Hi, I built this because I kept wondering "how much did that conversation
actually cost me" when using Claude.ai / ChatGPT in the browser (not the API).
Token Watcher intercepts the streaming responses client-side to read the
input/output/cache token counts and computes cost against current Anthropic/
OpenAI pricing — no API key, nothing leaves your browser.
It also tracks MCP (Model Context Protocol) call health — total calls and
error rate — which I haven't seen any other tool surface for the Claude.ai
web UI specifically.
Free tier: 7-day history, real-time cost + model breakdown, MCP monitoring.
Pro ($9 one-time): 30-day history + CSV export.
Happy to answer questions about how the token interception works or take
feedback on what else would be useful to track.
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