With agentic coding the costs of tokens compound with each message / tool call and etc. Having to load in and update large files makes things slower and way more expensive.

Databricks actually just posted some of their own benchmarks on how harness alone impacts costs https://www.databricks.com/blog/benchmarking-coding-agents-d...

simple things like passing more file context, model having to explore the code base at start of each session, writing comments or markdown docs ends up increasing, running into test / build issues can 3-10x your costs.

PS: my code is still mostly TS and rust but I'm considering moving some of my annotations into .d.ts files and having them generated from runtime types (ala MonkeyType).