The agent must read a file before editing, and provide the version from the read. Agent ToolsThe agent has filesystem-like tools:Tool Description Read Read file content. Chrome's userScripts API bypasses this, but you must enable the "User scripts" permission in extension settings. Chrome's userScripts API bypasses this, but you must enable the "User scripts" permission in extension settings. CSP Bypass: userScripts API configures a custom world with permissive CSP: script-src 'self' 'unsafe-inline' 'unsafe-eval' .