prototype mcp server for using J from LLMs

[Michal Wallace]

MCP is the Model Context Protocol, a JSON-based protocol that lets LLMs like Claude
and ChatGPT / codex call outside tools.

Here is one for talking to J:

https://github.com/tangentstorm/j-mcp

It's basically a custom J front-end that talks to an external libj and wraps the normal REPL in the MCP protocol.

In theory, if you have claude, you should be able to download the .dxt and/or the .mcpb file, drop it onto
the "extensions" page in claude desktop, and tell it where your JHOME is, and then claude should (might?)
be able to create a J session and do stuff for you.

Let me know if you try it. Bug reports / feature requests welcome.

-michal (@tangentstorm)

[LdBeth]

>>>>> In <CAE6HCjkHT_RTghfjvR_fqmY0...@mail.gmail.com>

Thanks!
It works great on my side.
I'll use this to defeat the problem that Opus 4.7 cannot get 9.9-9.11 right. :D

[LdBeth]

After used this for a while, I think some tweaks to the prompt need to
be made to remind the LLM create a session before try to eval any
expressions.

And what about creating multi-line functions?