From b2121c963fe65add9514d932b24f7844c82b2d12 Mon Sep 17 00:00:00 2001
From: Dax Raad <d@ironbay.co>
Date: Mon, 2 Feb 2026 00:20:15 -0500
Subject: [PATCH] core: enable plan mode by default

---
 packages/opencode/src/flag/flag.ts      |  1 -
 packages/opencode/src/session/prompt.ts | 28 -------------------------
 packages/opencode/src/tool/registry.ts  |  2 +-
 3 files changed, 1 insertion(+), 30 deletions(-)

diff --git a/packages/opencode/src/flag/flag.ts b/packages/opencode/src/flag/flag.ts
index 64ae801d18..510fdcccfe 100644
--- a/packages/opencode/src/flag/flag.ts
+++ b/packages/opencode/src/flag/flag.ts
@@ -44,7 +44,6 @@ export namespace Flag {
   export const OPENCODE_EXPERIMENTAL_LSP_TY = truthy("OPENCODE_EXPERIMENTAL_LSP_TY")
   export const OPENCODE_EXPERIMENTAL_LSP_TOOL = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_LSP_TOOL")
   export const OPENCODE_DISABLE_FILETIME_CHECK = truthy("OPENCODE_DISABLE_FILETIME_CHECK")
-  export const OPENCODE_EXPERIMENTAL_PLAN_MODE = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_PLAN_MODE")
   export const OPENCODE_EXPERIMENTAL_MARKDOWN = truthy("OPENCODE_EXPERIMENTAL_MARKDOWN")
   export const OPENCODE_MODELS_URL = process.env["OPENCODE_MODELS_URL"]
   export const OPENCODE_MODELS_PATH = process.env["OPENCODE_MODELS_PATH"]
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index 98dce97ba9..d1b527efbb 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -17,7 +17,6 @@ import { ProviderTransform } from "../provider/transform"
 import { SystemPrompt } from "./system"
 import { InstructionPrompt } from "./instruction"
 import { Plugin } from "../plugin"
-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"
@@ -1232,33 +1231,6 @@ export namespace SessionPrompt {
     const userMessage = input.messages.findLast((msg) => msg.info.role === "user")
     if (!userMessage) return input.messages
 
-    // Original logic when experimental plan mode is disabled
-    if (!Flag.OPENCODE_EXPERIMENTAL_PLAN_MODE) {
-      if (input.agent.name === "plan") {
-        userMessage.parts.push({
-          id: Identifier.ascending("part"),
-          messageID: userMessage.info.id,
-          sessionID: userMessage.info.sessionID,
-          type: "text",
-          text: PROMPT_PLAN,
-          synthetic: true,
-        })
-      }
-      const wasPlan = input.messages.some((msg) => msg.info.role === "assistant" && msg.info.agent === "plan")
-      if (wasPlan && input.agent.name === "build") {
-        userMessage.parts.push({
-          id: Identifier.ascending("part"),
-          messageID: userMessage.info.id,
-          sessionID: userMessage.info.sessionID,
-          type: "text",
-          text: BUILD_SWITCH,
-          synthetic: true,
-        })
-      }
-      return input.messages
-    }
-
-    // New plan mode logic when flag is enabled
     const assistantMessage = input.messages.findLast((msg) => msg.info.role === "assistant")
 
     // Switching from plan mode to build mode
diff --git a/packages/opencode/src/tool/registry.ts b/packages/opencode/src/tool/registry.ts
index 7b3a458897..4989e5c2d8 100644
--- a/packages/opencode/src/tool/registry.ts
+++ b/packages/opencode/src/tool/registry.ts
@@ -117,7 +117,7 @@ export namespace ToolRegistry {
       ApplyPatchTool,
       ...(Flag.OPENCODE_EXPERIMENTAL_LSP_TOOL ? [LspTool] : []),
       ...(config.experimental?.batch_tool === true ? [BatchTool] : []),
-      ...(Flag.OPENCODE_EXPERIMENTAL_PLAN_MODE && Flag.OPENCODE_CLIENT === "cli" ? [PlanExitTool, PlanEnterTool] : []),
+      ...(Flag.OPENCODE_CLIENT === "cli" ? [PlanExitTool, PlanEnterTool] : []),
       ...custom,
     ]
   }