The long game
Here's a bet we'll make with anyone: whatever model tops the leaderboard the day you read this, it won't be on top in a couple of months. We've watched it happen too many times to think otherwise — Claude Fable 5 was the one to beat, then GPT-5.6 took the crown, and by the time you finish this sentence there's probably a new contender. Model supremacy churns roughly monthly now. That single fact, more than any benchmark, is why we think a model-agnostic harness wins the long game and a single-model tool loses it.
Supremacy is a rental, not a purchase
The frontier labs are locked in an arms race with an absurd cadence. A model launches, tops the boards, gets everyone excited — and six weeks later a competitor leapfrogs it on exactly the workload you care about, or a cheaper lab ships something 95% as good at a tenth of the price. Nobody holds the crown. Our live benchmarks exist partly to document this in real time, and the story they tell is relentless reshuffling.
Now think about what that means for a tool welded to one model. Claude Code runs Claude. Codex CLI runs GPT. When their lab has a great month, you win. When their lab has a rough release — and every lab does — you're stuck riding it out, or you rip out your entire workflow and migrate to whatever's hot, and then migrate again when the crown moves next. You're paying, in switching cost, for a decision the labs make monthly. That is the treadmill, and single-model tools put you on it by design.
Lock-in is a business model, not a feature
Let's be blunt about why so many tools tie you to one lab: it's usually not a technical limitation. It's the business model. Tools that resell inference need you locked to their models, their meter, and their session format, because that's how they make money — on the markup, every token, forever. Model-agnosticism, key portability, and clean exports aren't features they forgot to build. They're features that would break the revenue.
Once you see it, you can't unsee it. When a tool can't run a competing model, ask whether that's because it's hard or because it's unprofitable. Almost always, it's the second. The lock-in is the point. Which means the fix isn't waiting for those tools to add model choice — they won't — it's choosing a tool whose money doesn't depend on you not having it.
What a model-agnostic harness actually buys you
A harness that lets models compete inside it changes the game in three concrete ways.
The leaderboard churn stops touching your workflow. When a new model tops the board, you point a role at it and keep working. No migration, no relearning a tool, no lost sessions. The labs race; you don't. Your workflow becomes a stable thing that outlives any individual model — which is exactly what you want the durable part of your setup to be.
You can pick the right model per task, not per tool. This is the underrated one. Different models are genuinely better at different things — one plans beautifully, another writes tighter code, a third is a ferociously cheap scout. A single-model tool forces one model onto every job. A model-agnostic harness lets you assign the best tool to each role. We go deep on the assignments in the best model for each agent role, but the headline is: matching model to task beats using one great model for everything, every time.
A different lab reviewing catches what the builder misses. When your reviewer is a different model from a different lab than your builder, it doesn't share the builder's blind spots. Same-model self-review approves its own bugs with confidence. Cross-lab review is one of the highest-leverage quality moves available, and it's only possible if your harness can run more than one lab at once.
The comparison, plainly
| When the crown moves | Single-model tool | Model-agnostic harness |
|---|---|---|
| New leader ships | Wait or migrate tools | Point a role at it |
| Your lab has a bad release | Ride it out | Swap to a competitor |
| Cheap model gets good | Can't use it | Route bulk work to it |
| Best-per-task differs | One model, all jobs | Right model per role |
| Reviewing your own builder | Same-lab blind spots | Cross-lab review |
Why this is the long-game bet
Short term, single-model tools can feel simpler — one model, one bill, one thing to learn. And if the model race froze tomorrow and one lab won forever, that simplicity would be the right call. But the race isn't freezing. If anything it's accelerating, with more labs, more releases, and more genuinely-good cheap options every quarter. In that world, optionality compounds. Every month the crown moves, the agnostic setup quietly wins again while the locked-in setup pays another switching cost or eats another suboptimal model.
This is the whole thesis behind why we think most people have AI coding backwards — obsessing over which model when they should be obsessing over the thing wrapped around the models. We argued it at length in why the harness matters, and it's the reason The Vibe Father runs 22 CLIs and 10+ providers side by side instead of betting the whole product on one lab staying ahead. Not because agnosticism is trendy, but because it's the only design that doesn't lose the moment the leaderboard reshuffles — which it will, right on schedule, next month.
Pick the tool that lets the models fight it out inside it. Let the labs run their race. Yours is different, and it's won by the setup that never has to care who's currently winning theirs.