Long Horizon
Environments deliberately designed to take hours or days of agent effort: sprawling codebases, multi-stage projects, tasks with delayed and sparse rewards. Long-horizon coherence is the axis on which current frontier models improve fastest, and these environments are how that improvement gets measured and trained.
16 startups
| Name | Domains | Location | Team | Funding | Raising |
|---|---|---|---|---|---|
| AIChamp Custom enterprise-workflow RL environments with expert grading | Enterprise, Long Horizon, Custom Environments | San Francisco | 1-10 | - | - |
| Andon Labs Long-horizon autonomy benchmarks like Vending-Bench | Long Horizon, Alignment | San Francisco | 1-10 | Seed (Y Combinator) | - |
| Andromede Programmatic generation of long-horizon RL environments | Long Horizon | Lausanne | 1-10 | - | - |
| Anthromind Medical and long-horizon environments and expert data | Medical, Long Horizon, Data Labeling | San Francisco | 1-10 | - | - |
| ARIMLABS Security and long-horizon environments for agentic AI | Cybersecurity, Long Horizon | Warsaw | 11-25 | - | - |
| Collinear Enterprise simulation, judges, and long-horizon trajectory generation | Enterprise, Long Horizon, Machine Learning, Simulation | Mountain View, Sunnyvale | 11-25 | - | - |
| Diffuse Labs ML and long-horizon RL environments | Machine Learning, Long Horizon | Palo Alto, San Francisco | 1-10 | - | - |
| EdotEnv Long-horizon planning environments for frontier models | Long Horizon, Machine Learning | San Francisco | 1-10 | - | - |
| General Reasoning Open reasoning data and reward models from the ex-Meta AI reasoning lead | Finance, Long Horizon, Machine Learning | London, San Francisco | 1-10 | ~$10.9M (reported) | - |
| Good Start Labs Game-based RL environments and benchmarks | Games, Long Horizon | Brooklyn, New York, Toronto | 1-10 | ~$3.6M (reported) | - |
| HUD Evals and RL environments platform for computer-use agents | Computer Use, Coding, Long Horizon, Agents Infrastructure, Custom Environments | San Francisco, Singapore | 11-25 | $15M raised (YC W25, Exceptional Capital) | - |
| Huzzle Labs Long-horizon code, tool-use, and enterprise workflow environments | Long Horizon, Coding, Enterprise | London, Berlin, San Francisco | 26-50 | ~$6M (reported) | - |
| Originator Long-horizon computer-use environments | Computer Use, Coding, Long Horizon | London, Paris | 1-10 | - | - |
| pre.dev Software-planning platform offering coding and long-horizon RL environments | Coding, Long Horizon | Delaware | 1-10 | - | - |
| Proximal Long-horizon coding RL environments built from real codebases | Coding, Long Horizon | San Francisco, Bangalore | 26-50 | - | - |
| Tacit Labs Life-science and long-horizon environments for AI models | Science, Long Horizon | San Francisco | 1-10 | - | - |