Cosine

Cosine is a London AI lab that trains its own coding models, called Lumen, and runs a coding agent on top of them. The agent works in a terminal (Cosine CLI), in a desktop app and in Cosine Cloud, where agents run tasks in parallel in isolated sandboxes and open pull requests for review. Alistair Pullen (CEO) and Yang Li (COO) founded Cosine in 2022, and it went through Y Combinator in Winter 2023. Press coverage listed on its newsroom in August 2026 describes a company of about 30 people that had raised $15 million.

Lumen has three tiers. Lumen Scout, post-trained from Devstral 123B, handles low-cost utility work such as codebase mapping and retrieval. Lumen Outpost, post-trained from Kimi K2.6, is the main coding model, tuned for maintainable code with fewer unnecessary changes and for less common languages such as COBOL, ABAP, Fortran and Verilog. Cosine reports that Outpost scored 53.9% on Niche-Bench, its own benchmark, against 48.3% for Kimi K2.6 and 47.4% for GPT-5.5. Lumen Sovereign is planned, not released: it is being trained on the Isambard-AI supercomputer with compute from the UK Government Sovereign AI programme, with a coalition that includes BAE Systems, BT, HSBC, Lloyds Banking Group, NatWest and Thales UK helping to define its requirements, and a target of late 2026.

The agent is model-agnostic. Besides Lumen it offers GPT, Claude, Gemini, Kimi, GLM and other models, each priced as a credit multiplier, and the CLI can run on an existing ChatGPT or Claude subscription instead of Cosine credits. Modes include Plan (read-only), Auto and Swarm, where an orchestrator splits a task across parallel subagents. The CLI installs on macOS, Windows and Linux, connects to external tools through MCP and checkpoints every agent turn as a git commit. Cloud projects connect to GitHub through a GitHub App, and the changelog records GitLab, Bitbucket and Azure DevOps support. Native Slack, Jira and Linear integrations were removed from the Cloud dashboard in September 2026, so those tools now connect through MCP. Cosine also sells Red Team, an AI penetration-testing service, as a separate product.

Deployment runs from the public Cosine Cloud to a managed single-tenant cloud or a fully air-gapped installation inside the customer network, using Lumen, open-weight or customer-approved models. Published pricing is per team, not per seat: Starter $19 a month with 4M credits, Team $199 with 47M credits and Enterprise $999 with 240M credits, with add-on credits at $6.50, $5.00 and $4.50 per 1M. Paid teams can add members at no extra cost. Private and air-gapped deployments are priced through sales. The billing documentation lists a different set of plans (Starter, Builder, Team, Scale, Professional) from the pricing page, so buyers should confirm current plan names at checkout.

Teams comparing hosted autonomous engineers should also look at Devin. Teams that want an open-source agent they can self-host and modify should consider OpenHands. Developers who mainly want an agent inside their editor should consider Cursor. Independent review evidence for Cosine is thin: 6 reviews on Product Hunt and none on G2, so most performance evidence comes from Cosine itself.

Current state Q4 2026: Lumen Outpost launched in May 2026. Cosine formed the Lumen Sovereign coalition in June 2026, announced partnerships with Mimic (cybersecurity, August 2026) and Shift (financial operational resilience, October 2026), and published findings from its public request for input on Lumen Sovereign in October 2026. Lumen Sovereign is still in training.