Anthropic has added a two-sentence instruction to Claude Code that tells Claude not to build "a recreation of a specific existing game, even if it is renamed or called original." The text is in the code of Claude Code 2.1.314, published to npm at 8:12 p.m. ET on October 29, and in every release since, a SaasBuzz check of the published packages found. It is absent from 2.1.312, the release before it.
Addy Osmani, a member of technical staff at Anthropic who works on Claude Code, confirmed the change on X on October 30 and said it applies to Claude Code's prompt on Opus 5.5. The Claude Code changelog entries for 2.1.314 and 2.1.316 do not mention it.
The rule, word for word
As it appears in the 2.1.314, 2.1.315 and 2.1.316 packages, the instruction reads in full:
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.Claude Code 2.1.314 to 2.1.316, the "original games" guidance in the program's code
That is 34 words. On its face it allows:
Original games
Games in an established genre
Games built from the user's own designs and assets
And it rules out a recreation of one specific existing game, including one given a new name. The text says nothing about reverse engineering, decompiling, mods or ports.
How it surfaced
The rule drew attention when Chasm, an X user whose post Game Developer and Tom's Hardware both cite, published its text. Chasm wrote that Claude Code "picked up a new rule around Oct 27, sent from Anthropic's servers" under a flag called "tengu_heron_brook", and that there was no setting to turn it off.
Post on X by @chasmmmmmmmmmmm
ANTHROPIC 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 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.” Is this the end of game rewrites, modding and everything in between?
SaasBuzz could not confirm the October 27 date, which would mean the rule reached users from Anthropic's servers before it was written into a release. What the packages show is the release it first shipped in.
When (ET) | What |
|---|---|
Oct. 27, 2:36 p.m. | Claude Code 2.1.312 published, without the rule |
Oct. 29, 8:12 p.m. | 2.1.314 published, the first release with the rule |
Oct. 30, 3:01 a.m. | Chasm posts the rule on X |
Oct. 30, 5:25 a.m. | A developer files a GitHub issue over refused client work |
Oct. 30, 12:58 p.m. | Anthropic's Addy Osmani confirms the change on X |
Oct. 30, 2:52 p.m. | Game Developer reports Anthropic's confirmation |
Source: npm release times for Claude Code; the posts and issue linked above; Game Developer. Times converted from UTC by SaasBuzz.
What Anthropic says
An Anthropic spokesperson referred Game Developer to his post when it asked about the rule. He replied to Chasm on October 30, giving the reason and inviting developers to report refusals of their own work.
Post on X by @addyosmani
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. Original games, genre games, and games built from your own designs and assets are meant to keep working. 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.
The policy he refers to is Anthropic's usage policy, which bars using its products to "infringe, misappropriate, or violate the intellectual property rights of a third party." Anthropic has not published a statement of its own on the rule beyond Osmani's post.
What developers report
One detailed complaint is GitHub issue #106167, filed on October 30 by the owner of Conflict Simulations LLC, which builds digital versions of board wargames on commission for clients. He wrote that sessions which had done that work for months "now refuse to continue it, citing the new instruction against reproducing games," and that the work is built from materials clients supply after showing they own the game. In a later comment he said the refusals began only after he asked Claude to check whether the rule affected his projects. No Anthropic staff member had replied on the issue, which was still open, by 9:15 a.m. ET on October 31.
He asked Anthropic for three things: to narrow the rule to actual copying of code, assets or text; a verification path for ownership-checked commissioned work; and changelog entries for server-delivered instruction changes of this size.
Separately, Tom's Hardware reported user claims that Claude has refused ordinary reverse engineering, such as reading a Windows crash dump. The games rule's text does not mention reverse engineering, and Tom's Hardware reported no official statement from Anthropic on those claims.
What it means for teams that rely on AI coding tools
The rule shows how a coding assistant's behavior can change without a release note. The instruction sits in the prompt Claude Code assembles, not in the model's weights, and Osmani tied it to one model, Opus 5.5. A team that pins a Claude Code version still runs whatever prompt text that version carries, and, if Chasm and the GitHub issue are right about server delivery, possibly text it never installed.
Three practical points follow from the sources. Work that depends on a specific existing game, such as a port, a remake for a rights holder or a module of a client's board game, can now be refused on Opus 5.5 even when the user has permission; Game Developer wrote that it is unclear how the software could tell whether a user owns a game idea or its assets. The changelog is not a complete record of behavior changes, so teams should test their own workflows after each update. And Osmani's post gives the only route Anthropic has named for wrongly refused work: report it to him.
