The toolchain

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 language harness is the spine of the language, and the toolchain is meant to attach to it. It is the layer an agent reads and works through: every feature registered once, as an entry inside the compiler (mz harness definition), the agent protocol (mz check --agent, its diagnostics and fixes; RFC-0001 §4), and a plugin host that mz, the CLI, the MCP server and plugins are to attach to. A first slice exists: mz dispatches on its command table, and mz harness serves the entries. The plugin host is design only (RFC-0012, a draft). 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. See the language harness.

What is in it

Tool	What it is	Where it comes from	Cost
`mz`, the compiler	`mz check --agent`, `mz fix`, `mz contract`, `mz outline`, `mz build`, `mz run`, `mz harness`, `mz hash`, `mz ir`	`mzizi-dev/mzizi`, built from source	Free, open source
The 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	`mcp.mzizi.dev/mcp`: registry, tokens, doctrine, skills and the docs	`@nyuchi/mzizi-mcp`	Free, no sign-in
The CLI	`mzizi add`, and `fundi explore`, `plan` and `chat`	`@nyuchi/mzizi-cli`	Free, no gate
The skills	Seven agent skills: the language, Mzizi Roots, the design system, backends, discoverability, and the two `dev` skills every agent loads	`@nyuchi/mzizi-skills`	Free
The API	`api.mzizi.dev/v1`: the registry over plain HTTP	`mzizi-dev/mzizi-api` (formerly `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 (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 7 October 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.

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.

Where the source is

mzizi-dev/mzizi and mzizi-dev/mzizi-api (formerly 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.