What can someone actually build with Claude Code? Beau Johnson's 20-build countdown ranges from small marketing tools and games to printed hardware, a shopkeeping experiment and a C compiler. The useful pattern is not one magic prompt. It is a loop: give the agent a concrete job, let it inspect a result, then test the result in the real environment.
For a first build, copy the method, not the spectacle: choose one small workflow, give Claude a visible output and a test, then review it yourself. The shelf hook needed a real print; the ad workflows still need a human approval; and the compiler needed an engineered test harness. Those details matter more than the countdown ranking.
Watch the 20-Build Countdown
The countdown includes a sponsor segment. Product demonstrations and maker-reported numbers are attributed to their builders below; they are not independent performance tests by JQ AI SYSTEMS.
Source Note: What We Checked
Prepared 8 November 2026 from the supplied transcript and video. We checked the linked primary material for the compiler, Project Vend, the meter, TV cleanup, the printed hook and Anthropic's legal, marketing and sales stories. We did not rebuild the projects, run the games, repeat the bridge load test or audit financial claims. Other entries are the builders' demonstrations as presented by Beau.
The provided X status links end mid-ID and cannot safely identify a particular post. For those entries, the builder link opens the creator's X profile, while the watch link jumps to the exact clip in Beau's video. Where a full maker article or repo was verifiable, it replaces a profile link.
All 20 Builds, From 20 to 1
This is the video's order, not a ranking of software quality. Each row separates the build from the practical limit worth noticing.
#20 to #16
| Build and builder | How Claude was used | Builder note | Watch / source |
|---|---|---|---|
| #20 Static ad generator Mike Futia | A product photo and brand kit become many ad concepts. Claude Code builds the workflow; an image model makes the graphics. | Creator demo, not evidence of ad performance. | Watch 20 Builder on X |
| #19 Backcountry 101 Dilum Sanjaya | An interactive 3D survival-learning experience made with Claude. | Try the lesson flow before judging it as a teaching tool. | Watch 19 Builder on X |
| #18 A Miami game that plays itself Prasenjit | Claude Code builds a browser game, adds a mission, then drives and records its own playthrough. | A recorded playthrough is not a full gameplay test. | Watch 18 Builder on X |
| #17 Meta ads approval assistant Tobi | A skill reviews ad data twice a day and proposes changes, with a human approval gate and budget bounds. | Keep budget changes and publishing under explicit approval. | Watch 17 Builder on X |
| #16 Low-cost robot leader arm TaraT | Claude helps design a hand-moved SO-100 leader arm using encoders, printable parts and a PCB. | Mechanical fit, electrical safety and calibration still need bench testing. | Watch 16 Builder on X |
#15 to #11
| Build and builder | How Claude was used | Builder note | Watch / source |
|---|---|---|---|
| #15 AI game master for the family Meng To | Claude acts as a Dungeons-and-Dragons-style game master in a tabletop adventure made for his children. | The storytelling demo is more useful than any claim of general game autonomy. | Watch 15 Builder on X |
| #14 Legal team tools Mark Pike, Anthropic | A non-coding lawyer builds an AI-routed payphone and legal-review workflows with Claude. | Anthropic says lawyers still make the final legal judgment. | Watch 14 Maker source |
| #13 Claude-log chip fab An Xuan | A 3D chip-fab metaphor replays Claude Code sessions as moving work through a factory. | A visualization helps inspect work; it does not certify its quality. | Watch 13 Builder on X |
| #12 3D-printed shelf hook Wataru Takasato | Claude writes OpenSCAD, renders previews and exports an STL; the maker prints and tests the fit. | The first print had undersized holes and needed physical correction. | Watch 12 Maker source |
| #11 Growth-marketing ad factory Austin Lau, Anthropic | A Figma plugin and CSV workflow produce creative and search-ad variants from human-supplied copy. | Anthropic reports faster drafting, with manual review before upload. | Watch 11 Maker source |
#10 to #6
| Build and builder | How Claude was used | Builder note | Watch / source |
|---|---|---|---|
| #10 Mech shooter Meticulai | A month-long game build combines Claude with other art and audio tools. | A polished clip does not reveal playtesting or production readiness. | Watch 10 Builder on X |
| #9 CRM from one prompt Adonias | One foundation agent and parallel specialists build a CRM against visual references. | The maker still reviews screenshots and revises the result. | Watch 9 Builder on X |
| #8 TV cleanup Ansub | Claude helps identify and disable unwanted Android TV packages over owner-enabled debugging. | Related CleanYourTV repo documents reversible changes; verify your exact TV model first. | Watch 8 Builder on X |
| #7 The Nakama sales crew Shahboz Ibragimov, Anthropic | Scheduled agents sort leads, update Salesforce and draft bilingual replies; a coordinator updates instructions. | The rep reviews drafts before sending. Time savings are self-reported. | Watch 7 Maker source |
| #6 Iron March and its trailer Bayard | Claude builds a roguelite and reportedly renders a trailer frame by frame using a virtual game clock. | Treat the build time and no-keyboard claim as the maker's report. | Watch 6 Builder on X |
#5 to #1
| Build and builder | How Claude was used | Builder note | Watch / source |
|---|---|---|---|
| #5 3D-printed bridge test Roberto Nickson | Models design bridges under common print constraints; the team prints and load-tests them. | About 130 lb for Claude's bridge is the team's estimate, not structural certification. | Watch 5 Builder on X |
| #4 Project Vend, phase two Anthropic / Andon Labs | A shopkeeping agent gains a CEO and a merchandise agent, with agent-to-agent Slack coordination. | Anthropic reports improved profitability, but questions whether the CEO helped. | Watch 4 Maker source |
| #3 26 agents, one multiplayer game Jacob | Twenty-six Claude agents reportedly build a playable multiplayer heist game overnight. | A live game is a stronger demo than a render; stability still needs real players. | Watch 3 Builder on X |
| #2 Claude's C compiler Nicholas Carlini, Anthropic | Sixteen Opus 4.6 agents work in parallel on a Rust compiler across nearly 2,000 sessions. | Carlini built the harness and tests; the repo warns the code is not validated. | Watch 2 Maker source |
| #1 121GW multimeter firmware Dave Jones, EEVblog | Claude-assisted reverse engineering turns meter firmware into GCC-buildable C, then it is flashed and tested on a real meter. | The maker repo documents emulation and device tests; do not flash a meter without a recovery plan. | Watch 1 Maker source |
What These Builds Actually Teach
The strongest agents see a result, not just a prompt. Claude rendered the hook before a human printed it; the game trailers used actual frames; the compiler had a test harness. Anthropic's compiler account is especially clear: Nicholas Carlini designed the environment and verifiers, and the agents iterated within it. The original February write-up reported no custom assembler or linker; the current repo has since evolved, so those are different snapshots of the project.
Physical tests expose the gap between plausible and usable. The hook maker's own write-up records a failed first fit and drilled holes. Dave Jones's firmware repo documents emulation and meter testing. Roberto Nickson's bridge result is a creator-run comparison, not a certified structural test. These examples invite replication with measurements, not blind trust in a video clip.
Useful business automation keeps authority legible. The ad assistant proposes rather than spends; Anthropic's marketing workflow sends copy to manual review; its legal workflow routes final decisions to lawyers. In Project Vend, adding a CEO agent did not automatically make the shop better. More agents are an architecture choice, not a quality guarantee.
Which Build Should You Try First?
| Your bottleneck | Start with | First proof |
|---|---|---|
| Repetitive content variants | #20 or #11 | Ten drafts that meet brand and format rules, manually approved before publishing. |
| An awkward physical replacement part | #12 | A measured fit after one test print; record tolerances and orientation. |
| A routine internal handoff | #7 or #17 | A week of correctly prepared drafts with no unapproved sends or budget moves. |
| A creative coding idea | #15 or #18 | A playable five-minute loop tested by someone other than the builder. |
We would not begin with a firmware flash or a 26-agent overnight run. Those are compelling research and maker stories, but the smallest repeatable workflow gives you faster evidence about whether Claude actually helps you.
Primary Sources, Repos and Builder Feeds
Research and company workflows: Carlini's compiler account · compiler repo · Project Vend phase two · legal team · growth marketing · Nakama sales agents.
Builds you can inspect: 121GW firmware · CleanYourTV (reversible owner-enabled TV changes, not firmware flashing) · OpenSCAD hook build log.
Creator X profiles: Mike Futia · Dilum Sanjaya · Prasenjit · Tobi · TaraT · Meng To · An Xuan · Meticulai · Adonias · Ansub · Ryan Doyle · Bayard · Roberto Nickson · Jacob · EEVblog. These are profile links, not purported exact demo posts.
X may block an embedded feed in some browsers. The direct builder links and timestamped video clips above remain available as fallbacks.
Video Chapters
Opening and #20-#16
| Time | Segment |
|---|---|
| 00:00 | One prompt, a whole firmware |
| 00:31 | #20 A hundred ads from one photo |
| 00:58 | #19 A 3D survival school |
| 01:23 | #18 The game that plays itself |
| 01:49 | #17 The ad manager that waits for approval |
| 02:31 | #16 A robot arm from cheap parts |
#15-#11
| Time | Segment |
|---|---|
| 03:00 | #15 An AI game master for his kids |
| 03:24 | #14 The lawyer who cannot code |
| 03:54 | #13 A chip fab made of Claude Code logs |
| 04:24 | #12 The printed shelf hook |
| 04:58 | #11 Anthropic's ad factory |
#10-#6
| Time | Segment |
|---|---|
| 05:34 | #10 A mech shooter in a month |
| 05:54 | #9 A CRM from one prompt |
| 06:28 | #8 The TV cleanup |
| 07:01 | #7 The Nakama sales crew |
| 07:37 | #6 The game that filmed its own trailer |