Anthropic confirmed on Oct. 30 that it told Claude Code to stop rebuilding specific video games1. The rule had already been running for three days before anyone outside the company said a word about it2.
Addy Osmani, a member of Anthropic's technical staff, explained the change on X. "We added two sentences to Claude Code's prompt on Opus 5.5 to steer it away from recreating someone else's specific game because using Claude to infringe IP is against our usage policy," he said1. His post answered a discovery that had already spread across the gaming side of X.
Anthropic Took 3 Days to Confirm Claude Code's New Rule
Dated steps from the rule's first appearance in Claude Code to Anthropic's public confirmation, October 2026
The first pin is the day chasm reported the rule already running inside Claude Code; the second pin is the day Addy Osmani confirmed it on X.
Sources: Addy Osmani (@addyosmani) on X [1]; chasm (@chasmmmmmmmmmmm) on X [2]. Chart by Kelly Dennis.
The numbers behind this chart
| Date | Event |
|---|---|
| Oct. 27, 2026 | Rule appears. Server-delivered, missing from the changelog |
| Oct. 30, 2026 | Anthropic confirms. Osmani replies to chasm's post |
Two Sentences, Sent Quietly
A user posting as chasm found the rule first2. It arrived under a flag named tengu_heron_brook, sent straight from Anthropic's own servers. That is how a company often pushes a quiet update to a live product, between one release and the next.
Claude Code's changelog skipped the change entirely. The rule stayed fixed in place, permanent across every settings menu Claude Code offers2.
Anthropic wrote the rule itself. Chasm's post captured its exact words: "Do build original games, games in a genre, and games from the user's own designs and assets. Don't build a recreation of a specific existing game, even if it is renamed or called original"2.
A usage policy is the set of rules a company writes to limit what someone can do with its product. Anthropic bars Claude from helping anyone break copyright or other intellectual property law. This rule enforces that line inside one specific tool. That line already existed in writing, long before chasm found this new sentence inside it.
chasm@chasmmmmmmmmmmmANTHROPIC IS CRACKING DOWN ON VIDEO GAME REWRITES 🚨
Claude Code picked up a new rule around Oct 27, sent from Anthropic’s servers under a flag called "tengu_heron_brook". There’s no setting to turn it off.
The full rule: “Do build original games, games in a genre, and games… pic.twitter.com/0Zc5mQWHJt
Weeks of Clones Pushed It
The rule followed weeks of complaints from game developers3. Alliance Arts canceled the public demo for its coming Steam game, Drunken Goddess Reflux. The studio worried its content "could be used to quickly imitate or replicate the game's presentation and gameplay with AI".
Other developers had pressed Valve, which runs the Steam store, about the same flood of copies3. Steam's most recent Next Fest doubled its showcased demos over the one before it, and AI-assisted games drove most of that growth4.
A single studio's canceled demo turns into a pattern fast once a storefront doubles in size over one season. Each new entrant weighs the same choice Alliance Arts made. Show the work and risk a copy, or hold it back and lose the audience a demo earns.
Two Answers to One Problem
Osmani said the rule leaves most games untouched. "Original games, genre games, and games built from your own designs and assets are meant to keep working," he said1. He also left an opening for mistakes: "We'll continue to iterate to ensure we're striking the right balance. In the meantime, if Claude turns down something that's yours, send it my way".
Valve answers the same complaint on different ground. Tom Giardino, speaking for Valve at Steam's Indie Connect event, framed Valve's stance plainly: the company stays clear of acting "to be gatekeepers telling developers which tools they should or shouldn't use"4.
Giardino pointed developers toward their own work instead. A game stays ahead of its copies, he said, only when its maker keeps "growing your game by adding features, personality and creativity that stem from your own perspective"4.
One company changed its own product. The other told developers to out-build the problem themselves. Both leave an already-shipped clone standing exactly in place.
The split matters past this one rule. A developer chasing a fix from Anthropic waits on a prompt change reaching every model Claude Code runs. One chasing a fix from Valve instead waits on their own studio alone, for better and for worse.
What the Rule Misses
Claude Code still relies on the user's own claim about who owns the game they're building3. Models that run on a person's own computer answer to a rule book someone other than Anthropic wrote.
Game Developer's own reporting noted that clever prompts have bypassed safety limits on AI tools before. A cloner determined enough could switch to a model built under an entirely different rule book6.
One paid side effect surfaced fast. A developer builds digital wargame modules for clients who already own the physical games. That developer filed a complaint on Anthropic's own code repository on Oct. 30. Sessions that had done this work for months began refusing it, once the new rule arrived5.
The complaint asked Anthropic for three fixes5. A narrower rule topped the list, aimed only at real infringement.
Next came a verification path, a way for a paying professional to prove ownership. Documentation came last: a changelog entry for a change this size. Each of the three sat unanswered by Oct. 31.
All 3 of the GitHub Complaint's Requests Sit Unanswered
Requests in the Oct. 30 complaint against Claude Code's new rule, by whether Anthropic had answered each one as of Oct. 31, 2026
Each cube is one request the complaint made to Anthropic; every cube stays magenta because all three sat unanswered as of Oct. 31.
Source: GitHub (anthropics/claude-code, issue #106167) [5]. Chart by Kelly Dennis.
The numbers behind this chart
| Item | Value |
|---|---|
| Unanswered requests | 3 |
| Whole | 3 |
What to Do
Does your team use Claude Code anywhere near a game, a mod, or licensed creative assets? Test a real project against the new rule before a client deadline does it for you. Report a refusal on legitimate work to Osmani directly, the way he asked. Switching tools on the spot skips a fix that might already be underway.
Keep a record of what your vendor's AI tool blocks and why. A rule this narrow can still catch work meant to stay untouched, and a saved example speeds up any appeal.
By the Numbers
- 2 sentences: what Osmani said joined Claude Code's prompt on Opus 5.51.
- 3 days: how long the rule ran before anyone outside Anthropic said a word, Oct. 27 to Oct. 3012.
- 1 flag: tengu_heron_brook, the name attached to the server-delivered change2.
- 0 of 3: the GitHub complaint's requests answered by Oct. 315.
- Roughly 2 times: how much Steam's most recent Next Fest grew its showcased demos over the one before it4.
What to Watch
Watch whether Anthropic builds the verification path the GitHub complaint asked for5. That would be a way for a paying professional to prove they own the game they're building. A rival coding tool adopting a matching rule, or leaving the door open on purpose, deserves the same attention. Valve's next move matters just as much: a storefront that currently declines to screen tools may yet turn to screening games instead.
Sources
- Addy Osmani (@addyosmani), post on X, Oct. 30, 2026, https://x.com/addyosmani/status/2116213240363729013
- chasm (@chasmmmmmmmmmmm), post on X, Oct. 30, 2026, https://x.com/chasmmmmmmmmmmm/status/2116062991686721968
- Callum Doyle, "Anthropic adds new Claude rule banning recreations of existing games," Dexerto, Oct. 31, 2026, https://www.dexerto.com/gaming/anthropic-adds-new-claude-rule-banning-recreations-of-existing-games-3423516/
- Rick Lane, "Anthropic updates Claude to 'steer it away' from letting users clone games following weeks of Steam being inundated with AI slop," PC Gamer, Oct. 31, 2026, https://www.pcgamer.com/gaming-industry/anthropic-updates-claude-to-steer-it-away-from-letting-users-clone-games-following-weeks-of-steam-being-inundated-with-ai-slop/
- lerugray, "[URGENT] Server-delivered "games" instruction blocks professional development work," GitHub issue #106167, anthropics/claude-code, Oct. 30, 2026, https://github.com/anthropics/claude-code/issues/106167
- Bryant Francis, "Anthropic appears to have ordered AI tool Claude to stop remaking video games," Game Developer, Oct. 30, 2026, https://www.gamedeveloper.com/programming/anthropic-appears-to-have-ordered-ai-tool-claude-to-stop-remaking-video-games
