The AI coding fight just moved from the model to the harness

The AI coding market is shifting from model competition to the 'harness' layer, the software that routes coding tasks to models, as enterprises push back on price hikes from tools like Cursor. Cursor, which SpaceX agreed to buy for $60bn, faced renewal bills up to five times higher for firms like Sanofi and Druva, prompting some to switch to Anthropic's Claude Code. However, open-source harnesses like OpenCode are cutting costs by 25% to 97%, leading startups like Sapiom and Codestrap to argue that value now lies in the routing layer, not the model itself.

The most expensive part of AI coding is no longer the model. It is the software wrapped around it, and enterprises have started to notice. The immediate fight is over price. Cursor, the AI coding tool SpaceX has agreed to buy for $60bn https://thenextweb.com/news/spacex-cursor-acquisition-official-60-billion , moved most customers to usage-based billing last year. The renewal bills are now landing hard, The Information reported https://www.theinformation.com/newsletters/applied-ai/cursor-customers-fight-price-hikes-contract-talks . The renewal shock One IT consulting firm paid Cursor about $200,000 for 800 licences in the year to May. At renewal, Cursor asked for roughly $1.5m for the same usage. The firm “played hard ball” and got it down to $250,000. Others tell similar stories. The biopharma group Sanofi and the security vendor Druva both faced renewals about five times higher than last year. “I may not renew with Cursor,” Sanofi’s chief digital officer Emmanuel Frenehard told The Information. “I get a better deal with Claude Code.” The flight to Claude Code That is the near-term winner. Anthropic’s Claude Code is tuned for its own models, and firms are moving spend there. The same IT consultancy expects its Anthropic bill to jump to at least $10m this year. In 2025 it was almost nothing. It is the mirror image of Cursor’s problem. Cursor discounts where it wants scale https://thenextweb.com/news/cursor-start-india-pricing-own-models-spacex , and charges hard where customers are locked in. It has less pricing power than Anthropic. It is not all one way, though. Data from the routing firm Weave shows Cursor bills actually rose less than Claude Code bills over the past six months. Cursor now offers a router, too, that sends simple tasks to cheaper models. There is room for more than one winner. Even Claude Code is being bypassed Here is the part that should worry Anthropic too. The layer that matters now is the “harness,” the software that lets a model actually write and edit code. Claude Code uses Anthropic’s own proprietary harness. Open-source harnesses do the same job, and they plug into routers that shunt simpler work to cheaper open-weight or small models https://thenextweb.com/news/poolside-laguna-s-2-1-open-weight-coding-model . The savings are not small. Sapiom, a startup Anthropic itself has backed, swapped in the open-source OpenCode harness and expects to cut its AI spending by 25%. Codestrap, a coding consultancy, says customer costs fell 97% after it built its own platform. That platform routes most tasks to small Google and OpenAI models. “It’s not about the model anymore,” Sapiom’s Ilan Zerbib told The Information. “It’s about the harness around the model.” Codestrap’s Connor Deeks put it more bluntly: “All the value is accruing to the harness. It has nothing to do with the model.” Why it matters This is the agentic-cost squeeze https://thenextweb.com/news/token-prices-fell-98-enterprise-ai-bills-tripled-now-the-industry-wants-a-standards-body-to-explain-why reaching the tool layer. Per-token prices keep falling, but autonomous agents burn so many tokens that enterprise bills keep climbing https://thenextweb.com/news/microsoft-claude-code-retreat-ai-cost . Cursor is feeling it first. If the real value sits in the routing layer, the same logic is coming for the premium tools built on top, Claude Code included. Anthropic reigns in coding today. Its customers are starting to ask how much of that lead is the model, and how much is a harness anyone can rebuild. Get the TNW newsletter Get the most important tech news in your inbox each week.