Anthropic blocks Claude Code from rebuilding existing games

Key Points

1. Anthropic confirmed Claude Code now declines to recreate specific existing games, citing its intellectual property usage policy.
2. The restriction was added via two prompt sentences on Opus 5.5 and cannot be disabled by users.
3. Indie studios including Digital Sun have pulled public demos over fears of AI-generated copycats launching first.

The latest:

Claude Code will no longer rebuild other people’s games, Anthropic confirmed, saying that using Claude to infringe intellectual property breaches its usage policy. The restriction arrived as two added sentences in the tool’s prompt on Opus 5.5, and users cannot switch it off. Game Developer reported the change, which follows weeks of alarm among independent developers over AI-assisted clones reaching storefronts first.

Details:

• The wording: According to Game Developer, the instruction tells the model to build original games, genre games and games from a user’s own designs and assets, while refusing to recreate a specific existing game even if it is renamed or presented as original. Users cannot turn the rule off.
• How it surfaced: An X user called Chasm first noticed the rule, saying it was pushed around October 27 under an internal flag named tengu_heron_brook. Anthropic has not published a separate announcement detailing the rollout or the flag.
• Anthropic’s framing: An Anthropic spokesperson pointed reporters to a statement on X by Addy Osmani of the company’s technical staff, who said two sentences were added to Claude Code’s prompt on Opus 5.5 to steer it away from recreating someone else’s specific game. Osmani said original and genre games “are meant to keep working”.
• Iteration promised: Osmani added that Anthropic would keep iterating to strike the right balance. He set no timeline for further adjustments, and did not describe how the company will measure whether the restriction is calibrated correctly.
• Overreach reported: The rule does not always behave as intended. A developer at Conflict Simulations LLC said in a GitHub issue that Claude refused to work on board-wargame adaptations he described as licensed. The cause of those refusals remains unclear.
• The workarounds: Game Developer noted that safety limits on AI tools can often be bypassed with carefully phrased prompts, and that anyone determined to produce clones can move to open-weight models that carry no comparable restrictions.
• The clone wave: PC Gamer linked a recent surge of rapidly produced clones and decompiled games on Steam and Roblox to the release of Claude Opus 5.5. That wave pushed independent studios to reconsider how much unreleased work they expose publicly.
• Demos cancelled: Digital Sun, the Valencia studio behind Moonlighter, cancelled a public Steam playtest for its game ReVamp, citing concern over games being reverse-engineered, cloned and published before the original is out. Alliance Arts has also held back a planned demo over cloning fears.
• The new schedule: Digital Sun instead opened a smaller Discord playtest on 29 October, and hopes to run a public test around January, ahead of a launch set for 25 March 2027. The studio said showing games early is how indies get seen and find the fans who sustain them.
• Storefront pressure: Developers have asked Valve how Steam will prevent clones from displacing their games, and Valve gave developers in South Korea a rare explanation this week. A GamesIndustry.biz opinion piece argued Steam’s open model, where any game can launch after a small fee, is near collapse as AI makes low-quality output cheap.

Between the lines:

The restriction rests on a prompt instruction rather than a platform rule, which is why it both over-blocks and under-blocks: it refused licensed wargame adaptations at Conflict Simulations, while anyone switching to open-weight models faces no limit. Digital Sun’s cancelled playtest shows the commercial cost lands on developers before any fix reaches storefronts.

What’s next

Watch whether Anthropic revises the two-sentence rule after reports of false refusals, whether Valve turns its South Korea explanation into formal Steam policy, and whether Digital Sun opens the public ReVamp test in January.