An OpenAI employee has withdrawn his signature from an amicus brief supporting Anthropic in its legal battle against the U.S. Department of Defense, citing a recent policy reversal by the AI company. Brian Fioca, a member of OpenAI's Go to Market Staff, announced his decision on X, stating he could no longer truthfully argue that Anthropic is not a supply chain risk. The withdrawal follows Anthropic's decision to abandon a controversial safeguard that would have secretly hindered competitors from using its newest AI model, Claude Fable 5.

In March, more than 30 employees from Google, OpenAI, and Google DeepMind filed the amicus brief to support Anthropic's lawsuit against the Department of Defense. The brief urged the court to recognize the ethical commitments of AI developers as contributions to good governance rather than obstacles. However, Anthropic's recent policy shift has prompted Fioca to reconsider his stance, underscoring the tensions between AI safety measures and competitive transparency.

Anthropic initially implemented safeguards in Claude Fable 5 to curb high-risk uses of advanced AI, such as cybersecurity or biological weapons research. While some measures aligned with its safety strategy, a hidden provision aimed at reducing the model's effectiveness for frontier AI research drew criticism. Researchers argued the undisclosed restrictions amounted to a covert handicap on competitors using Claude to develop rival models.

Following backlash from researchers and industry observers, Anthropic reversed the policy, acknowledging it had "made the wrong tradeoff." The company apologized for the lack of transparency and pledged to make the safeguards visible. Critics, however, noted that the incident raised concerns about Anthropic's willingness to embed covert performance degradation into its models, despite terms of service already prohibiting customers from using its systems to train competing AI products.

The controversy has implications for Anthropic's legal standing and its coalition of supporters. Dean Ball, a senior fellow at the Foundation for American Innovation, remarked that defending Anthropic against government overreach would have been more difficult had the policy reversal occurred earlier. The incident highlights the challenges AI companies face in balancing safety, transparency, and competitive dynamics in a rapidly evolving industry.

Anthropic CEO Dario Amodei has warned that increasingly powerful AI systems cannot be safely entrusted to governments or corporations alone, arguing that both require meaningful checks and balances as artificial intelligence becomes more capable. In an essay published Wednesday, Amodei stated that governments should have the authority to block or reverse deployments of advanced AI models that pose unacceptable risks, including threats related to cybersecurity, biological weapons, and loss of control of AI systems. The Anthropic CEO argued that AI companies could eventually develop "quasi-state characteristics," becoming powerful enough to influence society in ways traditionally associated with governments.

Regulatory Proposals

Amodei said existing transparency-focused approaches to AI oversight are no longer sufficient as frontier models become increasingly capable. He called for "more serious and binding regulation of AI" and compared advanced AI systems to airplanes and pharmaceuticals, arguing that they should undergo mandatory third-party testing before deployment. "Their release should be blocked or reversed as a threat to public safety if they do not meet high standards of safety," Amodei wrote. The proposed evaluations would focus on risks related to cybersecurity, biological weapons, loss of control, and automated research capabilities. He added that AI developers should maintain strong security standards, conduct regular testing, and promptly report major safety incidents.

Labor Market Impact

Beyond safety risks, Amodei warned that AI could create larger and more persistent labor-market disruptions than previous technological shifts. "It's reasonable to think that AI could produce much larger disruptions to the labor market than previous technologies," he wrote. To address those risks, Amodei proposed measures including wage insurance, worker-retention incentives, workforce training programs, and expanded monitoring of AI’s impact on employment. He also suggested broader income-support mechanisms could eventually become necessary if displacement becomes widespread. Amodei argued that policymakers should focus on ensuring the benefits of AI-driven economic growth are shared broadly rather than concentrated among a small group of companies and investors.

Civil Liberties and Geopolitics

The essay also addressed concerns about AI’s impact on civil liberties, political power, and national security. Amodei warned that advanced AI could become a tool of surveillance and authoritarian control if governments gain unchecked access to increasingly capable systems. He also called for stronger protections against domestic use of fully autonomous weapons. At the same time, he argued that private companies should not hold unchecked influence over increasingly powerful AI systems, warning that some firms could eventually develop "quasi-state characteristics." On geopolitics, Amodei described AI as a technology comparable in strategic significance to nuclear weapons, arguing that it could become a dominant source of military and economic power. He called for closer coordination among democratic nations on AI policy, safety standards, and supply-chain controls.

Context of Mythos Launch

The debate around Mythos follows months of friction between Anthropic and U.S. officials over AI safety and military applications. Earlier this year, the Trump administration moved to phase out Anthropic’s technology from federal agencies after the company maintained restrictions on mass surveillance and autonomous weapons. Anthropic later briefed members of the House Homeland Security Committee on Mythos and its national security implications. Pentagon tech chief Emil Michael also described the model as a "separate national security moment" because of its advanced cyber capabilities. The essay comes days after Anthropic launched Mythos 5, the latest version of its cybersecurity-focused AI model, alongside Claude Fable 5, its newest consumer-facing system.