Resolution criteria

• Resolves to the company that is officially identified as having trained and owning the base weights of the large language model referred to publicly as “Sonic” as exposed in Cursor in August 2025. Acceptable evidence: (a) an official announcement or documentation by the company, (b) an official Cursor post naming the provider/model, or (c) reporting by a top-tier outlet quoting a company spokesperson. Examples of sources to check: OpenAI News, xAI News, Google DeepMind Blog, Anthropic News, 📰 Meta AI Blog, Microsoft AI Blog, and the Cursor forum/blog. (openai.com, x.ai, deepmind.google, anthropic.com, ai.meta.com, blogs.microsoft.com, forum.cursor.com)

• If multiple entities are involved (e.g., a fine‑tune or hosted variant), credit goes to the organization that trained the underlying base model weights named in official materials. If two companies co‑develop and both claim training, resolve to the one credited with training the model in the official announcement.

• If no credible attribution is public by December 31, 2025, resolve to “Other” (automatically present when anyone can add answers). (forum.cursor.com)

Background

• Cursor staff state that “sonic” is a new ghost model from an external AI partner (not built by Cursor) with a 256k context window, and that the provider/model will be revealed. (forum.cursor.com)

• Cursor says it uses external models from OpenAI, Anthropic, Google, and xAI; it also recently added GPT‑5 access. This makes those four especially plausible. (cursor.com)

• xAI’s Grok 4 API advertises a 256,000‑token context window, matching the “Sonic” context size mentioned by Cursor users. This is a clue, not proof. (x.ai, forum.cursor.com)

Considerations

• “Sonic” is a codename/alias surfaced in Cursor; the provider’s branded name may differ (e.g., if “Sonic” maps to a known flagship like Grok, GPT, Claude, or Gemini). Resolution credits the base‑model developer, not an integrator/host. (forum.cursor.com)

• Meta and Microsoft are possible but were not listed by Cursor among its typical external providers as of June 2025; still resolve to them if official attribution says so. (cursor.com)

• If multiple unrelated “Sonic” models emerge, this market tracks the one available in Cursor beginning around August 20, 2025. (forum.cursor.com)