Mort is a statically typed systems language that compiles to C. It's the language MORT OS is written in. No model has Mort in its training data, so an agent asked to write it will guess Rust-like syntax and get it wrong.

mort-mcp gives the agent what a human newcomer would use: a fast type checker with precise errors, a way to run programs, the language spec to search, and the exact signatures of the standard library.

> mort_check
FAILED:
error: <source>:4:1: argument 1 of 'strings.starts_with' expects []const u8, got *u8
        if strings.starts_with("mortos", "mort") {

> mort_std strings
// First byte offset of `needle` in `text`, or None if it does not occur.
pub fn index_of(text: []const u8, needle: []const u8) -> Option<u64>;
...

> mort_run
[exit 0]
1

Install

You need the Mort compiler. The simplest setup is a checkout, which also brings the docs and examples:

git clone https://github.com/0xmortuex/Mort
pip install mort-mcp ziglang     # ziglang = zero-install C backend for mort_run
claude mcp add mort --env MORT_HOME=/path/to/Mort -- mort-mcp

Without MORT_HOME, mort-mcp uses a mortc on your PATH (pip install git+https://github.com/0xmortuex/Mort). Checking, running and std lookup all work that way. mort_docs and mort_examples need the checkout.

Tools

Tool	What it does
`mort_check`	Type-check `source` text or `files` without building. Fast, and needs no C compiler. Returns diagnostics as `file:line:col` with the source line.
`mort_run`	Compile and run, with `stdin`, `args` and a timeout. Reports output and exit code.
`mort_emit_c`	Show the generated C. `freestanding=True` shows the kernel-mode output.
`mort_format`	Format with the official formatter (`mortc fmt`).
`mort_std`	List std modules, or show one module's public API: exact signatures, struct fields and doc comments.
`mort_docs`	Search the language specification and reference docs, e.g. "resource struct cleanup" or "integer overflow".
`mort_examples`	List or read the compiler's example programs.
`mort_version`	Compiler and language version, and where the compiler was found.

Every tool calls mortc through its command-line interface, and reads std signatures and docs from the installed compiler. Answers therefore match the version you're running, even as the language changes.

Tests

pip install ".[test]" "ruff==0.16.0" "mypy==2.3.0" ziglang
ruff check src tests && mypy --strict src
MORT_HOME=/path/to/Mort pytest tests

Without MORT_HOME, only the unit tests and the MCP handshake test run. CI checks out the latest Mort and also runs every night, so a change to the compiler's CLI or docs layout shows up as a failing build.