feat: enable prompt caching for gemini-2.5-flash-preview-05-20

[shariqriazz]

Closes: #3901

Description

This PR enables supportsPromptCache for the gemini-2.5-flash-preview-05-20:thinking and gemini-2.5-flash-preview-05-20 models within both the vertexModels and geminiModels configurations in src/shared/api.ts. This change allows these specific Gemini models to utilize prompt caching, which can improve performance and reduce costs for repetitive prompts.

Test Procedure

This change is a configuration update for model capabilities.

• No new unit tests were added as this is a direct configuration change.
• Existing API integration tests for Gemini models should continue to pass.
• Manual verification would involve observing prompt caching behavior if a specific testing environment for it is available.

Type of Change

• 🐛 Bug Fix: Non-breaking change that fixes an issue.
• ✨ New Feature: Non-breaking change that adds functionality.
• 💥 Breaking Change: Fix or feature that would cause existing functionality to not work as expected.
• ♻️ Refactor: Code change that neither fixes a bug nor adds a feature.
• 💅 Style: Changes that do not affect the meaning of the code (white-space, formatting, etc.).
• 📚 Documentation: Updates to documentation files.
• ⚙️ Build/CI: Changes to the build process or CI configuration.
• 🧹 Chore: Other changes that don't modify src or test files.

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Code Quality:
  • My code adheres to the project's style guidelines.
  • There are no new linting errors or warnings (npm run lint).
  • All debug code (e.g., console.log) has been removed.
• Testing:
  • New and/or updated tests have been added to cover my changes. (N/A for this configuration change)
  • All tests pass locally (npm test). (Assuming existing tests pass)
  • The application builds successfully with my changes. (Assuming successful build)
• Branch Hygiene: My branch is up-to-date (rebased) with the main branch.
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Changeset: A changeset has been created using npm run changeset if this PR includes user-facing changes or dependency updates.
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Screenshots / Videos

N/A

Documentation Updates

• No documentation updates are required.
• Yes, documentation updates are required. (This change is an internal model configuration and likely does not require user-facing documentation updates.)

Additional Notes

None.

Get in Touch

shariqriaz

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Important

Enables prompt caching for gemini-2.5-flash-preview-05-20 models in src/shared/api.ts to improve performance and reduce costs.

• Configuration Update:
  • Enables supportsPromptCache for gemini-2.5-flash-preview-05-20:thinking and gemini-2.5-flash-preview-05-20 models in src/shared/api.ts.
  • Affects vertexModels and geminiModels configurations.
• Testing:
  • No new unit tests added; existing tests should pass.
  • Manual verification of prompt caching behavior if environment available.

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[ellipsis-dev]

Enabled prompt caching for Gemini model gemini-2.5-flash-preview-05-20. Consider whether cache pricing details (e.g. cacheReadsPrice/cacheWritesPrice) are needed for this model.

[shariqriazz]

@mrubens do we need to add cache pricing in vertex models also? i don't see it in pro-preview either in vertex so i just added for geminimodels at the moment

also do we keep pro-exp which doesnt work anymore and 04-17 flasg which is now replaced by 05-20 flash?