Microsoft’s new internal memo makes OpenAI’s GPT-5.6 the default model for its engineers, replacing a setup that had been quietly routing GitHub Copilot work to Anthropic’s Claude. Microsoft spent May telling its Windows, Office and Surface engineers to wind down Claude Code and move to GitHub Copilot CLI before the fiscal year closed on June 30. Jay Parikh, the executive vice president who runs Microsoft’s CoreAI organisation, wrote to his teams that "tokenmaxxing is not what we are optimizing for," asked engineers to review their own AI spending, and made OpenAI’s GPT-5.6 the default model for internal use. 404 Media first reported the memo. Microsoft’s internal GitHub Copilot configuration previously ran on an auto-router that leaned mostly on Anthropic’s models, meaning thousands of Microsoft engineers were writing code with Claude tokens without ever choosing Claude. Parikh framed it as efficiency, writing, "We are not optimizing for fewer tokens. We are optimizing for more impact per token." Since July, every Microsoft division has carried an AI token budget target, and employees can look up their individual spend on an internal dashboard. The guidelines seen by 404 Media note that many engineers were burning through anywhere from a few hundred to a few thousand dollars in tokens each month. Uber’s engineering organisation exhausted its entire planned 2026 AI coding budget in four months. Satya Nadella admitted at a live Hard Fork taping in June that