remove unnecessary deep clones from session loop and LLM stream (#14354)

2 files changed, 4 insertions, 11 deletions

diff --git a/packages/opencode/src/session/llm.ts b/packages/opencode/src/session/llm.ts
index fa8803912..4e42fb0d2 100644
--- a/packages/opencode/src/session/llm.ts
+++ b/packages/opencode/src/session/llm.ts
@@ -11,7 +11,7 @@ import {
   tool,
   jsonSchema,
 } from "ai"
-import { clone, mergeDeep, pipe } from "remeda"
+import { mergeDeep, pipe } from "remeda"
 import { ProviderTransform } from "@/provider/transform"
 import { Config } from "@/config/config"
 import { Instance } from "@/project/instance"
@@ -80,15 +80,11 @@ export namespace LLM {
     )
 
     const header = system[0]
-    const original = clone(system)
     await Plugin.trigger(
       "experimental.chat.system.transform",
       { sessionID: input.sessionID, model: input.model },
       { system },
     )
-    if (system.length === 0) {
-      system.push(...original)
-    }
     // rejoin to maintain 2-part structure for caching if header unchanged
     if (system.length > 2 && system[0] === header) {
       const rest = system.slice(1)
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index 6ca93979e..f9229de88 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -22,7 +22,6 @@ import PROMPT_PLAN from "../session/prompt/plan.txt"
 import BUILD_SWITCH from "../session/prompt/build-switch.txt"
 import MAX_STEPS from "../session/prompt/max-steps.txt"
 import { defer } from "../util/defer"
-import { clone } from "remeda"
 import { ToolRegistry } from "../tool/registry"
 import { MCP } from "../mcp"
 import { LSP } from "../lsp"
@@ -627,11 +626,9 @@ export namespace SessionPrompt {
         })
       }
 
-      const sessionMessages = clone(msgs)
-
       // Ephemerally wrap queued user messages with a reminder to stay on track
       if (step > 1 && lastFinished) {
-        for (const msg of sessionMessages) {
+        for (const msg of msgs) {
           if (msg.info.role !== "user" || msg.info.id <= lastFinished.id) continue
           for (const part of msg.parts) {
             if (part.type !== "text" || part.ignored || part.synthetic) continue
@@ -648,7 +645,7 @@ export namespace SessionPrompt {
         }
       }
 
-      await Plugin.trigger("experimental.chat.messages.transform", {}, { messages: sessionMessages })
+      await Plugin.trigger("experimental.chat.messages.transform", {}, { messages: msgs })
 
       // Build system prompt, adding structured output instruction if needed
       const system = [...(await SystemPrompt.environment(model)), ...(await InstructionPrompt.system())]
@@ -664,7 +661,7 @@ export namespace SessionPrompt {
         sessionID,
         system,
         messages: [
-          ...MessageV2.toModelMessages(sessionMessages, model),
+          ...MessageV2.toModelMessages(msgs, model),
           ...(isLastStep
             ? [
                 {