> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mzizi.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# The toolchain

> The tools built to support the Mzizi language: the mz compiler that implements it, the benchmark, the MCP server, the CLI and the skills bundle. The toolchain is not the language. Free to use, with no sign-in except for the Fundi tools.

**The toolchain is not the language.** Mzizi is a programming language: its syntax, type
system, semantics and contracts. The toolchain is built to support it: to implement it,
check it, measure it, and put what Mzizi knows in front of the agents that write it.

**The harness is the core of Mzizi, and the toolchain attaches to it natively.** The harness
is the layer an agent reads and works through: the language as an agent sees it (grammar,
types, contracts, canonical form), the agent protocol (`mz check --agent`, its diagnostics
and fixes; RFC-0001 §4), and the plugin host that `mz`, the CLI, the MCP server and plugins
attach to. Part of it exists today, in this toolchain, as `mz check --agent`'s output. The
harness as a whole is designed, not built, and the language is writing its RFC. It lives in
the language repository, `mzizi-dev/mzizi`, and the CLI, the MCP server and `fundi` are its
clients. It is not
the Phase 0 benchmark harness in `benchmarks/harness/`, which is the scorer listed below.

## What is in it

| Tool | What it is | Where it comes from | Cost |
| - | - | - | - |
| [`mz`, the compiler](/compiler) | `mz check --agent`, `mz fix`, `mz contract`, `mz outline`, `mz build` (a service only), `mz hash`, `mz ir` | `mzizi-dev/mzizi`, built from source | Free, open source |
| [The benchmark](/benchmark) | `mzbench`, the scorer, the Dioxus, Leptos, React and `mzizi-be` arms, the probe crate, the kill-criterion driver, the pilot results | `mzizi-dev/mzizi`, under `benchmarks/` | Free, open source |
| [The MCP server](/toolchain/mcp) | `mcp.mzizi.dev/mcp`: registry, tokens, doctrine, skills and the docs | `@nyuchi/mzizi-mcp` | Free, no sign-in |
| [The CLI](/toolchain/cli) | `mzizi add`, and `fundi explore`, `plan` and `chat` | `@nyuchi/mzizi-cli` | Free, no gate |
| [The skills](/toolchain/skills) | Five agent skills: the language, Mzizi Roots, the design system, backends and discoverability | `@nyuchi/mzizi-skills` | Free |
| [The API](/platform/api-gateway) | `api.mzizi.dev/v1`: the registry over plain HTTP | `mzizi-dev/mzizi-api-gateway` | Free, no sign-in |

`mz` implements the language, and the benchmark measures it against the best existing
language for each kind of task. The rest put the language, its components and its docs
within an agent's reach: the MCP server, the CLI, the skills and the API serve the
[components](/roots/overview) (the language's UI layer) and the doctrine an agent needs to
write for them.

## Free, until Fundi

The owner decided on 29 September 2026 that **the MCP server and the CLI are free, with no
gate.** Gating starts at **Fundi**, which ties into the console at `app.mzizi.dev`. The Fundi
tools (`mzizi_fundi`, and `mzizi_report_issue`, which files into the Fundi issue desk) need a
signed-in console user. Everything else is served without auth.

That is live: on 30 September 2026 an anonymous `tools/list` on `mcp.mzizi.dev/mcp` returned
all fourteen tools, and calling a Fundi tool without sign-in answered with how to sign in.
See [the MCP server](/toolchain/mcp).

## No database behind any of it

The compiler reads a file and writes to standard output. The benchmark writes results into
the repository. The MCP server and the API serve the registry's files, bundled at build
time from a pinned registry commit. None of them has a database. The only database in Mzizi
is the console's. See [where data lives](/platform/data).

## Where the source is

`mzizi-dev/mzizi` and `mzizi-dev/mzizi-api-gateway` are public. The MCP server, the CLI and
the skills bundle are built in a private tooling repository, `mzizi-dev/agent-tools`, so
these docs link their published npm packages rather than their source.


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