OpenRouter Claude 3.7: Prompt caching via OpenRouter does not appear to work.

[cfdude]

Which version of the app are you using?

3.7.4

Which API Provider are you using?

OpenRouter

Which Model are you using?

Claude Sonnet 3.7

What happened?

Reported from user on Discord: https://discord.com/channels/1332146336664915968/1343919743022661643

When choosing OpenRouter, both the :beta and the regular version of Claude Sonnet do not show prompt caching in the UI. In addition, the cost of the prompts do seem high enough that prompt caching doesn't seem likely to be happening.

This happens in both Claude 3.5 and Claude 3.7. To my recollection, this has always happened - I just didn't realize until now this is potentially undesirable behavior. I just saw that openrouter supports caching so raising this in hindsight.

Steps to reproduce

Relevant API REQUEST output

Additional context

The user did report that prompt caching is working in Cline, so perhaps we need to pull that work that has already been done?

[cfdude]

The user that reported this is also wondering if we can make it possible to support prompt caching with Gemini since 2.0 Pro is coming out soon. Is that a possibility for us?