Cosine

Cosine is the AI coding platform built around Lumen, its family of production-first coding models designed for real engineering work: maintainable software, long-lived systems, and the complex codebases most models struggle to handle. Founded in 2022 by Alistair Pullen and Yang Li (who previously scaled Mobike to 220 million users), Cosine is a Y Combinator graduate that has raised $8 million from Lakestar, SOMA Capital, and Gaingels. The UK government selected Cosine as one of the first partners in its newly launched 500 million pound Sovereign AI programme, and the company is already deployed across UK defence primes and critical national infrastructure operators including organisations involved in the UK nuclear deterrent programmes. Lumen models are trained to eliminate slop: duplication, dead code, and unnecessary complexity. They are optimized for minimal diffs that match codebase style and stay maintainable over time. Lumen is post-trained for enterprise and niche languages including C, R, Matlab, Fortran, Verilog, and Rust, using an 8-step data pipeline that turns real production code into verifiable training trajectories. The current model lineup includes Lumen Scout (lightweight), Lumen Outpost (frontier), and Lumen Sovereign (UK sovereign deployment). On Niche-Bench, Lumen Outpost scored 59.3%, outperforming GPT-5.4 (42.4%), Gemini 3.1 Pro (44.9%), GPT-5.5 (47.4%), and Kimi K2.6 (48.3%). Integration depth spans multiple product surfaces: native desktop apps for Mac, Windows, and Linux, a CLI distributed via Homebrew, and cloud-based execution. The platform integrates with Git, GitHub, GitLab, Slack, Jira, and Linear. MCP support enables external tool connections. Cosine Swarm enables parallel AI agents for long-horizon, complex software tasks. A separate Red Team product provides AI-driven continuous penetration testing. Enterprise deployment options include public cloud, managed single-tenant cloud, and fully air-gapped configurations with custom model weights deployed to customer GPUs, addressing environments where sending code to foreign-managed servers is legally prohibited. Pricing is fully public across three tiers. Hobby at $20/seat/month provides 5M Cosine Credits per seat per month with credit top-ups at $20 for 5M additional credits and full access to all platform features. Professional at $200/seat/month provides 60M Cosine Credits per seat per month. Enterprise is custom-priced with cloud, VPC, or fully air-gapped deployment, custom model weights, zero data egress, and dedicated support. A training layer for turning private engineering knowledge into specialized models is listed as coming soon. Cosine is not the right fit for teams needing the broadest autonomous agent capabilities at the lowest price point. Cursor at $20/month and Claude Code at $20/month both provide broader feature sets for general-purpose coding. The Professional tier at $200/seat/month is significantly more expensive than mainstream alternatives, with the premium justified by production code quality, niche language support, and sovereign deployment capabilities. G2 reviews are not yet available, limiting independent peer sentiment data for procurement teams that rely on review platforms. Current state Q2 2026: Cosine was selected for the UK government's 500 million pound Sovereign AI programme. The Lumen model family expanded to three tiers: Scout, Outpost, and Sovereign. Cosine Swarm launched for parallel agent execution on complex tasks. Red Team launched as a separate product for AI-driven continuous penetration testing. Lumen Outpost leads Niche-Bench at 59.3%. The company has 32 employees and operates from London with deployment across UK defence and critical national infrastructure.