From dae84b50652fc57831c3fee50334b8396b12fa43 Mon Sep 17 00:00:00 2001
From: Ariane Emory <ariane.emory@protonmail.com>
Date: Sat, 31 Jan 2026 00:31:26 -0500
Subject: [PATCH] feat: add experimental.plan_mode config option

Allow enabling experimental plan mode via config file using
experimental.plan_mode property, equivalent to setting
OPENCODE_EXPERIMENTAL_PLAN_MODE environment variable.

The environment variable takes precedence if both are set.
---
 packages/opencode/src/config/config.ts  | 8 ++++++++
 packages/opencode/src/session/prompt.ts | 3 ++-
 packages/opencode/src/tool/registry.ts  | 2 +-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/packages/opencode/src/config/config.ts b/packages/opencode/src/config/config.ts
index 7969e307957..8f3104ee807 100644
--- a/packages/opencode/src/config/config.ts
+++ b/packages/opencode/src/config/config.ts
@@ -1095,6 +1095,7 @@ export namespace Config {
             .positive()
             .optional()
             .describe("Timeout in milliseconds for model context protocol (MCP) requests"),
+          plan_mode: z.boolean().optional().describe("Enable experimental plan mode"),
         })
         .optional(),
     })
@@ -1268,6 +1269,13 @@ export namespace Config {
     return state().then((x) => x.config)
   }
 
+  export async function experimentalPlanMode() {
+    // Environment variable takes precedence
+    if (Flag.OPENCODE_EXPERIMENTAL_PLAN_MODE) return true
+    const config = await get()
+    return config.experimental?.plan_mode === true
+  }
+
   export async function getGlobal() {
     return global()
   }
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index 94eabdef7f4..290de1b481d 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -34,6 +34,7 @@ import { spawn } from "child_process"
 import { Command } from "../command"
 import { $, fileURLToPath } from "bun"
 import { ConfigMarkdown } from "../config/markdown"
+import { Config } from "../config/config"
 import { SessionSummary } from "./summary"
 import { NamedError } from "@opencode-ai/util/error"
 import { fn } from "@/util/fn"
@@ -1202,7 +1203,7 @@ export namespace SessionPrompt {
     if (!userMessage) return input.messages
 
     // Original logic when experimental plan mode is disabled
-    if (!Flag.OPENCODE_EXPERIMENTAL_PLAN_MODE) {
+    if (!(await Config.experimentalPlanMode())) {
       if (input.agent.name === "plan") {
         userMessage.parts.push({
           id: Identifier.ascending("part"),
diff --git a/packages/opencode/src/tool/registry.ts b/packages/opencode/src/tool/registry.ts
index 7b3a4588972..acb2ec02804 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] : []),
+      ...((await Config.experimentalPlanMode()) && Flag.OPENCODE_CLIENT === "cli" ? [PlanExitTool, PlanEnterTool] : []),
       ...custom,
     ]
   }