Perplexity's Agent Skills Need an Undo Path Before They Need More Skills

Perplexity added "Skills" to its Agent API, letting developers compose built-in and custom skills for more complex agent outputs. More skills mean more actions, and more actions mean more ways to produce an irreversible change. Before you add a fifth skill to your agent, make sure the first four have an undo path. The undo problem An agent skill that writes, sends, publishes, or deploys is an irreversible action if there is no rollback. The more skills an agent has, the more irreversible actions it can take in a single session. A chain of skills (research → draft → format → publish) can complete before a human notices the first step was wrong. The undo contract Every agent skill should declare: { "skill_name" : "publish_to_blog" , "action_type" : "write" , "reversible" : true , "undo_method" : "set_published_false" , "undo_timeout_seconds" : 3600 , "undo_side_effects" : [ "SEO index will retain the URL for up to 24h" ] } If reversible is false , the skill should require explicit human approval before execution. A skill registry with undo support # skill_registry.py """ Registers agent skills with undo metadata. Blocks irreversible skills from running without explicit approval. """ from dataclasses import dataclass from typing import Optional , Callable import json @dataclass class Skill : name : str action_type : str # "read", "write", "send", "deploy" reversible : bool undo_fn : Optional [ Callable ] = None undo_timeout_seconds : int = 3600 side_effects : str = "" requires_approval : bool = False class SkillRegistry : def __init__ ( self ): self . skills = {} self . execution_log = [] def register ( self , skill : Skill ): # Irreversible write/send/deploy skills require approval if not skill . reversible and skill . action_type in ( " write " , " send " , " deploy " ): skill . requires_approval = True self . skills [ skill . name ] = skill def execute ( self , skill_name : str , inputs : dict , approved : bool = False ): skill = self . skills . get ( skill_name ) i