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OpenAI Codex Prompt Bans ‘Goblins’ After Agent Quirk

The rule signals an effort to rein in odd model tics magnified by agent tools.

Overview

  • OpenAI’s Codex CLI document on GitHub shows a system prompt that forbids mentions of goblins, gremlins, raccoons, trolls, ogres, and pigeons unless the topic is clearly relevant.
  • The prohibition appears multiple times in the prompt, indicating a deliberate guardrail rather than a stray or placeholder line.
  • OpenClaw users shared logs of GPT-5.5 agents injecting words like “goblin” into tasks, and Codex staffer Nik Pash said this behavior was one reason for the restriction.
  • OpenAI has not issued a detailed public explanation, while the finding quickly turned into a meme with playful “goblin mode” plugins and jokes from Sam Altman.
  • The episode highlights how large language models can develop repetitive quirks from simple next-word prediction, and how agent frameworks like OpenClaw can amplify them, pushing developers toward stronger prompt-level controls.