fix: run dangerous path check before auto-allowing rm/rmdir in acceptEdits mode (#246)

In acceptEdits mode, filesystem commands (rm, rmdir, mv, cp, sed, mkdir,
touch) were returned as 'allow' before checkDangerousRemovalPaths ran.
This meant rm -rf ~ and rm -rf / bypassed the dangerous path guard entirely.

Fix:
- Export checkDangerousRemovalPaths from pathValidation.ts
- In modeValidation.ts, call it for rm/rmdir before returning allow
- Safe paths (rm file.txt) continue to auto-allow unchanged
- Dangerous paths (rm -rf ~) now return 'ask' requiring user approval

This is a defense-in-depth guard that matters most for 3P models (local
Ollama, DeepSeek etc.) that lack built-in refusal training and would
blindly execute destructive commands in acceptEdits mode.

Fixes finding 3 from issue #244.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

src/tools/BashTool/modeValidation.ts

@@ -1,8 +1,10 @@
 import type { z } from 'zod/v4'
 import type { ToolPermissionContext } from '../../Tool.js'
 import { splitCommand_DEPRECATED } from '../../utils/bash/commands.js'
+import { getCwd } from '../../utils/cwd.js'
 import type { PermissionResult } from '../../utils/permissions/PermissionResult.js'
 import type { BashTool } from './BashTool.js'
+import { checkDangerousRemovalPaths } from './pathValidation.js'
 
 const ACCEPT_EDITS_ALLOWED_COMMANDS = [
   'mkdir',
@@ -39,6 +41,17 @@ function validateCommandForMode(
     toolPermissionContext.mode === 'acceptEdits' &&
     isFilesystemCommand(baseCmd)
   ) {
+    // Guard: always run dangerous path check for rm/rmdir before auto-allowing.
+    // This prevents rm -rf ~ / rm -rf / from bypassing checkDangerousRemovalPaths
+    // which is otherwise skipped when acceptEdits returns allow early.
+    if (baseCmd === 'rm' || baseCmd === 'rmdir') {
+      const args = trimmedCmd.split(/\s+/).slice(1)
+      const dangerousResult = checkDangerousRemovalPaths(baseCmd, args, getCwd())
+      if (dangerousResult.behavior !== 'passthrough') {
+        return dangerousResult
+      }
+    }
+
     return {
       behavior: 'allow',
       updatedInput: { command: cmd },

src/tools/BashTool/pathValidation.ts

@@ -67,7 +67,7 @@ export type PathCommand =
  * require explicit user approval, even if allowlist rules exist.
  * This prevents catastrophic data loss from commands like `rm -rf /`.
  */
-function checkDangerousRemovalPaths(
+export function checkDangerousRemovalPaths(
   command: 'rm' | 'rmdir',
   args: string[],
   cwd: string,