Product & Engineering

Product & Engineering

Why "Bring Your Own Model" Enterprises Still Need a Context Layer

Why "Bring Your Own Model" Enterprises Still Need a Context Layer

Why "Bring Your Own Model" Enterprises Still Need a Context Layer

Rohan Mahajan

Rohan Mahajan

6 Min

6 Min

Build Connected Systems with Tartan

Automate workflows with integrated data across your customer applications at scale

Enterprises have gotten smart about not marrying a single model provider. 

Procurement teams negotiate multi-model contracts. Engineering teams build routing layers that send different tasks to different providers based on cost and capability. Nobody wants to be locked into one frontier lab’s roadmap when the leaderboard reshuffles every few months. This flexibility is treated as the strategic win, the hedge that protects the enterprise from betting wrong on which model wins.

It is the wrong layer to be optimizing for lock-in risk. Model choice is the part of the stack that is easiest to swap and least likely to be where an enterprise actually gets stuck. The part that quietly determines whether “bring your own model” is a real capability or a slide in a vendor pitch deck is the context and governance layer sitting underneath the model, and almost nobody is asking whether that layer is portable too.

Model flexibility that means nothing

Picture an enterprise that has done the multi-model work properly. They can route a summarization task to one provider, a reasoning-heavy task to another, and swap either one out the moment a better or cheaper option ships. 

On paper, this is exactly the flexibility everyone is telling enterprises to build toward.

Now ask what happens to that flexibility if the connection between those models and the enterprise’s actual data, HRMS records, KYC documents, policy logic, core banking fields, was built specific to one vendor’s tooling, one vendor’s retrieval format, one vendor’s access framework. Swapping the model is trivial. 

Swapping the context layer underneath it is not, because that is where the real integration work lives, the normalization, the entitlement mapping, the governance rules, all of it built once and now load-bearing for however the enterprise reasons over its own data.

This is the lock-in that actually matters, and it is invisible in most vendor evaluations because everyone is comparing models, not the plumbing underneath them. An enterprise can be completely model-agnostic on paper and still be entirely dependent on one vendor’s context architecture in practice, which means the flexibility they paid for in contract terms was never the flexibility that was going to bite them.

Why context gets built vendor-specific by default

This happens for an unglamorous but understandable reason. Every major model provider now offers some version of a retrieval or context layer bundled with their platform, and it is the fastest path to a working prototype. 

Plug the provider’s connector into your systems, use their retrieval format, ship the demo. 

Nobody sets out to build a locked context layer. 

It is simply the path of least resistance when the model provider is also offering to solve the context problem as a convenience feature.

The cost of that convenience shows up later, and it shows up as exactly the kind of dependency multi-model strategies were supposed to prevent. The normalization work, the identity and scope mapping, the governance rules, everything covered in giving AI systems context, gets built once, inside one vendor’s framework, and becomes the thing that is genuinely expensive to redo every time the enterprise wants to route a workload to a different model.

What a model-agnostic context layer actually requires

A context layer that survives model changes has to be architected as independent infrastructure, not a feature of whichever model happens to be in use. That means a few things in practice.

It has to sit above the model layer, not inside it, exposing normalized, governed data through an interface that any model or agent framework can consume, rather than one that only works inside a specific provider’s retrieval pipeline. The normalization work, translating HRMS, ERP, CRM, and core banking schemas into something consistently structured, has to be done once, independent of which model will eventually reason over that data, so it does not need to be rebuilt every time the routing decision changes.

Governance has to live at the same layer. Identity-bound, scoped access, entitlement tied to live HRMS state, audit trails for what was accessed and by what, none of that should be re-implemented per model provider. If governance is bolted onto each model integration separately, an enterprise ends up with as many governance postures as it has model providers, which is not governance at all, it is fragmentation wearing a compliance label.

And it has to be built to accept new model providers as they emerge, without requiring the underlying data relationships to be rebuilt from scratch. The frontier model landscape is going to keep reshuffling for years. A context layer tied to today’s leader is making the same mistake as betting on a single model, just one layer removed from where the risk is visible.

The real long-term infrastructure bet

Frontier model quality is going to keep converging and reshuffling in ways nobody can predict two years out. Betting heavily on any single model’s continued dominance has already proven to be a bad bet more than once. The enterprises that internalized that lesson moved to multi-model strategies specifically to avoid being caught exposed when the ranking changes again.

The same logic applies one layer down, and most enterprises have not applied it yet. A context and governance layer tied to a single vendor’s framework is exactly as risky as a single-model bet, for the same reason: it optimizes for today’s landscape and leaves the enterprise exposed the moment that landscape shifts, except the exposure here is harder to see because it hides inside integration work that looks finished rather than inside a model leaderboard everyone is already watching.

The actual long-term infrastructure bet is not which model wins. It is whether the enterprise’s data, structured, normalized, and governed, is portable across whichever model or combination of models ends up being the right one for a given task, this year and in whatever configuration exists three years from now. That portability does not happen by default. 

It has to be built as its own layer, deliberately kept independent of any single model provider’s tooling, or the multi-model strategy an enterprise thinks it has is really just a multi-model strategy for the parts that were always easy to swap.

The question worth asking

Most enterprises can already answer which models they are using and how they are routing between them. Far fewer can answer whether the context feeding those models would survive a change in that routing untouched. 

webThat second question is the one that actually determines whether an enterprise’s AI strategy is durable, or whether it just looks flexible on the surface while quietly depending on one vendor’s plumbing to keep working at all.

One platform. Across workflows.

One platform. Across workflows.

Tartan helps teams integrate, enrich, and validate critical customer data across workflows, not as a one-off step but as an infrastructure layer.

Tartan helps teams integrate, enrich, and validate critical customer data across workflows, not as a one-off step but as an infrastructure layer.

Tartan helps teams integrate, enrich, and validate critical customer data across workflows, not as a one-off step but as an infrastructure layer.