Developer reports month-long GLM 5.3 Flash coding experiment, costs and hurdles
A developer detailed a month-long coding experiment using GLM 5.3 Flash, noting that the first half stayed within budget at $68, about 4kWh of energy, and 365 grams of carbon emissions. The second half saw 1 billion tokens diverted to other models, and a 'vibe coding' prototype with the wrong model consumed 450 million tokens, $150, and 5kWh almost overnight, highlighting the importance of careful model selection.
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Zooming in on the models split specifically: The goal was to spend the whole month on GLM 5.3 Flash pictured in teal. Here’s what went well: * Successfully spent the first half of the month on just that model. * That model’s usage was well within our budget ($68, about 4kWh of energy use / 365 grams of carbon emissions). The second half of the month didn’t go so well, with 1B tokens going to other models. ## Unexpected hurdles ### The cost of vibe coding We’re pretty transparent that our experimental Wagtail MCP server is a vibe-coded prototype. Vibe coding isn’t quite what we normally aspire to, but for a prototype it’s spot on. Unfortunately there are still consequences to it. I chose the 'wrong' model for the prototype, and we spent 450M tokens / $150 / 5kWh of energy use almost overnight. The MCP server itself works well and we now have a great demo of the capabilities, so it’s not for nothing: Video 3 Nonetheless, it’s a good reminder to be careful with model selection and with ag