[Internal Testing] Promote Gemini 3.1 Flash Lite to GA and support Gemini 3.5 Flash by sripasg · Pull Request #27705 · google-gemini/gemini-cli

sripasg · 2026-06-06T00:01:17Z

Summary

This commit merges and unifies three separate lines of changes onto the release branch:

Gemini 3.1 Flash Lite GA Promotion (PR 27071): Replaces retired preview models (e.g. gemini-3.1-flash-lite-preview / none) with the stable gemini-3.1-flash-lite GA model and updates the default auto-routing and policy chains to use it as the main lightweight fallback/utility tier.
Gemini 3.5 Flash Experiment Hook (PR 27570): Introduces experimental logic (GEMINI_3_5_FLASH_GA_LAUNCHED) and backend capability switches to transition users over to Gemini 3.5 Flash when experiment flag values are present.
Gemini 3.5 Flash GA Backend Support (PR 27645): Fully wires up dynamic model configuration aliases, default policies, and resolver mapping layers to respect backend definition limits and API-key-specific fallback paths for both Gemini 3.5 Flash and gemini-3-flash-preview.
Vertex ai model mapping fix (PR 27749): LOGIN_WITH_GOOGLE and COMPUTE_ADC auth types hit CCPA which routes gemini-3-flash to gemini-3.5-flash on their end, but they do not accept gemini-3.5-flash as the model ID. This updates calls to them as the exception rather than the rule, and sets the default 3.5 flash model to be gemini-3.5-flash and only changes it to gemini-3-flash when it should be hitting CCPA.

Details

1. Core Model Configurations & Resolutions (`packages/core/src/config/`)

models.ts
- Marked PREVIEW_GEMINI_FLASH_LITE_MODEL as deprecated ('none') and promoted DEFAULT_GEMINI_FLASH_LITE_MODEL ('gemini-3.1-flash-lite') to GA.
- Added DEFAULT_GEMINI_3_5_FLASH_MODEL ('gemini-3.5-flash') and SECONDARY_GEMINI_3_5_FLASH_MODEL ('gemini-3-flash').
- Updated resolveModel and resolveClassifierModel to dynamically route alias strings (auto, pro, flash) depending on user preview permissions and 3.5 Flash experiment access flags.
defaultModelConfigs.ts
- Structured new dynamic auto resolutions (auto-gemini-3, auto-gemini-2.5, flash) using conditional contexts matching useGemini3_5Flash and hasAccessToPreview.
- Configured distinct classifier routing lists for flash and pro tiers that resolve cleanly to gemini-3.5-flash or gemini-3-flash-preview based on user flags.
config.ts
- Added hasGemini35FlashGAAccess() to probe runtime experiments and configure default flash models (setFlashModels).
- Integrated getReleaseChannel() helper mapping back to the standard version channel.

2. Policy Chains & Fallback Mechanics (`packages/core/src/availability/`)

policyHelpers.ts
- Updated policy-slicing logic (resolvePolicyChain) to dynamically check for useGemini3_5Flash flags.
- Added family-based auto-routing fallbacks for Gemini 3 chains to wrap around cleanly when primary choices are exhausted.
policyCatalog.ts
- Updated getModelPolicyChain templates to conditionally load proModel overrides based on the 3.5 Flash GA launch settings.

3. Routing Strategies (`packages/core/src/routing/strategies/`)

Updated classifier strategies (approvalModeStrategy, classifierStrategy, gemmaClassifierStrategy, numericalClassifierStrategy, overrideStrategy) to pass the useGemini3_5Flash access context into all model resolution calls, ensuring aligned and predictable routing behavior across the agent workflow.

4. Frontend & Terminal UI (`packages/cli/src/ui/components/`)

ModelDialog.tsx
- Updated the manual model selection UI to correctly sort and render the new GA models (gemini-3.1-flash-lite, gemini-3.5-flash).
- Filtered out retired/retired-preview options (like none) from the selectable list.
Updated related UI layouts, snapshot tests, and markdown helper guides to reflect the consolidated model list.

How to Validate

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Pre-Merge Checklist

github-actions · 2026-06-06T00:01:27Z

📊 PR Size: size/XL

Lines changed: 3321
Additions: +2676
Deletions: -645
Files changed: 78

gemini-code-assist · 2026-06-06T00:02:35Z

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 streamlines the model management lifecycle by promoting Gemini 3.1 Flash Lite to GA and introducing support for Gemini 3.5 Flash. The changes include a significant refactor of the core configuration, policy resolution, and routing strategies to support dynamic model switching based on experiment flags and user permissions. Additionally, legacy preview models have been cleaned up across the codebase to ensure a consistent user experience in the CLI and terminal UI.

Highlights

Gemini 3.1 Flash Lite GA Promotion: Promoted Gemini 3.1 Flash Lite to General Availability and updated default routing to utilize it as the primary lightweight model.
Gemini 3.5 Flash Integration: Added backend support and experimental hooks for Gemini 3.5 Flash, allowing dynamic model resolution based on user experiment flags.
Model Configuration Refactoring: Unified model resolution logic and policy chains to dynamically handle alias routing and fallback paths for the new model tiers.
Cleanup and UI Updates: Removed retired preview models from the CLI selection UI and updated documentation to reflect the new GA model landscape.

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github-actions · 2026-06-06T00:04:33Z

Size Change: +5.43 kB (+0.02%)

Total Size: 34.1 MB

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gemini-code-assist

Code Review

This pull request adds support for the Gemini 3.5 Flash GA model, updates model routing and resolution logic, and retires the Gemini 3.1 Flash Lite preview model. It also updates configuration documentation, CLI UI components, and shell tool background execution cleanup. The review feedback highlights a parsing bug in llm-judge.ts where lowercase LLM responses are incorrectly stripped, and warns against mutating global module-level variables to set flash models, which introduces severe race conditions in concurrent environments.

_{Note: Security Review did not run due to the size of the PR.}

github-actions · 2026-06-10T04:24:04Z

✅ 63 tests passed successfully on gemini-3-flash-preview.

🧠 Model Steering Guidance

This PR modifies files that affect the model's behavior (prompts, tools, or instructions).

🚀 Maintainer Reminder: Please ensure that these changes do not regress results on benchmark evals before merging.

This is an automated guidance message triggered by steering logic signatures.

Update default flash lite tool model

a57f33a

sripasg requested review from a team as code owners June 6, 2026 00:01

github-actions Bot added the size/xl An extra large PR label Jun 6, 2026

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Comment thread evals/llm-judge.ts Outdated

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Comment thread packages/core/src/config/models.ts Outdated

gemini-cli Bot added the status/need-issue Pull requests that need to have an associated issue. label Jun 6, 2026

This was referenced Jun 6, 2026

📊 AI CLI 工具社区动态日报 2026-06-06 zx0828/big_model_radar#88

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📊 AI CLI 工具社区动态日报 2026-06-06 litang9/big_model_radar#21

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sripasg force-pushed the internal_testing_release_branch_35_branch branch from 3f8b76b to 3b82818 Compare June 9, 2026 16:59

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📊 AI CLI 工具社区动态日报 2026-06-10 hehongtao88/big_model_radar#1

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feat: promote Gemini 3.1 Flash Lite to GA and support Gemini 3.5 Flash

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[Internal Testing] Promote Gemini 3.1 Flash Lite to GA and support Gemini 3.5 Flash#27705

[Internal Testing] Promote Gemini 3.1 Flash Lite to GA and support Gemini 3.5 Flash#27705
sripasg wants to merge 2 commits into
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Summary

Details

1. Core Model Configurations & Resolutions (packages/core/src/config/)

2. Policy Chains & Fallback Mechanics (packages/core/src/availability/)

3. Routing Strategies (packages/core/src/routing/strategies/)

4. Frontend & Terminal UI (packages/cli/src/ui/components/)

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sripasg commented Jun 6, 2026 •

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1. Core Model Configurations & Resolutions (`packages/core/src/config/`)

2. Policy Chains & Fallback Mechanics (`packages/core/src/availability/`)

3. Routing Strategies (`packages/core/src/routing/strategies/`)

4. Frontend & Terminal UI (`packages/cli/src/ui/components/`)

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