Riot is a tech-demo of a stack and tooling for building applications in OCaml.
It is heavily opinionated, and designed from the ground up to get
out of your way and help you ship great software with agents.
It comes with a single tool for all your needs, a modern package
registry, a multi-core ready actor-model runtime, a whole new
standard library, and first-class support for agentic work.
Riot is also a tool: riot — and it's the only tool
you need in this stack.
It covers your usual SDLC needs:
Agent friendly
Riot ships with agent-facing instructions, not just human
docs. The riot-ml skill tells agents how to use
the stack, which commands to prefer, where workflows live, and
how to keep package discovery grounded in pkgs.ml.
Every new Riot project created with riot init includes an .agents folder with the Riot skill already there. Start the project, then use your agent.
The local skill explains how to build, test, benchmark, run, format, fix, fuzz, and maintain Riot projects.
Riot commands prefer structured output with --json, so agents can inspect build results, diagnostics, test runs, package metadata, and registry flows without scraping prose.
The skill links deeper workflow references for testing, fuzzing, benchmarking, snapshots, and package lookup, so agents can run the right loop instead of guessing.
/llms.txt is the public discovery map for agents that find Riot from the web; inside a Riot workspace, the local skill is the starting point.
Start with agents included
A new Riot workspace already has the local agent instructions it needs.
$ riot init app
$ cd app
$ ls .agents/skills
Use structured command output
JSON output turns command results into data an agent can route, summarize, or repair from.
Riot is for building OCaml software as one piece: tools, services,
databases, packages, experiments, and systems that need to stay
understandable while they grow.
Multi-core applications
Build actor-oriented systems on top of the runtime in
std/runtime and the actor interface exposed through
std/actor. Spawn work, supervise it, and let Riot use
the cores you have.
Command line interfaces
Build fast CLIs with structured output, clear errors, and the kind
of terminal behavior agents and humans can both drive.
Cloud and networked services
Use actors, supervision, message passing, and a practical standard
library to build services that do real IO. The std/IO
surface includes ioSlice for zero-copy operations
when bytes need to move without extra copying.
Developer tooling
Write formatters, linters, code generators, release tools,
migration scripts, and project automation with the same toolchain
they plug into.
TUI applications
Build terminal interfaces with Riot packages like
minttea and gooey: structured state,
keyboard-driven UI, and native terminal ergonomics.
Web applications
Build web surfaces with suri, including LiveView
support in suri/liveview, typed domain logic, and
agent-friendly APIs without giving up the ergonomics of OCaml.
Database-backed systems
Build typed database flows with sqlx, connect to
PostgreSQL through postgres, and use
sqlite when the right database is a local file.
Agentic workflows
Create workflows that can be run, inspected, repaired, and
repeated by agents: JSON output, stable diagnostics, clear command
boundaries, and recoverable failure modes.
