings → Connected apps.
- 6
Turn it on in a chat
letX now shows under Your connectors as Connected. In a chat, press +, open Connectors and check letX is switched on. Then ask Claude to “compile this LaTeX”, “start my thesis from a university template”, or “read main.tex in my paper project and fix the references”.
Or add the letX plugin
The plugin is the same connector plus two skills, compile-and-fix and start-from-template, that teach Claude to compile, read the error by file and line, fix it and compile again. Plugins from the directory are on Claude’s Pro, Max, Team and Enterprise plans.
- 1
Open Plugins
In claude.ai or the Claude desktop app, go to Customize → Plugins and choose Discover, or open letX’s plugin page directly while signed in to Claude.
- 2
Add letX
Select letX, read what it contains, then press Add. It is saved to your account, so Cowork and Claude Code get it too.
- 3
Connect it
Adding a plugin connects nothing by itself. Open the plugin’s Connectors tab and connect letX, then sign in and allow access as in steps 4 and 5 above. If letX is connected already, the tab says Connected and you are done.
Adding it by URL instead
The same server also works as a custom connector, for example where an organization keeps its own list. These are the clicks.
- 1
Open the connector picker
In any Claude chat, click + next to the message box, then Add connector → Add custom connector. You can also start from Customize → Connectors.
1 the + button. 2 Add connector. 3 Add custom connector. - 2
Name it and paste the letX URL
Call it letX, put
https://api.letx.app/mcpin the address field, and press Continue.
1 the name shown in your connectors list. 2 the letX server address. 3 Continue. - 3
Keep the settings Claude detected
Leave Authentication on Always required and OAuth client on Use Anthropic’s hosted client metadata. Both are marked Detected because letX advertises them, so there is nothing to work out. Add no request headers, then press Add.
1 Always required. 2 Anthropic’s hosted client metadata. 3 Add. Leave request headers empty. - 4
Press Connect
Adding it does not sign you in. Claude shows the letX card with a Connect button, so press that.
Connect, on the letX card.
Then sign in and allow access exactly as in steps 4 and 5 above.
What Claude can do with letX connected
- Compile LaTeX → PDF on a real TeX Live farm
- Search 1000+ free LaTeX templates
- Start projects from any template
- Read & edit your project files
- See compile errors and fix them itself
- Hand off to the letX editor anytime
Frequently asked questions
Do I need a paid plan?
To keep it, yes. A free letX account can use Claude with letX for 7 days, no card needed, starting when you connect. After that, connecting Claude is part of letX’s paid plans (Pro, Academic Pro, or a seat on a Team), and the consent screen links to them. Compiles that Claude runs count against your letX plan like any other.
Is letX in Claude’s connectors directory?
Yes, listed as LetX LaTeX Editor at https://claude.ai/directory/letx. The directory listing and a custom connector added by URL reach the same server, https://api.letx.app/mcp, with the same thirteen tools.
Is there a letX plugin for Claude?
Yes. letX is in Claude’s directory as a plugin as well as a connector. The plugin adds two skills, compile-and-fix and start-from-template, to the same thirteen tools. Add it from Customize → Plugins in claude.ai or the desktop app and it follows your account into Cowork and Claude Code. In Claude Code you can also run claude plugin install letx@anthropic-plugin-directory.
Plugin or connector: which do I need?
Either one reaches the same server. The connector gives Claude the tools; the plugin adds the instructions for using them well, such as compiling again after each fix until the document builds. If you already connected letX, adding the plugin reuses that connection.
Which permissions does Claude get?
Only what you approve: template browsing, project read/write, and compiling. Every file edit keeps the previous version in letX’s history, and you can disconnect anytime from Settings → Connected apps.
Why does Claude show a warning before I connect?
letX is listed with the Community label, which means Anthropic screened it before listing it but has not reviewed it in depth, and Claude shows that reminder for every Community connector. A connector added by URL gets a similar warning, because Anthropic has not reviewed custom connectors at all. Either way it is a prompt to check who runs the server before you connect it.
Does this replace the letX editor?
No. It complements it. Claude is great for drafting and fixing; the letX editor adds live PDF preview, real-time collaboration, and SyncTeX navigation. Every project Claude touches links straight into the editor.