Sema: MCP server, setup and security

What Sema does

According to its repository: “MCP tools for Sema — eval, compile, build, format, and docs for a Lisp with LLM primitives.”

An MCP server gives an AI agent extra tools it calls during the conversation: the agent reads their description, decides to use them and gets the result back. Sema is listed under Code execution, a category of 32 servers in the directory, where it ranks #22 by stars.

Topics declared by the repository: interpreter, lisp, programming-language, rust, agentic-ai, agents.

Installing and connecting Sema

Distribution modes declared in the official MCP registry:

• MCPB bundle (one-click install in Claude Desktop)

Like any MCP server, you declare it in your client's configuration (Claude Desktop, Claude Code, Cursor, VS Code, Codex…): a name, the command that starts it or its URL, and any environment variables. The client then starts it and lists its tools. Project language: Rust.

Security: what to check

An MCP server runs code with the rights you give it, and the model reads its tool descriptions: a malicious or compromised server can hijack the agent. Read the code, or pick a maintained and widely used server, before connecting it.

Points found for Sema:

• System access: the Code execution category gives the agent control over files, a terminal, code or a browser. A booby-trapped instruction in content the agent reads (prompt injection) can then turn into an action.

Good practice: grant only the rights needed (least privilege), require human approval for irreversible actions, and run the AI agent security check.

Project activity and maintenance

Created on February 11, 2026, the sema-lisp/sema repository has 55 stars and 6 forks, with 5 open issues. It has more stars than 54% of the servers in the directory. It received changes this month. Version published in the registry: 1.37.0 (October 9, 2026).

Stars measure attention, not quality: a recent, heavily promoted project can collect them fast, while a useful but niche server will have few.