Silex [Bots | Robot | Code]

Craft a little robot, program it in real C, and watch it dig, build and farm your survival world.

What is Silex?

Silex is a programming and automation game that lives inside your survival world. You craft a small automaton, write its program at a Terminal, and send it off to dig tunnels, raise walls and tend your fields while you work beside it. The code is real C, so every job you finish makes you a better programmer, whether you meant it or not.

Features

A robot with a personality

Your automaton is an animated little machine with a miner's lamp, a drill arm and a glowing screen for a face: it hops when a program succeeds and shakes when it crashes. A Builder Module adds a brick hopper, a trowel and functions to place blocks and read the blocks around it; a Farmer Module adds a seed bag, a hoe and functions to check, plant and harvest crops.

A quest tree full of jobs

A five-step tutorial opens into three branches of jobs, mining, building and farming: 22 of them, from a crossroads, a great gallery or a bridge to spelling SILEX in planks and stone and sowing a whole field. Every job is checked right there in the world, and each reward fuels the next one. Eight Workshop quests walk you through modules, upgrades, Code Scrolls and Program Disks, while advancement-style frames, an on-screen quest tracker and "Quest done!" toasts keep score.

Code Scrolls: loot you can run

Code Scrolls hide in dungeon, temple, village, mineshaft, shipwreck and stronghold chests. Each one adds a ready-made code to your Code Library, from Safe dig to Spiral mine and Build a bridge: 32 codes in all, four of them yours from the start, and F4 drops any of them straight into your program.

Craftable upgrades

Ten hardware upgrades to craft and install: Processors up to 50,000 operations per tick, Motors that make moves and digs up to three times faster, a Sensor Module that sees 16 blocks around, and Cargo Bays up to 52 slots. The part you replace comes back to you.

A real code editor, in game

Syntax colours, completion, errors explained as you type, several files per project, find and replace, dark, light and high-contrast themes. When something goes wrong, set breakpoints, step line by line, or open the Black Box and rewind the run to see exactly what happened.

Program Disks

Happy with a program? Save it on a Program Disk, crafted from a copper ingot over a sheet of paper, and load it into another automaton or Terminal.

A story to play through

Open the Story tab and ARCHIVE calls on you to wake the Founders' dormant automata and undo the Glitch's sabotage, across 54 missions: the eight chapters of act 1 and its final Examination, then the opening of act 2. Every mission plays out in your own arena, with stars to earn and hidden tests to pass, and unlocks new skills and Codex pages.

Advancements and stats

Press L for a Silex tab of 63 advancements, six of them hidden jokes, plus five new statistics and a one-line report after each run in your world: time, blocks changed, items gathered.

The Codex, your in-game manual

33 lessons, from first steps to pointers, plus a sheet for each of the 34 robot functions and 13 C library functions, open as you progress (all at once with the story off). Run their examples in place with Try it. Recipes and your Code Library are one click away.

A taste of the code

A whole program, ready to paste into a Terminal:

#include <silex/bot.h>

// Dig a 10-block tunnel and party at every coal ore.  
int main(void) {  
    int coal = 0;  
    for (int i = 0; i < 10; i++) {  
        if (bot_look() == BLOCK_COAL_ORE) {  
            coal++;  
            bot_emote(EMOTE_PARTY);  
        }  
        bot_dig();  
        bot_move_forward();  
    }  
    bot_say("Tunnel done!");  
    return coal;  
}

Press F5 and your Miner digs ten blocks ahead, celebrates every coal ore in its path, says "Tunnel done!" and reports its coal count as its exit code.

Getting started

1. Install Fabric Loader and Fabric API for Minecraft 26.2, then drop Silex into your mods folder (on the server too, if you play on one).
2. Gather 8 glass, 9 copper ingots, 1 iron ingot and 9 cobblestone: no redstone needed. Every Silex recipe is in your recipe book, and the Codex tab's Recipes page shows each grid.
3. Craft a Terminal, a Miner and a Construction Beacon. Place the Terminal, the Miner within 16 blocks of it, and the beacon where the Miner will work: it digs and builds only within 16 blocks of your beacons.
4. Open the Terminal, write your program and press F5 to run it. F4 lists every function your robot knows, F1 shows every shortcut.
5. Press K to open the Silex hub and follow the Quests tab, starting with the tutorial.
6. Open chests for Code Scrolls, and craft a Builder Module or a Farmer Module to teach your Miner new tricks.

For teachers and learners

Silex is a game first, and a serious one under the hood. Programs are real C23, compiled by Silex's own compiler and run on SilexVM, a sandboxed virtual machine, with the same type sizes and layouts as gcc and clang on 64-bit Linux. Most of the standard is in, and the few gaps (bit-fields and variable-length arrays among them) are documented. The story introduces the language chapter by chapter, from sequences and loops to arrays, bit operations and pointers, with errors explained in plain words, detection of undefined behaviour, and stars for fast, concise code.

In singleplayer, every Terminal's files are also mirrored to your disk with the real headers, so learners can switch to their favourite editor (VS Code with clangd, for example) when they are ready.

Requirements

• Minecraft 26.2 (Java Edition)
• Fabric Loader 0.19.5 or newer
• Fabric API for 26.2 (built against 0.160.0+26.2)
• Java 25
• Install on the client and the server; singleplayer works out of the box
• Languages: English and French

Silex is in beta: back up your worlds, and tell us about anything odd on the issue tracker.

FAQ

Do I need to know C?
Not at all. Every new Terminal starts with a working program that says hello and steps forward, and the tutorial quests build from there. F4 inserts any function with one click, the Code Library hands you ready-made programs, and the Codex explains everything along the way.

Can I play with friends?
Yes. Every player has their own automata, quests, Code Library and story progress, and each mission runs in its owner's arena. A shared Terminal runs your own robot, robots only dig and build within their owner's Construction Beacon zones, and they never dig Silex blocks.

Will it lag my server?
Programs run on a small pool of worker threads, and every automaton has a cycle budget per tick; a watchdog stops a loop that makes no progress. Server owners can also cap the total time player code gets per tick, size the thread pool, or turn the story off, all in config/silex-server.properties.

Is it safe to let players run code?
That is what it is built for. Player code runs inside SilexVM, a sandbox written in pure Java: every memory access is bounds-checked, and there is no native code, no reflection, and no access to the host's files, network or processes. Automated architecture tests enforce those rules on every build.

Can I use my own code editor?
In singleplayer, yes. Every Terminal's project is mirrored to a folder on your disk with the real headers; save a file in your editor and the Terminal picks it up within seconds.

NeoForge, Forge or Quilt?
Silex runs on Fabric for now. A NeoForge version is planned.

Can I play without the story, or in creative?
Yes. A server, or your own game in singleplayer, can set story.enabled=false for pure survival programming: quests keep working and every Codex page opens. In creative, a Workshop Beacon builds a furnished room with a Terminal, the Mission Board, the Skill Tree, the Codex and a Miner ready to go.

Licence

Silex's code is licensed under Apache-2.0; its content (missions, Codex text, dialogue, documentation and images) under CC BY 4.0. The editor's optional dyslexia-friendly font, OpenDyslexic, is included under the SIL Open Font License 1.1. The mod jar also bundles ICU4J, Jackson and a few other open-source libraries, each credited with its licence in the jar's NOTICE file. Copyright 2026 The Silex Authors.

Credits

• Silex is made by cedr0u.
• OpenDyslexic font by Abbie Gonzalez.
• Screenshots and trailer: the Complementary Reimagined shader pack by EminGT, on Iris and Sodium.
• Trailer music: “Sparker of Ideas” by Lesiakower, from Pixabay (Pixabay Content License).

Your automaton is waiting. Give it its first line of code.

NOT AN OFFICIAL MINECRAFT PRODUCT. NOT APPROVED BY OR ASSOCIATED WITH MOJANG OR MICROSOFT.