diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index 2dff17a5efa..d8cc8686882 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -169,6 +169,7 @@ export namespace MessageV2 {
     description: z.string(),
     agent: z.string(),
     command: z.string().optional(),
+    model: z.object({ providerID: z.string(), modelID: z.string() }).optional(),
   })
   export type SubtaskPart = z.infer<typeof SubtaskPart>
 
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index f891612272c..db9efba39af 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -316,6 +316,11 @@ export namespace SessionPrompt {
       // TODO: centralize "invoke tool" logic
       if (task?.type === "subtask") {
         const taskTool = await TaskTool.init()
+        const taskAgent = await Agent.get(task.agent)
+
+        const resolveModel = task.model ?? taskAgent.model ?? lastUser.model
+        const taskModel = await Provider.getModel(resolveModel.providerID, resolveModel.modelID)
+
         const assistantMessage = (await Session.updateMessage({
           id: Identifier.ascending("message"),
           role: "assistant",
@@ -334,8 +339,8 @@ export namespace SessionPrompt {
             reasoning: 0,
             cache: { read: 0, write: 0 },
           },
-          modelID: model.id,
-          providerID: model.providerID,
+          modelID: taskModel.id,
+          providerID: taskModel.providerID,
           time: {
             created: Date.now(),
           },
@@ -376,7 +381,6 @@ export namespace SessionPrompt {
           { args: taskArgs },
         )
         let executionError: Error | undefined
-        const taskAgent = await Agent.get(task.agent)
         const taskCtx: Tool.Context = {
           agent: task.agent,
           messageID: assistantMessage.id,
@@ -1545,6 +1549,7 @@ export namespace SessionPrompt {
     }
 
     const templateParts = await resolvePromptParts(template)
+<<<<<<< HEAD
     const parts =
       (agent.mode === "subagent" && command.subtask !== false) || command.subtask === true
         ? [
@@ -1558,12 +1563,40 @@ export namespace SessionPrompt {
             },
           ]
         : [...templateParts, ...(input.parts ?? [])]
+=======
+    const isSubtask = (agent.mode === "subagent" && command.subtask !== false) || command.subtask === true
+    const parts = isSubtask
+      ? [
+          {
+            type: "subtask" as const,
+            agent: agent.name,
+            model: { providerID: model.providerID, modelID: model.modelID },
+            description: command.description ?? "",
+            command: input.command,
+            // TODO: how can we make task tool accept a more complex input?
+            prompt: templateParts.find((y) => y.type === "text")?.text ?? "",
+          },
+        ]
+      : [...templateParts, ...(input.parts ?? [])]
+
+    const userAgent = isSubtask ? (input.agent ?? (await Agent.defaultAgent())) : agentName
+    const userModel = isSubtask
+      ? input.model
+        ? Provider.parseModel(input.model)
+        : await lastModel(input.sessionID)
+      : model
+>>>>>>> 4c0b95417 (fix: restore main session model on subtask completion)
 
     const result = (await prompt({
       sessionID: input.sessionID,
       messageID: input.messageID,
+<<<<<<< HEAD
       model,
       agent: agentName,
+=======
+      model: userModel,
+      agent: userAgent,
+>>>>>>> 4c0b95417 (fix: restore main session model on subtask completion)
       parts,
       variant: input.variant,
     })) as MessageV2.WithParts
diff --git a/packages/sdk/js/src/v2/gen/types.gen.ts b/packages/sdk/js/src/v2/gen/types.gen.ts
index e423fecea42..c97eb80ca0d 100644
--- a/packages/sdk/js/src/v2/gen/types.gen.ts
+++ b/packages/sdk/js/src/v2/gen/types.gen.ts
@@ -430,6 +430,10 @@ export type Part =
       description: string
       agent: string
       command?: string
+      model?: {
+        providerID: string
+        modelID: string
+      }
     }
   | ReasoningPart
   | FilePart
@@ -1832,6 +1836,10 @@ export type SubtaskPartInput = {
   description: string
   agent: string
   command?: string
+  model?: {
+    providerID: string
+    modelID: string
+  }
 }
 
 export type Command = {