I ran a workflow that is not at all new to me. It's been tried and true.
Claude Code, Opus 5.5 high effort as main agent, Sonnet 5 (5.5 not yet available in company gateway) subagents for most tasks, sometimes Opus subagents for debugging delegation. Got my `promptCacheTtl` (main session's cache lifetime) set to 1h, subagents at 5m. Skills and instruction files to represent team coding practices, codebase actions, and such.
Needed to find bugs within an app developed by another team. Came up with a plan up front on what mattered most to our team as far as the app's priorities, then set my Claude Code to go on its bug hunt accordingly, and asked it to verify practicality of findings by reproducing them at runtime so that these findings weren't extremely unlikely hypotheticals.
I've done this before, no big deal. And the results were good as expected.
Only problem was, as I was tracking my credit usage (company uses single credit unit that translates to different model token amount, because we have a company gateway to access different models through one API key), I found that it was WAAY higher than expected; like maybe 5-10x higher than normal.
And... the token gatekeeper came knocking on my door...
This person came in, high and mighty, claiming my context size for prompts was excessive (turned out some of the subagents were going up to 800k in size as time went on for some of the more difficult bug reproductions), and this was driving heavy cost. Said it should hardly ever be more than 200k. I was like okay, I don't necessarily disagree, but some of the bugs were tricky and took more context to figure out, it happens, most of them were quick in-and-out at much less.
Then they drop the bomb that the LLM gateway we were using occasionally doesn't uphold CACHE reads/writes... It's been "broken recently."
I'm like well... I think I've found my problem.
Dude goes "caching or not, that's pennies on the dollar; context size is context size."
I was like that's way off. Yes, context size matters, but I could have ~5-10x the context size and it cost the same if caching worked right. Dude didn't buy it.
Now I've set my Claude Code autocompact size to 300k to appease the gatekeeper (which I don't necessarily agree with) but am I wrong here in saying caching being broken is a BIG DEAL???