feat(gemini): support mid-session model change (#379)

web/src/components/AssistantChat/HappyComposer.tsx

@@ -20,7 +20,7 @@ import { useActiveSuggestions } from '@/hooks/useActiveSuggestions'
 import { applySuggestion } from '@/utils/applySuggestion'
 import { usePlatform } from '@/hooks/usePlatform'
 import { usePWAInstall } from '@/hooks/usePWAInstall'
-import { isClaudeFlavor } from '@/lib/agentFlavorUtils'
+import { isClaudeFlavor, supportsModelChange } from '@/lib/agentFlavorUtils'
 import { markSkillUsed } from '@/lib/recent-skills'
 import { FloatingOverlay } from '@/components/ChatInput/FloatingOverlay'
 import { Autocomplete } from '@/components/ChatInput/Autocomplete'
@@ -28,7 +28,7 @@ import { StatusBar } from '@/components/AssistantChat/StatusBar'
 import { ComposerButtons } from '@/components/AssistantChat/ComposerButtons'
 import { AttachmentItem } from '@/components/AssistantChat/AttachmentItem'
 import { useTranslation } from '@/lib/use-translation'
-import { getClaudeComposerModelOptions, getNextClaudeComposerModel } from './claudeModelOptions'
+import { getModelOptionsForFlavor, getNextModelForFlavor } from './modelOptions'
 import { getClaudeComposerEffortOptions } from './claudeEffortOptions'
 
 export interface TextInputState {
@@ -266,8 +266,8 @@ export function HappyComposer(props: {
         [agentFlavor]
     )
     const claudeModelOptions = useMemo(
-        () => getClaudeComposerModelOptions(model),
-        [model]
+        () => getModelOptionsForFlavor(agentFlavor, model),
+        [agentFlavor, model]
     )
     const claudeEffortOptions = useMemo(
         () => getClaudeComposerEffortOptions(effort),
@@ -352,9 +352,9 @@ export function HappyComposer(props: {
 
     useEffect(() => {
         const handleGlobalKeyDown = (e: globalThis.KeyboardEvent) => {
-            if (e.key === 'm' && (e.metaKey || e.ctrlKey) && onModelChange && isClaudeFlavor(agentFlavor)) {
+            if (e.key === 'm' && (e.metaKey || e.ctrlKey) && onModelChange && supportsModelChange(agentFlavor)) {
                 e.preventDefault()
-                onModelChange(getNextClaudeComposerModel(model))
+                onModelChange(getNextModelForFlavor(agentFlavor, model))
                 haptic('light')
             }
         }
@@ -439,7 +439,7 @@ export function HappyComposer(props: {
 
     const showCollaborationSettings = Boolean(onCollaborationModeChange && collaborationModeOptions.length > 0)
     const showPermissionSettings = Boolean(onPermissionModeChange && permissionModeOptions.length > 0)
-    const showModelSettings = Boolean(onModelChange && isClaudeFlavor(agentFlavor))
+    const showModelSettings = Boolean(onModelChange && supportsModelChange(agentFlavor))
     const showEffortSettings = Boolean(onEffortChange && isClaudeFlavor(agentFlavor))
     const showSettingsButton = Boolean(showCollaborationSettings || showPermissionSettings || showModelSettings || showEffortSettings)
     const showAbortButton = true

web/src/components/AssistantChat/modelOptions.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it } from 'vitest'
+import { getModelOptionsForFlavor, getNextModelForFlavor } from './modelOptions'
+
+describe('getModelOptionsForFlavor', () => {
+    it('returns Gemini model options for gemini flavor', () => {
+        const options = getModelOptionsForFlavor('gemini')
+        expect(options[0]).toEqual({ value: null, label: 'Default' })
+        expect(options.some((o) => o.value === 'gemini-3-flash-preview')).toBe(true)
+        expect(options.some((o) => o.value === 'gemini-2.5-flash')).toBe(true)
+    })
+
+    it('returns Claude model options for claude flavor', () => {
+        const options = getModelOptionsForFlavor('claude')
+        expect(options[0]).toEqual({ value: null, label: 'Auto' })
+        expect(options.some((o) => o.value === 'sonnet')).toBe(true)
+        expect(options.some((o) => o.value === 'opus')).toBe(true)
+    })
+
+    it('includes custom Gemini model from env/config in options', () => {
+        const options = getModelOptionsForFlavor('gemini', 'gemini-custom-experiment')
+        expect(options.some((o) => o.value === 'gemini-custom-experiment')).toBe(true)
+    })
+
+    it('does not duplicate a preset Gemini model', () => {
+        const options = getModelOptionsForFlavor('gemini', 'gemini-2.5-flash')
+        const flashCount = options.filter((o) => o.value === 'gemini-2.5-flash').length
+        expect(flashCount).toBe(1)
+    })
+})
+
+describe('getNextModelForFlavor', () => {
+    it('cycles Gemini models', () => {
+        const next = getNextModelForFlavor('gemini', null)
+        expect(next).not.toBeNull()
+    })
+
+    it('cycles Claude models', () => {
+        const next = getNextModelForFlavor('claude', null)
+        expect(next).not.toBeNull()
+    })
+})

web/src/components/AssistantChat/modelOptions.ts

@@ -0,0 +1,40 @@
+import { MODEL_OPTIONS } from '@/components/NewSession/types'
+import { getClaudeComposerModelOptions, getNextClaudeComposerModel } from './claudeModelOptions'
+import type { ClaudeComposerModelOption } from './claudeModelOptions'
+
+export type ModelOption = ClaudeComposerModelOption
+
+function getGeminiModelOptions(currentModel?: string | null): ModelOption[] {
+    const options = MODEL_OPTIONS.gemini.map((m) => ({
+        value: m.value === 'auto' ? null : m.value,
+        label: m.label
+    }))
+    const normalized = currentModel?.trim() || null
+    if (normalized && !options.some((o) => o.value === normalized)) {
+        options.splice(1, 0, { value: normalized, label: normalized })
+    }
+    return options
+}
+
+function getNextGeminiModel(currentModel?: string | null): string | null {
+    const options = getGeminiModelOptions(currentModel)
+    const currentIndex = options.findIndex((o) => o.value === (currentModel ?? null))
+    if (currentIndex === -1) {
+        return options[0]?.value ?? null
+    }
+    return options[(currentIndex + 1) % options.length]?.value ?? null
+}
+
+export function getModelOptionsForFlavor(flavor: string | undefined | null, currentModel?: string | null): ModelOption[] {
+    if (flavor === 'gemini') {
+        return getGeminiModelOptions(currentModel)
+    }
+    return getClaudeComposerModelOptions(currentModel)
+}
+
+export function getNextModelForFlavor(flavor: string | undefined | null, currentModel?: string | null): string | null {
+    if (flavor === 'gemini') {
+        return getNextGeminiModel(currentModel)
+    }
+    return getNextClaudeComposerModel(currentModel)
+}

web/src/components/NewSession/types.ts

@@ -1,3 +1,5 @@
+import { GEMINI_MODEL_PRESETS, GEMINI_MODEL_LABELS } from '@hapi/protocol'
+
 export type AgentType = 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode'
 export type SessionType = 'simple' | 'worktree'
 export type CodexReasoningEffort = 'default' | 'low' | 'medium' | 'high' | 'xhigh'
@@ -23,12 +25,8 @@ export const MODEL_OPTIONS: Record<AgentType, { value: string; label: string }[]
     ],
     cursor: [],
     gemini: [
-        { value: 'auto', label: 'Auto' },
-        { value: 'gemini-3.1-pro-preview', label: 'Gemini 3.1 Pro Preview' },
-        { value: 'gemini-3-flash-preview', label: 'Gemini 3 Flash Preview' },
-        { value: 'gemini-2.5-pro', label: 'Gemini 2.5 Pro' },
-        { value: 'gemini-2.5-flash', label: 'Gemini 2.5 Flash' },
-        { value: 'gemini-2.5-flash-lite', label: 'Gemini 2.5 Flash Lite' },
+        { value: 'auto', label: 'Default' },
+        ...GEMINI_MODEL_PRESETS.map(m => ({ value: m, label: GEMINI_MODEL_LABELS[m] })),
     ],
     opencode: [],
 }

web/src/lib/agentFlavorUtils.ts

@@ -13,3 +13,7 @@ export function isCursorFlavor(flavor?: string | null): boolean {
 export function isKnownFlavor(flavor?: string | null): boolean {
     return isClaudeFlavor(flavor) || isCodexFamilyFlavor(flavor) || isCursorFlavor(flavor)
 }
+
+export function supportsModelChange(flavor?: string | null): boolean {
+    return flavor === 'claude' || flavor === 'gemini'
+}