feat: add variant support for subagents (#7138) [alt of #7140]

.opencode/agent/duplicate-pr.md

@@ -3,6 +3,7 @@ mode: primary
 hidden: true
 model: opencode/claude-haiku-4-5
 color: "#E67E22"
+variant: "high"
 tools:
   "*": false
   "github-pr-search": true

.opencode/agent/triage.md

@@ -3,6 +3,7 @@ mode: primary
 hidden: true
 model: opencode/claude-haiku-4-5
 color: "#44BA81"
+variant: "high"
 tools:
   "*": false
   "github-triage": true

packages/app/src/components/prompt-input.tsx

@@ -1051,7 +1051,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
       providerID: currentModel.provider.id,
     }
     const agent = currentAgent.name
-    const variant = local.model.variant.current()
+    const variant = local.model.variant.effective()
 
     const clearInput = () => {
       prompt.reset()
@@ -1539,9 +1539,11 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
               <Match when={store.mode === "normal"}>
                 <TooltipKeybind placement="top" title="Cycle agent" keybind={command.keybind("agent.cycle")}>
                   <Select
-                    options={local.agent.list().map((agent) => agent.name)}
-                    current={local.agent.current()?.name ?? ""}
-                    onSelect={local.agent.set}
+                    options={local.agent.list()}
+                    value={(a) => a.name}
+                    label={(a) => (a.variant ? `${a.name} (${a.variant})` : a.name)}
+                    current={local.agent.current()}
+                    onSelect={(a) => a && local.agent.set(a.name)}
                     class="capitalize"
                     variant="ghost"
                   />
@@ -1577,7 +1579,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
                       class="text-text-base _hidden group-hover/prompt-input:inline-block"
                       onClick={() => local.model.variant.cycle()}
                     >
-                      <span class="capitalize text-12-regular">{local.model.variant.current() ?? "Default"}</span>
+                      <span class="capitalize text-12-regular">{local.model.variant.effective() ?? "Default"}</span>
                     </Button>
                   </TooltipKeybind>
                 </Show>

packages/app/src/context/local.tsx

@@ -294,6 +294,9 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
             const key = `${m.provider.id}/${m.id}`
             return store.variant?.[key]
           },
+          effective() {
+            return this.current() ?? agent.current()?.variant
+          },
           list() {
             const m = current()
             if (!m) return []
@@ -313,12 +316,12 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
           cycle() {
             const variants = this.list()
             if (variants.length === 0) return
-            const currentVariant = this.current()
-            if (!currentVariant) {
+            const effective = this.effective()
+            if (!effective) {
               this.set(variants[0])
               return
             }
-            const index = variants.indexOf(currentVariant)
+            const index = variants.indexOf(effective)
             if (index === -1 || index === variants.length - 1) {
               this.set(undefined)
               return

packages/opencode/src/agent/agent.ts

@@ -33,6 +33,7 @@ export namespace Agent {
         })
         .optional(),
       prompt: z.string().optional(),
+      variant: z.string().optional(),
       options: z.record(z.string(), z.any()),
       steps: z.number().int().positive().optional(),
     })
@@ -197,6 +198,7 @@ export namespace Agent {
           native: false,
         }
       if (value.model) item.model = Provider.parseModel(value.model)
+      if (value.variant) item.variant = value.variant
       item.prompt = value.prompt ?? item.prompt
       item.description = value.description ?? item.description
       item.temperature = value.temperature ?? item.temperature

packages/opencode/src/cli/cmd/tui/component/dialog-agent.tsx

@@ -9,10 +9,12 @@ export function DialogAgent() {
 
   const options = createMemo(() =>
     local.agent.list().map((item) => {
+      const desc = item.native ? "native" : item.description
+      const variant = item.variant ? ` (${item.variant})` : ""
       return {
         value: item.name,
         title: item.name,
-        description: item.native ? "native" : item.description,
+        description: desc ? desc + variant : variant.trim(),
       }
     }),
   )

packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx

@@ -697,8 +697,8 @@ export function Prompt(props: PromptProps) {
   const showVariant = createMemo(() => {
     const variants = local.model.variant.list()
     if (variants.length === 0) return false
-    const current = local.model.variant.current()
-    return !!current
+    const effective = local.model.variant.effective()
+    return !!effective
   })
 
   const spinnerDef = createMemo(() => {
@@ -944,7 +944,7 @@ export function Prompt(props: PromptProps) {
                   <Show when={showVariant()}>
                     <text fg={theme.textMuted}>·</text>
                     <text>
-                      <span style={{ fg: theme.warning, bold: true }}>{local.model.variant.current()}</span>
+                      <span style={{ fg: theme.warning, bold: true }}>{local.model.variant.effective()}</span>
                     </text>
                   </Show>
                 </box>

packages/opencode/src/cli/cmd/tui/context/local.tsx

@@ -314,6 +314,9 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
             const key = `${m.providerID}/${m.modelID}`
             return modelStore.variant[key]
           },
+          effective() {
+            return this.current() ?? agent.current().variant
+          },
           list() {
             const m = currentModel()
             if (!m) return []
@@ -332,12 +335,12 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
           cycle() {
             const variants = this.list()
             if (variants.length === 0) return
-            const current = this.current()
-            if (!current) {
+            const effective = this.effective()
+            if (!effective) {
               this.set(variants[0])
               return
             }
-            const index = variants.indexOf(current)
+            const index = variants.indexOf(effective)
             if (index === -1 || index === variants.length - 1) {
               this.set(undefined)
               return

packages/opencode/src/config/config.ts

@@ -532,6 +532,7 @@ export namespace Config {
   export const Agent = z
     .object({
       model: z.string().optional(),
+      variant: z.string().optional().describe("Default variant to use for this agent"),
       temperature: z.number().optional(),
       top_p: z.number().optional(),
       prompt: z.string().optional(),
@@ -563,6 +564,7 @@ export namespace Config {
       const knownKeys = new Set([
         "name",
         "model",
+        "variant",
         "prompt",
         "description",
         "temperature",

packages/opencode/src/session/llm.ts

@@ -88,8 +88,8 @@ export namespace LLM {
     const auth = await Auth.get(input.model.providerID)
     const isCodex = provider.id === "openai" && auth?.type === "oauth"
 
-    const variant =
-      !input.small && input.model.variants && input.user.variant ? input.model.variants[input.user.variant] : {}
+    const selectedVariant = input.user.variant ?? input.agent.variant
+    const variant = !input.small && input.model.variants && selectedVariant ? input.model.variants[selectedVariant] : {}
     const base = input.small
       ? ProviderTransform.smallOptions(input.model)
       : ProviderTransform.options(input.model, input.sessionID, provider.options)

packages/opencode/src/session/prompt.ts

@@ -814,7 +814,7 @@ export namespace SessionPrompt {
       agent: agent.name,
       model: input.model ?? agent.model ?? (await lastModel(input.sessionID)),
       system: input.system,
-      variant: input.variant,
+      variant: input.variant ?? agent.variant,
     }
 
     const parts = await Promise.all(

packages/opencode/src/tool/task.ts

@@ -143,6 +143,11 @@ export const TaskTool = Tool.define("task", async (ctx) => {
           providerID: model.providerID,
         },
         agent: agent.name,
+        // Use subagent's configured variant (respects explicit per-agent config).
+        // Parent's --variant override does NOT cascade to subagents intentionally:
+        // if user configured oracle with variant: "high", that intent should be honored
+        // even when parent session uses --variant low.
+        variant: agent.variant,
         tools: {
           todowrite: false,
           todoread: false,

packages/sdk/js/src/v2/gen/types.gen.ts

@@ -1315,6 +1315,10 @@ export type PermissionConfig =
 
 export type AgentConfig = {
   model?: string
+  /**
+   * Default variant to use for this agent
+   */
+  variant?: string
   temperature?: number
   top_p?: number
   prompt?: string
@@ -2001,6 +2005,7 @@ export type Agent = {
     providerID: string
   }
   prompt?: string
+  variant?: string
   options: {
     [key: string]: unknown
   }

packages/sdk/openapi.json

@@ -8654,6 +8654,10 @@
           "model": {
             "type": "string"
           },
+          "variant": {
+            "description": "Default variant to use for this agent",
+            "type": "string"
+          },
           "temperature": {
             "type": "number"
           },
@@ -10291,6 +10295,9 @@
           "prompt": {
             "type": "string"
           },
+          "variant": {
+            "type": "string"
+          },
           "options": {
             "type": "object",
             "propertyNames": {