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 program. The company is already deployed across UK defense primes and critical national infrastructure operators, including organizations involved in the UK nuclear deterrent programs. 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 with flat monthly rates rather than per-seat charges. Starter at $19/month provides 4M Cosine Credits per month with add-on credits at $6.50 per 1M, designed for individuals or teams just starting out. Team at $199/month provides 47M credits per month with add-on credits at $5.00 per 1M, for teams beginning to scale. Enterprise starts at $999/month with 240M credits per month and add-on credits at $4.50 per 1M, for organizations needing maximum resources. Custom pricing is available for enterprise teams needing tailored solutions with cloud, VPC, or fully air-gapped deployment, custom model weights, zero data egress, and dedicated support. Cosine is not the right fit for teams needing the broadest autonomous agent capabilities at the lowest price point. Cursor ($16/mo billed annually) and Claude Code ($17/mo billed annually) both provide broader feature sets for general-purpose coding. The Team tier at $199/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 Q3 2026: Cosine assembled a coalition of leading UK defense, infrastructure, financial, healthcare, and technology leaders for Sovereign AI. 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 defense and critical national infrastructure.