CNaught launches an open source plugin that lets developers track real-time carbon emissions from AI-assisted coding, addressing a major transparency gap in AI’s environmental impact.
CNaught has launched Carbonlog, an open-source Claude Code plugin designed to track the carbon footprint of AI-assisted software development in real time. Positioned as the first developer tool to deliver per-session emissions visibility, Carbonlog enables developers to measure both energy consumption and CO₂ emissions for every coding interaction.
The open-source release makes complex academic estimation models accessible as a turnkey tool, allowing developers to quantify AI-related emissions without building their own frameworks. This approach aims to improve transparency, enable community validation, and establish an open infrastructure layer for measuring AI’s environmental cost.
The launch addresses a critical gap: ten of thirteen major AI companies do not disclose the environmental impact of their models, according to Stanford’s 2025 Foundation Model Transparency Index. Meanwhile, rising AI adoption is driving significant energy demand. The International Energy Agency projects data centre electricity consumption will reach 945 TWh by 2030, while Goldman Sachs estimates emissions could hit 215–220 million tonnes of CO₂.
Carbonlog operates as a Claude Code plugin, estimating emissions per API request and displaying cumulative impact in real time. It also generates detailed reports by model, project, and timeframe, translating data into relatable metrics such as car miles and household energy use. All data is stored locally by default, with optional anonymous benchmarking.
Built on research by Jegham et al. (2025), the tool uses first-principles energy estimation and real-time benchmarks. It also supports upcoming regulatory needs, including California SB 253, which mandates Scope 3 emissions reporting from 2027.
“We built Carbonlog because measurement has to come before management, and right now, almost nobody is measuring,” said Mark Chen, Co-founder and CEO, CNaught.
Currently in beta, Carbonlog is available now and installs in about 30 seconds, with plans to expand across more AI tools.
