Anthropic confirms Claude Code game-clone rule; users report wider refusals

Since Unicorn API’s first report on Claude Code’s game-recreation rule, the story has widened from games to reverse engineering. Developers now report that Claude Opus 5.5 in Claude Code refuses reverse-engineering tasks it previously handled, and Tom’s Hardware says it has received direct confirmations of those refusals. At the same time, the rule itself is better documented: XDA independently found it in the Claude Code binary, according to Ars Technica.

The core fact is unchanged. Anthropic’s Addy Osmani confirmed on X that the company “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”. The reverse-engineering refusals, by contrast, remain user reports that Anthropic has not addressed in any source available.

What Anthropic has confirmed, and what it has not

Osmani’s post is dated October 30, 2026. Tech Times UK describes him as a member of Anthropic’s technical staff, while Ars Technica calls him an Anthropic software engineer. His post sets out what the change is meant to allow:

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.

That quote appears in full in both Tom’s Hardware and Ars Technica. What the post does not do is publish the two sentences. Tom’s Hardware notes that “there’s no telling what those sentences might be,” while suggesting they may match a screenshot posted by X user Chasm. Business Today likewise states that the Chasm wording has not been officially confirmed by Anthropic.

The wording Chasm shared reads: “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.”

Osmani’s post also does not mention reverse engineering. In the sources, the confirmed scope is games only.

Claim	Status	Basis
Two sentences added to Claude Code’s prompt on Opus 5.5 against recreating specific games	Confirmed	Osmani’s X post
Exact rule wording	Unconfirmed by Anthropic	Chasm screenshot; XDA binary check
Rule present in Claude Code version 2.1.314	Independently reported	XDA, via Ars Technica
Opus 5.5 refuses reverse-engineering tasks	User reports	Tom’s Hardware; iXBT.games
Rule cannot be switched off	Claim by the user who spotted it	Cited by International Cyber Digest, via Tech Times UK

Reverse-engineering refusals: the new user reports

Reverse engineering means working backwards from compiled software to understand how it functions. Business Today notes it is widely used to understand software, troubleshoot compatibility issues and analyse code for security purposes. According to that outlet, many developers complain that Claude now refuses ordinary, non-malicious reverse-engineering tasks with legitimate uses.

Tom’s Hardware reports direct confirmations of the blocking. One comes from its former staff member Jarred Walton, who was trying to run checks on software he is developing; he says such work ran without issue until October 31. iXBT.games, citing user reports, says Claude Code and Opus 5.5 block requests for harmless reverse engineering, including attempts made with the Reverse Engineer Anything tool.

The connection to the game rule is an inference, not a finding. iXBT.games says the restrictions are “presumably linked” to the new game rule, and Business Today says the restriction “is said to be linked” to the new instruction. No source shows Anthropic explaining the reverse-engineering refusals.

One possibly relevant piece of context comes from the model’s launch. SiliconReport reported that Anthropic deployed Opus 5.5 with tiered safety fallbacks: standard engineering queries remain unhindered, but sensitive cybersecurity requests automatically route to Opus 4.8, with a cybersecurity verification program due to open in the following weeks. None of the sources ties that routing to the new refusals, so it should not be read as an explanation.

Where the rule lives: Claude Code version 2.1.314

Chasm, described by Ars Technica as an AI decompilation enthusiast, noted the change late last week and said the rule seemed to be added on or around October 27. Tech Times UK also dates the first sighting to around October 27. According to Ars Technica, the rule sits in a JSON file under the name “tengu_heron_brook”.

XDA later verified that the rule appears in version 2.1.314 of the Claude Code binary, released on October 30, according to Ars Technica. XDA also reported that the “tengu_heron_brook” entry was used for other purposes in earlier versions, and that Opus 5.5 appeared to have its own separate instructions restricting game recreations in its system prompt bundle. The sources differ slightly on timing: the rule was spotted around October 27, while the binary version XDA examined was released on October 30. The sources do not explain the gap.

On scope, Tom’s Hardware says that, as far as it can ascertain, the game-related blocking is limited to the combination of Claude Code and Opus 5.5. If that holds, it suggests users could sidestep the limit by calling Opus through another harness, such as Ollama, or through a wrapper. That is the outlet’s reading, not a tested result. In a separate account quoted by Tech Times UK, the user who spotted the rule says it comes from Anthropic’s servers and cannot be switched off.

Why the rule is unlikely to stop AI game copying

The restriction arrives during a surge in AI-assisted copying. Ars Technica describes thrown-together copies of game demos that make some developers afraid to show early work publicly, and thousands of AI-powered decompilation and porting projects for retro games. Decompilation turns compiled code back into readable source code.

Ars Technica reports that decomp.dev, a years-old game decompilation community, announced last month that it was shutting down. Maintainer Luke Street wrote that AI tools had warped decompilation “into a hollow numbers game, exacerbated by folks who just want to burn tokens to make number go up or ‘port game to PC,’ all else be damned”.

Tech Times UK points to a game studio’s response: Alliance Arts cancelled the public demo for its Steam game Drunken Goddess Reflux, warning the content “could be used to quickly imitate or replicate the game’s presentation and gameplay with AI”. Business Today reports that some independent developers face extortion attempts from scammers threatening to use AI to clone unfinished demos.

Against that backdrop, Ars Technica argues that the rule is unlikely to have much overall impact. Copiers can switch to other frontier models without such restrictions, or to cheaper open-weight models that are “not all that far behind in capabilities”. Tech Times UK makes a similar point: the rule covers only Anthropic’s own assistant, locally run models are not necessarily bound by the same limits, and there is no systematic evidence on how often Claude Code blocks recreations or wrongly rejects legitimate projects. It also notes that Claude Code cannot independently establish whether a user owns the game they want to recreate.

Ars Technica suggests the more immediate benefit may be to Anthropic, by helping protect the company from potential copyright liability. It adds that decompilation based on reverse engineering generally passes legal muster as long as “expressive elements” such as art and sound assets are not included, with no guarantee that individual users would take that care.

Anthropic is not alone. Business Today reports that OpenAI recently deactivated the account of a user who was trying to modify their television’s software.

What it means for developers building with Claude

For most builders, the confirmed change is narrow: it targets recreations of specific existing games, and Anthropic says original and genre games should keep working. In practice, the reports suggest friction beyond that line. iXBT.games says complaints on the Claude Code GitHub repository describe refusals mid-project, while developing game mechanics, or while fixing bugs. Ars Technica says a handful of GitHub issue reports suggest the prompt is getting in the way of some game development use cases.

Practical points from the sources:

• Scope appears tied to Claude Code with Opus 5.5. Tom’s Hardware’s assessment is that the game blocking is limited to that combination, though this is unconfirmed.
• Reverse-engineering workflows may be affected. Security analysis, compatibility checks and testing of one’s own compiled software are the kinds of work users say are now refused.
• There is a named contact for false refusals. Osmani asked developers to send him cases where Claude turns down something that is theirs.
• The rule may change. Anthropic says it will “continue to iterate” on the balance.

Tom’s Hardware reports that the move has come under heavy fire from the software development community. The open question for teams that rely on Claude Code is whether Anthropic will separate legitimate reverse engineering from game copying, or acknowledge that the two are affected by the same change.

What to watch next

• An Anthropic statement on reverse engineering. So far, the confirmation covers only game recreation.
• Revisions to the prompt. Osmani says Anthropic will keep iterating. Later Claude Code versions may show whether the wording changes.
• The cybersecurity verification program. At launch, Anthropic said a cybersecurity program would follow its life-sciences one. Whether it affects reverse-engineering access is not stated in any source.
• Whether other AI providers follow. Ars Technica’s argument rests on other models remaining unrestricted.
• GitHub issue volume. The developer complaints on the Claude Code repository are the clearest public signal of how often legitimate work is caught.