Chalk Wars: AI Rivals Clash on San Francisco Sidewalks

Anthropic and OpenAI battle over Pentagon deals through guerrilla chalk art

Published on Mar. 2, 2026

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The rivalry between two San Francisco-based AI companies, Anthropic and OpenAI, has spilled onto the city's sidewalks. Unknown activists have taken to chalking messages outside the firms' headquarters, praising Anthropic for refusing a Pentagon deal that would allow expanded military use of its technology, while lambasting OpenAI for striking its own agreement with the Department of Defense.

Why it matters

The chalk war highlights the growing tensions in the AI industry over the use of advanced technologies for military and surveillance purposes. As leading AI firms navigate these ethical dilemmas, their decisions have real-world implications for civil liberties and the public's trust in the technology sector.

The details

Chalk messages first appeared outside Anthropic's downtown headquarters on Friday morning, defending the company's 'courage' in its fight against the Pentagon's demands. When it became clear that Anthropic had lost its government deal, the chalk warriors shifted their focus to OpenAI's headquarters in Mission Bay, where they left messages questioning the company's new contract with the Department of Defense and urging it to 'do the right thing' and 'not help the government spy on Americans'.

  • On Friday morning, chalk messages appeared outside Anthropic's headquarters.
  • By Friday evening, chalk messages had appeared outside OpenAI's headquarters.

The players

Anthropic

A San Francisco-based artificial intelligence company that refused to loosen the terms of its contract with the Pentagon, which sought expanded use of its AI technology for military purposes.

OpenAI

A San Francisco-based AI company that struck a deal with the Department of Defense, despite initially appearing to side with Anthropic in the standoff.

Pete Hegseth

The U.S. Defense Secretary who issued an ultimatum for Anthropic to loosen the terms of its contract with the Pentagon.

Donald Trump

The former U.S. President who ordered federal agencies to stop using Anthropic technology and warned of 'major' consequences.

Sam Altman

The CEO of OpenAI, who announced that his company had reached an agreement with the Department of Defense to deploy its AI models in their classified network.

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What they’re saying

“Two of our most important safety principles are prohibitions on domestic mass surveillance and human responsibility for the use of force, including for autonomous weapon systems.”

— Sam Altman, CEO, OpenAI (Twitter)

“Show the contract.”

— Unknown (Chalk message)

“Take a stand for civil liberty.”

— Unknown (Chalk message)

What’s next

The Department of Defense has not yet commented on the specifics of its agreements with Anthropic and OpenAI, leaving many questions unanswered about the use of the companies' AI technologies for military and surveillance purposes.

The takeaway

The chalk war on San Francisco's sidewalks reflects the broader tensions in the tech industry over the ethical use of AI. As leading firms navigate these complex issues, their decisions will continue to have significant implications for civil liberties and public trust in the technology sector.