Promt Caching for Gemini 2.5 Flash

[c0va23]

App Version

3.14.3

API Provider

OpenRouter

Model Used

Gemini 2.5 Flash

Actual vs. Expected Behavior

Looks like Gemini 2.5 Flash on the OpenRouter provider is missing the prompt caching feature. The thinking version of the model also misses this feature.

The official OpenRouter X says that almost all Gemini Models support prompt caching (including Gemini 2.5 Flash).

Detailed Steps to Reproduce

1. Select OpenRouter provider
2. Select google/gemini-2.5-flash-preview model
3. After we see "Does not support prompt caching"
4. And we don't see "Enable prompt caching" checkbox

Relevant API Request Output

Additional Context

Gemini 2.5 Pro and Gemini 2.0 Flash models support the prompt caching feature.

[dosubot]

Hello @c0va23! I'm Dosu, a bot here to help you solve bugs, answer questions, and assist you in becoming a contributor. While you wait for a human maintainer, feel free to let me know how I can help!

The Gemini 2.5 Flash model does not currently support prompt caching, whereas the Gemini 2.5 Pro model does support prompt caching as part of the Gemini 2.5 Pro Preview. Prompt caching for Gemini 2.5 Flash Preview is mentioned as coming soon, but it is not yet available. Additionally, for the Gemini 2.5 models, prompt caching is not enabled by default and must be manually activated by checking the "Enable Prompt Caching" box in the provider settings. This manual activation is necessary due to potential response delays with Google's caching mechanism ^[1][2].

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[hannesrudolph]

@c0va23 what the bot said. Sorry. https://ai.google.dev/gemini-api/docs/models#gemini-2.5-flash-preview

once it is out we will work to support it ASAP.

[c0va23]

@hannesrudolph, but this page say that context caching is supported.

[hannesrudolph]

Roo Code does not yet support prompt caching with Vertex but it is going to be implemented with our next release (hopefully today) #2996