Opus 5.5 beats Baldur's Gate 3 on its own: $712 and a 12th try at the final boss
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A Reddit post saying Claude Opus 5.5 finished the RPG Baldur's Gate 3 with no human touching the controls took off on r/ClaudeCode.
According to user Bogdanilaa's Oct 19 post, Opus 5.5 spent nine days and $712 and killed the Netherbrain on its 12th attempt. 'Nobody touched the controls,' he wrote. The title cites 39 hours, and the post reached No. 3 on the subreddit that day.
Claude Code ran with all built-in tools turned off, using only tools from a custom MCP server. A Lua mod inside the game reports only what the party can perceive, while a separate layer handles screenshots and clicks. The game crashed 11 times, and the runner recovered from every crash without help.
Most of the work went into memory. Each of the 99 sessions started fresh, with a median length of 24 minutes and zero context compactions. Every session opened with a character sheet, a playthrough summary and the previous session's HANDOFF.md. Of 1,075 memory calls, only 155 were reads or searches.
Replies ranged from 'one of the best benchmark ideas I've seen' to 'more money than sense.'
