A new open-source tool called Frugal Tokens helps developers track and analyze costs across coding agent sessions. Built by dpclark4, the project originated from curiosity about session expenses and cache miss impact. The tool visualizes overall usage, estimated working time, overlapping sessions, and spending breakdowns across models. It includes session-level metrics with percentile data and a detailed session explorer showing individual model calls, tool inputs, and outputs. Users can jump directly to cache miss locations and compare costs using different model pricing, including Anthropic's 5m vs 1h caching options. The project aims to identify patterns that increase workflow costs, such as long sessions or high context usage. It requires Deno to run but launches with a single command. A scrubbed demo dataset is available to preview functionality.

The tool currently supports cost comparisons, session exploration, and usage analytics. Future plans include collecting broader data to uncover cost-driving behaviors in AI-assisted development workflows.

Available on GitHub, the project invites feedback and contributions from the developer community.