diff --git a/src/config/globalConfig.ts b/src/config/globalConfig.ts
index 4e4f5ca..141f5d6 100644
--- a/src/config/globalConfig.ts
+++ b/src/config/globalConfig.ts
@@ -35,6 +35,7 @@ export function loadGlobalConfig(): GlobalConfig {
       enabled: parsed.debug.enabled,
       logFile: parsed.debug.log_file,
     } : undefined,
+    worktreeDir: parsed.worktree_dir,
   };
 }
 
@@ -57,6 +58,9 @@ export function saveGlobalConfig(config: GlobalConfig): void {
       log_file: config.debug.logFile,
     };
   }
+  if (config.worktreeDir) {
+    raw.worktree_dir = config.worktreeDir;
+  }
   writeFileSync(configPath, stringifyYaml(raw), 'utf-8');
 }
 
diff --git a/src/models/schemas.ts b/src/models/schemas.ts
index 0f3ae37..8cb0db0 100644
--- a/src/models/schemas.ts
+++ b/src/models/schemas.ts
@@ -127,6 +127,8 @@ export const GlobalConfigSchema = z.object({
   provider: z.enum(['claude', 'codex', 'mock']).optional().default('claude'),
   model: z.string().optional(),
   debug: DebugConfigSchema.optional(),
+  /** Directory for worktrees. If empty, uses ../{tree-name} relative to project */
+  worktree_dir: z.string().optional(),
 });
 
 /** Project config schema */
diff --git a/src/models/types.ts b/src/models/types.ts
index ec22dda..39cf422 100644
--- a/src/models/types.ts
+++ b/src/models/types.ts
@@ -160,6 +160,8 @@ export interface GlobalConfig {
   provider?: 'claude' | 'codex' | 'mock';
   model?: string;
   debug?: DebugConfig;
+  /** Directory for worktrees. If empty, uses ../{tree-name} relative to project */
+  worktreeDir?: string;
 }
 
 /** Project-level configuration */
diff --git a/src/task/worktree.ts b/src/task/worktree.ts
index 4caedbc..d460a2e 100644
--- a/src/task/worktree.ts
+++ b/src/task/worktree.ts
@@ -9,7 +9,7 @@ import * as path from 'node:path';
 import { execFileSync } from 'node:child_process';
 import { createLogger } from '../utils/debug.js';
 import { slugify } from '../utils/slug.js';
-import { isPathSafe } from '../config/paths.js';
+import { loadGlobalConfig } from '../config/globalConfig.js';
 
 const log = createLogger('worktree');
 
@@ -37,29 +37,45 @@ function generateTimestamp(): string {
 }
 
 /**
- * Resolve the worktree path based on options.
- * Validates that custom paths stay within the project directory.
+ * Resolve the worktree path based on options and global config.
  *
- * @throws Error if a custom path escapes projectDir (path traversal)
+ * Priority:
+ * 1. Custom path in options.worktree (string)
+ * 2. worktree_dir from config.yaml (if set)
+ * 3. Default: ../{tree-name} (outside project to avoid Claude Code project detection issues)
  */
 function resolveWorktreePath(projectDir: string, options: WorktreeOptions): string {
+  const timestamp = generateTimestamp();
+  const slug = slugify(options.taskSlug);
+  const dirName = slug ? `${timestamp}-${slug}` : timestamp;
+
+  // Custom path specified in task options
   if (typeof options.worktree === 'string') {
     const resolved = path.isAbsolute(options.worktree)
       ? options.worktree
       : path.resolve(projectDir, options.worktree);
-
-    if (!isPathSafe(projectDir, resolved)) {
-      throw new Error(`Worktree path escapes project directory: ${options.worktree}`);
-    }
-
     return resolved;
   }
 
-  // worktree: true → .takt/worktrees/{timestamp}-{task-slug}/
-  const timestamp = generateTimestamp();
-  const slug = slugify(options.taskSlug);
-  const dirName = slug ? `${timestamp}-${slug}` : timestamp;
-  return path.join(projectDir, '.takt', 'worktrees', dirName);
+  // Load config to check for worktree_dir setting
+  let worktreeBaseDir: string | undefined;
+  try {
+    const globalConfig = loadGlobalConfig();
+    worktreeBaseDir = globalConfig.worktreeDir;
+  } catch {
+    // Config not found, use default
+  }
+
+  if (worktreeBaseDir) {
+    // Use configured worktree directory
+    const resolved = path.isAbsolute(worktreeBaseDir)
+      ? worktreeBaseDir
+      : path.resolve(projectDir, worktreeBaseDir);
+    return path.join(resolved, dirName);
+  }
+
+  // Default: ../{tree-name} (sibling to project directory)
+  return path.join(projectDir, '..', dirName);
 }
 
 /**