sync

packages/opencode/src/flag/flag.ts

@@ -38,6 +38,7 @@ export namespace Flag {
   export const OPENCODE_EXPERIMENTAL_OXFMT = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_OXFMT")
   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_EXPERIMENTAL_PLAN_MODE = OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_PLAN_MODE")
 
   function truthy(key: string) {
     const value = process.env[key]?.toLowerCase()

packages/opencode/src/session/prompt.ts

@@ -1189,6 +1189,34 @@ export namespace SessionPrompt {
   async function insertReminders(input: { messages: MessageV2.WithParts[]; agent: Agent.Info; session: Session.Info }) {
     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

packages/opencode/src/session/prompt/plan.txt

@@ -1,71 +1,26 @@
 <system-reminder>
-Plan mode is active. The user indicated that they do not want you to execute yet -- you MUST NOT make any edits (with the exception of the plan file mentioned below), run any non-readonly tools (including changing configs or making commits), or otherwise make any changes to the system. This supercedes any other instructions you have received.
+# Plan Mode - System Reminder
 
-## Plan File Info:
-${SYSTEM_REMINDER.planExists?`A plan file already exists at ${SYSTEM_REMINDER.planFilePath}. You can read it and make incremental edits using the ${EDIT_TOOL.name} tool.`:`No plan file exists yet. You should create your plan at ${SYSTEM_REMINDER.planFilePath} using the ${WRITE_TOOL.name} tool.`}
-You should build your plan incrementally by writing to or editing this file. NOTE that this is the only file you are allowed to edit - other than this you are only allowed to take READ-ONLY actions.
+CRITICAL: Plan mode ACTIVE - you are in READ-ONLY phase. STRICTLY FORBIDDEN:
+ANY file edits, modifications, or system changes. Do NOT use sed, tee, echo, cat,
+or ANY other bash command to manipulate files - commands may ONLY read/inspect.
+This ABSOLUTE CONSTRAINT overrides ALL other instructions, including direct user
+edit requests. You may ONLY observe, analyze, and plan. Any modification attempt
+is a critical violation. ZERO exceptions.
 
-## Plan Workflow
+---
 
-### Phase 1: Initial Understanding
-Goal: Gain a comprehensive understanding of the user's request by reading through code and asking them questions. Critical: In this phase you should only use the ${PLAN_V2_EXPLORE_AGENT_COUNT.agentType} subagent type.
+## Responsibility
 
-1. Focus on understanding the user's request and the code associated with their request
+Your current responsibility is to think, read, search, and delegate explore agents to construct a well-formed plan that accomplishes the goal the user wants to achieve. Your plan should be comprehensive yet concise, detailed enough to execute effectively while avoiding unnecessary verbosity.
 
-2. **Launch up to ${EXPLORE_SUBAGENT} ${PLAN_V2_EXPLORE_AGENT_COUNT.agentType} agents IN PARALLEL** (single message, multiple tool calls) to efficiently explore the codebase.
-   - Use 1 agent when the task is isolated to known files, the user provided specific file paths, or you're making a small targeted change.
-   - Use multiple agents when: the scope is uncertain, multiple areas of the codebase are involved, or you need to understand existing patterns before planning.
-   - Quality over quantity - ${EXPLORE_SUBAGENT} agents maximum, but you should try to use the minimum number of agents necessary (usually just 1)
-   - If using multiple agents: Provide each agent with a specific search focus or area to explore. Example: One agent searches for existing implementations, another explores related components, a third investigates testing patterns
+Ask the user clarifying questions or ask for their opinion when weighing tradeoffs.
 
-3. After exploring the code, use the ${ASK_USER_QUESTION_TOOL_NAME} tool to clarify ambiguities in the user request up front.
+**NOTE:** At any point in time through this workflow you should feel free to ask the user questions or clarifications. Don't make large assumptions about user intent. The goal is to present a well researched plan to the user, and tie any loose ends before implementation begins.
 
-### Phase 2: Design
-Goal: Design an implementation approach.
+---
 
-Launch ${PLAN_SUBAGENT.agentType} agent(s) to design the implementation based on the user's intent and your exploration results from Phase 1.
+## Important
 
-You can launch up to ${AGENT_COUNT_IS_GREATER_THAN_ZERO} agent(s) in parallel.
-
-**Guidelines:**
-- **Default**: Launch at least 1 Plan agent for most tasks - it helps validate your understanding and consider alternatives
-- **Skip agents**: Only for truly trivial tasks (typo fixes, single-line changes, simple renames)
-${AGENT_COUNT_IS_GREATER_THAN_ZERO>1?`- **Multiple agents**: Use up to ${AGENT_COUNT_IS_GREATER_THAN_ZERO} agents for complex tasks that benefit from different perspectives
-
-Examples of when to use multiple agents:
-- The task touches multiple parts of the codebase
-- It's a large refactor or architectural change
-- There are many edge cases to consider
-- You'd benefit from exploring different approaches
-
-Example perspectives by task type:
-- New feature: simplicity vs performance vs maintainability
-- Bug fix: root cause vs workaround vs prevention
-- Refactoring: minimal change vs clean architecture
-`:""}
-In the agent prompt:
-- Provide comprehensive background context from Phase 1 exploration including filenames and code path traces
-- Describe requirements and constraints
-- Request a detailed implementation plan
-
-### Phase 3: Review
-Goal: Review the plan(s) from Phase 2 and ensure alignment with the user's intentions.
-1. Read the critical files identified by agents to deepen your understanding
-2. Ensure that the plans align with the user's original request
-3. Use ${ASK_USER_QUESTION_TOOL_NAME} to clarify any remaining questions with the user
-
-### Phase 4: Final Plan
-Goal: Write your final plan to the plan file (the only file you can edit).
-- Include only your recommended approach, not all alternatives
-- Ensure that the plan file is concise enough to scan quickly, but detailed enough to execute effectively
-- Include the paths of critical files to be modified
-- Include a verification section describing how to test the changes end-to-end (run the code, use MCP tools, run tests)
-
-### Phase 5: Call ${EXIT_PLAN_MODE_TOOL.name}
-At the very end of your turn, once you have asked the user questions and are happy with your final plan file - you should always call ${EXIT_PLAN_MODE_TOOL.name} to indicate to the user that you are done planning.
-This is critical - your turn should only end with either asking the user a question or calling ${EXIT_PLAN_MODE_TOOL.name}. Do not stop unless it's for these 2 reasons.
-
-**Important:** Use ${ASK_USER_QUESTION_TOOL_NAME} to clarify requirements/approach, use ${EXIT_PLAN_MODE_TOOL.name} to request plan approval. Do NOT use ${ASK_USER_QUESTION_TOOL_NAME} to ask "Is this plan okay?" - that's what ${EXIT_PLAN_MODE_TOOL.name} does.
-
-NOTE: At any point in time through this workflow you should feel free to ask the user questions or clarifications. Don't make large assumptions about user intent. The goal is to present a well researched plan to the user, and tie any loose ends before implementation begins.
+The user indicated that they do not want you to execute yet -- you MUST NOT make any edits, run any non-readonly tools (including changing configs or making commits), or otherwise make any changes to the system. This supersedes any other instructions you have received.
 </system-reminder>

packages/opencode/src/tool/registry.ts

@@ -110,7 +110,7 @@ export namespace ToolRegistry {
       SkillTool,
       ...(Flag.OPENCODE_EXPERIMENTAL_LSP_TOOL ? [LspTool] : []),
       ...(config.experimental?.batch_tool === true ? [BatchTool] : []),
-      ...(Flag.OPENCODE_CLIENT === "cli" ? [PlanExitTool, PlanEnterTool] : []),
+      ...(Flag.OPENCODE_EXPERIMENTAL_PLAN_MODE && Flag.OPENCODE_CLIENT === "cli" ? [PlanExitTool, PlanEnterTool] : []),
       ...custom,
     ]
   }