1. 修复 src/commands/fork/index.ts — 将空 stub 改为有效的 Command 定义 2. 新增 src/commands/fork/fork.tsx — 完整实现 /fork 命令，复用了 AgentTool 的 fork 子 agent 逻辑 (#221)

* 1. 修复 src/commands/fork/index.ts — 将空 stub 改为有效的 Command 定义
  2. 新增 src/commands/fork/fork.tsx — 完整实现 /fork 命令，复用了 AgentTool 的 fork 子 agent 逻辑

* Update src/commands/fork/fork.tsx

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* fix

---------

Co-authored-by: HitMargin <hitmargin@qq.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/commands/fork/fork.tsx

@@ -0,0 +1,73 @@
+import { feature } from 'bun:bundle'
+import React from 'react'
+import { AgentTool } from '../../tools/AgentTool/AgentTool.js'
+import { isInForkChild } from '../../tools/AgentTool/forkSubagent.js'
+import { logForDebugging } from '../../utils/debug.js'
+import type { LocalJSXCommandOnDone, LocalJSXCommandContext } from '../../types/command.js'
+
+export async function call(
+  onDone: LocalJSXCommandOnDone,
+  context: LocalJSXCommandContext,
+  args: string,
+): Promise<React.ReactNode> {
+  // Check feature flag
+  if (!feature('FORK_SUBAGENT')) {
+    onDone('Fork subagent feature is not enabled. Set FEATURE_FORK_SUBAGENT=1 to enable.', { display: 'system' })
+    return null
+  }
+
+  // Recursive fork guard
+  if (isInForkChild(context.messages)) {
+    onDone('Fork is not available inside a forked worker. Complete your task directly using your tools.', { display: 'system' })
+    return null
+  }
+
+  const directive = args.trim()
+  if (!directive) {
+    onDone('Usage: /fork <directive>\nExample: /fork Fix the null check in validate.ts', { display: 'system' })
+    return null
+  }
+
+  // Find the last assistant message to fork from
+  const lastAssistantMessage = [...context.messages].reverse().find(
+    m => m.type === 'assistant'
+  ) as any // Type assertion to avoid complex type import
+
+  if (!lastAssistantMessage) {
+    onDone('Cannot fork: no assistant response in conversation history.', { display: 'system' })
+    return null
+  }
+
+  try {
+    // Reuse AgentTool logic for fork path.
+    // Omitting subagent_type triggers implicit fork.
+    const input = {
+      prompt: directive,
+      run_in_background: true, // fork always runs async
+      description: `Fork: ${directive.slice(0, 30)}${directive.length > 30 ? '...' : ''}`,
+    }
+
+    // Call AgentTool with proper parameters:
+    // - input: the agent parameters (no subagent_type => fork path)
+    // - toolUseContext: the current context (ToolUseContext)
+    // - canUseTool: permission-check function from context
+    // - assistantMessage: the last assistant message to fork from
+    AgentTool.call(
+      input,
+      context,
+      context.canUseTool,
+      lastAssistantMessage
+    ).catch(error => {
+      logForDebugging(`Fork subagent async error: ${error}`, { level: 'error' })
+    })
+
+    // Notify user that fork has been started
+    onDone(`Forked subagent started with directive: "${directive}"`, { display: 'system' })
+    return null
+  } catch (error) {
+    // Catches synchronous setup errors only
+    logForDebugging(`Fork command setup error: ${error}`, { level: 'error' })
+    onDone(`Fork failed: ${error instanceof Error ? error.message : String(error)}`, { display: 'system' })
+    return null
+  }
+}

src/commands/fork/index.ts

@@ -1,3 +1,11 @@
-// Auto-generated stub — replace with real implementation
-const _default: Record<string, unknown> = {};
-export default _default;
+import type { Command } from '../../commands.js'
+
+const fork = {
+  type: 'local-jsx',
+  name: 'fork',
+  description: 'Fork the current session into a new sub-agent',
+  argumentHint: '<prompt>',
+  load: () => import('./fork.js'),
+} satisfies Command
+
+export default fork