Windsurf's Cascade agent is being retired this week, with Cognition's Devin Local set to take its place, following last year's ownership shakeup that saw Cognition acquire the Windsurf product and brand. Most of the discussion I've seen focuses on capability differences between the two agents. There's a narrower, more practical question worth asking any time this kind of transition happens.
The question that actually matters for existing apps
If you built something using the outgoing agent, does the replacement agent understand the patterns and decisions the old one already made in your codebase, including the security-relevant ones, or does it start reasoning about your app fresh, with its own defaults, that may not match what's already there? A new agent stepping into an established codebase can behave differently around exactly the kind of decision, an access rule, an authentication check, a permission structure, that's easy to overlook if it isn't flagged directly during the transition.
Why this is worth checking rather than assuming
Two different agents, even from related companies, can have genuinely different defaults and tendencies baked into how they write code. That's not a criticism of either one, it's simply true of any two systems built by different teams with different priorities. An app that was fine under one agent's patterns isn't automatically fine the moment a different agent starts touching the same code, especially around anything an agent might quietly refactor without being asked to.
What to actually do if you're going through this transition
- Before letting a new agent make significant changes to an existing app, re-run your own basic checks afterward, not just before, the same ownership and access-control tests worth running after any major change.
- Pay particular attention to anything the new agent touches that relates to authentication, permissions, or data access, even if you didn't explicitly ask it to change that part.
- Don't assume continuity between agents just because one is replacing the other under the same company. Different systems can make different assumptions.
The broader pattern
Agent transitions like this one are going to keep happening as this space consolidates and evolves, and each one is worth treating as a legitimate trigger for a fresh check, the same way shipping a major new feature would be. The tool changed under your app. That's reason enough to look again, regardless of how much you trust either agent individually.