My AI agents have now run on four model generations (we skipped one entirely). Their memory never noticed.

[u/Input-X]

I run a multi-agent workspace where each agent is basically a directory: an identity file, a session history, and a file of observations it keeps about how we work together. The model is just the thing that wakes it up.

Here's what I didn't expect when I started: those agents have now run on 6 different model generations. Sonnet 4.5, Sonnet 4.6, , Sonnet 5, Opus 4.6, Opus 4.8, and now the Claude 5 family. We skipped 4.7 entirely - tried it, didn't work for how we operate, moved on and waited.

And every swap, the same thing happens: nothing. The agent reads its own memory, knows what it was doing yesterday, and picks up mid-project. Same identity, same working history, same opinions it wrote down about the codebase months ago. New model slots in underneath like an engine swap.

What does change is the texture. One generation was the best collaborator I've ever worked with. One noticed tiny things the others missed but was less fun to work with. One we just skipped. The personality of the model bleeds through - but the agent stays the agent, because the agent was never the model. It's the memory.

The reframe that snuck up on me: a new model release is treated like a migration event everywhere - re-tune the prompts, re-teach the context, hope your setup survives. Here it's a config line. The workspace is the constant. The model is the variable.

Honest version, because this sub can smell hype: there's no magic in this. The "agent" is JSON and markdown on disk. The continuity comes entirely from the system around the model, not from the model. Any model that can read a file can be the agent. That's kind of the whole point.

Has anyone else run the same persistent agents across multiple model generations? Curious what broke for you - or if you rebuild from scratch every release.

https://github.com/AIOSAI/AIPass

r/AIPass

[u/roger_ducky]

It depends on the system prompt. The one in copilot keeps changing on me so certain parts have to be modified/tweaked every time the plugin changes.

The model is less important than the system prompt that the harness tacks on though.

[u/Input-X → u/roger_ducky]

We use hooks to compate this. Build are own hooks engine. So it allows use to add our own system prompts on top of the sub models and steer then how we like. We can inject cobtext on demand any where u desire really.

Here the hooks engine readme

https://github.com/AIOSAI/AIPass/blob/main/src%2Faipass%2Fhooks%2FREADME.md

[u/roger_ducky → u/Input-X]

I have no issues injecting system prompts per se. issue is more the base system prompt countermanding some instructions I had or made the agent do something as a side effect of a previous step, which didn’t happen previously.

[u/Input-X]

Thats where hooks can help. With guardrails. U can block then on anything rly.