feat(core): fallback to 2.5 models with no access for toolcalls

[sehoon38]

Summary

This PR adds an optional hasAccessToPreview parameter to the resolveModel function in @google/gemini-cli-core. When this flag is set to false, any resolved preview model is automatically downgraded to its stable equivalent (e.g., gemini-3-pro-preview -> gemini-2.5-pro).

Details

• Modified resolveModel in packages/core/src/config/models.ts to accept hasAccessToPreview: boolean = true.
• Implemented downgrade logic for both pro and flash preview models.
• Updated policyHelpers.ts to pass the access flag from the configuration.
• Fixed a React hook dependency warning in useGeminiStream.ts that was blocking preflight.
• Updated cli-help-agent.ts to use a concrete preview model directly.

Related Issues

Fixes https://github.com/google-gemini/maintainers-gemini-cli/issues/1284

How to Validate

1. Run unit tests: npm test -w @google/gemini-cli-core -- src/config/models.test.ts
2. Verify that resolveModel with hasAccessToPreview: false returns non-preview models even when a preview model or alias is requested.

Pre-Merge Checklist

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the model resolution mechanism within the "@google/gemini-cli-core" package by introducing a new parameter to control access to preview models. This ensures that users without explicit access to preview models are automatically provided with stable alternatives, improving reliability and preventing unintended usage. Additionally, it includes a minor dependency fix in a React hook and updates an agent's model reference.

Highlights

• Model Resolution Logic: Introduced a new "hasAccessToPreview" parameter to the "resolveModel" function, allowing for conditional downgrading of preview models to their stable equivalents if access is denied.
• Preview Model Downgrade: Implemented logic within "resolveModel" to automatically downgrade requested preview models (e.g., "gemini-3-pro-preview") to their stable versions (e.g., "gemini-2.5-pro") when "hasAccessToPreview" is "false".
• Configuration Integration: Updated "policyHelpers.ts" to retrieve and pass the "hasAccessToPreview" flag from the configuration to the "resolveModel" function, ensuring consistent model resolution based on user access.
• Dependency Fix: Resolved a React hook dependency warning in "useGeminiStream.ts" by removing an unnecessary "config" dependency.
• Agent Model Update: Modified "cli-help-agent.ts" to directly use "PREVIEW_GEMINI_FLASH_MODEL" instead of an alias, aligning with the new model resolution strategy.

Changelog

• packages/cli/src/ui/hooks/useGeminiStream.ts
  • Removed "config" from the dependency array of "useGeminiStream" to resolve a React hook warning.
• packages/core/src/agents/cli-help-agent.ts
  • Updated the import for the Flash model from "GEMINI_MODEL_ALIAS_FLASH" to "PREVIEW_GEMINI_FLASH_MODEL".
  • Changed the "modelConfig" to use "PREVIEW_GEMINI_FLASH_MODEL" directly.
• packages/core/src/availability/policyHelpers.ts
  • Added "hasAccessToPreview" parameter to the "resolveModel" function call.
  • Moved the "hasAccessToPreview" variable declaration to before the "resolveModel" call.
  • Changed the return statement for proactive downgrade to an assignment to "chain".
• packages/core/src/config/models.test.ts
  • Added a new test suite for "hasAccessToPreview" logic, including tests for downgrading preview models to default stable models when access is false.
• packages/core/src/config/models.ts
  • Added "hasAccessToPreview: boolean = true" as a new parameter to the "resolveModel" function.
  • Refactored the "resolveModel" function to store the initial resolved model in a "resolved" variable.
  • Implemented conditional logic to check "hasAccessToPreview" and "isPreviewModel(resolved)", downgrading flash-lite, flash, and other preview models to their stable equivalents if access is false.

Activity

• Unit tests were run for "src/config/models.test.ts".
• Validation was performed on MacOS using "npm run".
• New tests were added for the model resolution logic.

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[gemini-code-assist]

Code Review

This pull request introduces a hasAccessToPreview parameter to the resolveModel function to automatically downgrade preview models to their stable counterparts when a user lacks access. The changes are well-implemented across the affected files, including updates to policy helpers and tests. I've identified one area for improvement in packages/core/src/config/models.ts where the model downgrade logic could be made more robust to prevent potential issues with future model naming conventions. Overall, this is a solid feature addition that improves model resolution logic.

[gemini-code-assist]

Code Review

This pull request introduces a mechanism to gracefully downgrade preview models to their stable equivalents for users without preview access by adding a hasAccessToPreview flag to the resolveModel function. However, the implementation is incomplete. Critical functions like resolveClassifierModel do not respect the new access control flag, leading to widespread bypasses of the intended security policy. Furthermore, the model downgrade logic in models.ts should be made more robust, explicit, and less reliant on string matching to enhance future maintainability.

[github-actions]

Size Change: +763 B (0%)

Total Size: 26 MB

ℹ️ View Unchanged

Filename	Size	Change
./bundle/gemini.js	25.5 MB	+763 B (0%)
./bundle/node_modules/@google/gemini-cli-devtools/dist/client/main.js	221 kB	0 B
./bundle/node_modules/@google/gemini-cli-devtools/dist/src/_client-assets.js	227 kB	0 B
./bundle/node_modules/@google/gemini-cli-devtools/dist/src/index.js	11.5 kB	0 B
./bundle/node_modules/@google/gemini-cli-devtools/dist/src/types.js	132 B	0 B
./bundle/sandbox-macos-permissive-open.sb	890 B	0 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB	0 B
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB	0 B
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB	0 B
./bundle/sandbox-macos-strict-open.sb	4.82 kB	0 B
./bundle/sandbox-macos-strict-proxied.sb	5.02 kB	0 B

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