AI DevelopmentDecision Matrix10 min readPublished November 8, 2026

Training stage · access rights · product readiness

Base Model or AI Assistant: What Are You Actually Buying?

Distinguish base checkpoints, post-trained models and hosted assistants, then assess the adaptation, licences and operating work behind an AI buying decision.

DA
Digital Applied Team
Senior strategists · Published November 8, 2026
PublishedNovember 8, 2026
UpdatedNovember 10, 2026
Read time10 min

A model release can give you a starting point for training, a system already adapted to follow instructions, or access to a managed product. Those are different purchases, even when all three are described as “AI models.” Before comparing benchmark scores, establish what the supplier provides and what your team must still build.

ERNIE 5.5 Flash Base makes the distinction explicit. Baidu describes the released weights as the checkpoint at the end of pre-training, before mid-training or post-training, intended as a starting point for further adaptation. That can be valuable to a team developing model behaviour. It does not make the checkpoint a finished business assistant. Baidu's release description

For an agency or company buying a practical capability, the decision should connect the required outcome to the remaining work: adaptation, serving, application controls, evaluation and ongoing support. A more flexible starting point can create a larger delivery obligation.

Key takeaways
  1. 01
    Separate the layersTraining stage, access method and product readiness are separate attributes.
  2. 02
    Check the artifactDownloadable weights provide an artifact; they do not establish commercial rights, affordable serving or application quality.
  3. 03
    Own the applicationPost-training can change behaviour without supplying the surrounding product or operating controls.
  4. 04
    Verify portabilityHosted access may support evaluation before weights are downloadable, but portability remains a separate requirement.
  5. 05
    Compare total workCompare the total work needed to deliver an accepted outcome, including maintenance and a credible exit path.

01 — Buying layersSeparate the model, its access route and the product

Start with three independent questions. What behaviour has the model been trained to produce? How can your team access it? What user-facing and operational features come with that access?

A base checkpoint is an artifact from a particular training stage. An instruction-tuned or otherwise post-trained model has undergone additional work to shape behaviour. A hosted API is a way to call a model. An assistant product adds interaction and workflow features around one or more models. These categories can overlap without becoming equivalent.

For example, a provider can host a base checkpoint, or publish the weights of a post-trained model. A polished chat interface may use a hosted model whose weights are unavailable. The presence of a download link therefore answers a different question from whether the model follows your instructions reliably.

Write these attributes separately in a shortlist. Avoid one column called “open” that attempts to cover weight availability, licence permissions, training transparency and deployment control. Each needs its own evidence.

A procurement framework separating training stage, access, product features and operation.
AttributeProcurement questionEvidence to request
Training stageWhat behaviour was deliberately developed?Model card and training description
AccessCan we call, adapt or download this version?Working route and current access terms
Product layerWhat workflow features are included?Demonstration against your requirements
OperationWho keeps it reliable after launch?Named responsibilities and service terms

The table is a buying framework, not a ranking. A suitable hosted assistant can be the right choice for one task while a specialised model-development project needs a checkpoint it can adapt directly.

02 — Starting checkpointUnderstand the work a base checkpoint leaves open

A base model can have substantial language, coding and reasoning capabilities. The question is how those capabilities appear under the intended interaction format and whether they meet the application's behavioural requirements.

Do not assume the checkpoint has been trained for the conversation style, tool protocol, refusal behaviour or output structure your product needs. Some tasks may work with carefully designed prompts; others may require adaptation. Establish that empirically rather than inferring readiness from a model's size.

Baidu's ERNIE release evaluates base checkpoints using a matched evaluation setup and describes further training as an intended use. That comparison is evidence about the released base models under those conditions. It should not be presented as a direct ranking of complete assistant products. ERNIE evaluation setup

For a potential buyer, translate the open work into deliverables. Who will define the target behaviour, prepare examples, run adaptation, evaluate failures and maintain the resulting checkpoint? Which requirements can be met through the application, and which depend on the model changing?

Decision 1
Establish the gap

Our business guide to fine-tuning covers adaptation as a project in its own right. It is useful once a recurring behavioural gap has been demonstrated. Fine-tuning should not become an assumed prerequisite just because a new base checkpoint is available.

Evaluation question
Decision 2
Own the adaptation

A base model is a stronger candidate when the organisation has a specific reason to shape behaviour and the capability to own that work. General interest in controlling AI is not yet a sufficient implementation plan.

Implementation choice

03 — Behavioural changesRecognise what post-training changes—and what it leaves to you

Post-training can shape how a model responds, follows instructions or handles particular kinds of tasks. It does not automatically provide customer accounts, permissions, retrieval, billing, logging or a support process. Those remain product and operating decisions.

Arete-27B provides a compact example. Its model card identifies supervised fine-tuning of Qwen3.8-27B to change selected response tendencies. The intervention concerns model behaviour; it is not a complete application package. The card's details were checked on November 10. Arete model card

For procurement, ask whether the resulting behaviour matches your task. A model adapted for one preference or benchmark may not improve a different workflow. Preserve the distinction between the developer's stated training objective, its reported evaluation and the outcomes your team requires.

Test the surrounding application separately. A model can produce a sensible answer while the product retrieves the wrong document, applies the wrong account permissions or fails to record the result. Conversely, an application with good controls may still need a better model for the task.

Specify acceptance criteria at both levels. Model checks might assess answer correctness, instruction following and suitable uncertainty. Application checks should cover data access, action authorization, failure handling and the user's ability to correct an outcome.

Decision check

This separation makes supplier proposals easier to compare. A vendor offering only adaptation should not be scored as if it includes a managed business assistant. A vendor offering a complete product should explain which parts can be configured and which remain fixed.

04 — Access contractTreat hosted access and portability as separate decisions

A hosted route can let a team evaluate a model without first assembling the infrastructure to operate it. That can shorten the path to learning whether the capability is useful. It does not establish that a later self-hosted deployment will have the same limits, features or economics.

Thinking Machines' November 5 Inkling 2 Small announcement illustrates the distinction. It offered hosted sampling and fine-tuning through Tinker while describing full weights as a planned release after external testing. Hosted use and downloadable deployment were separate states in the announcement. Inkling launch announcement

Avoid treating a planned artifact as an available dependency. If a project requires weights to run in a specified environment, its delivery plan should identify the actual files, applicable terms and supported serving path before relying on them.

For hosted evaluation, record the exact surface being tested. A playground, training service and production inference endpoint can expose different features or limits. The model card's maximum context is not automatically the context available on every service route.

Ask what can be exported: prompts, evaluation cases, application data, trained adapters, complete checkpoints or only outputs. These are different forms of portability. A platform may support export in general while a particular model or account tier does not.

Apply the distinction

A practical buying decision can therefore proceed in stages. Use an eligible hosted route to assess task quality, establish whether adaptation adds value, then compare supported operating options. Keep a mandatory portability requirement visible throughout; do not let a convenient trial silently relax it.

05 — Usage rightsCheck the rights attached to the exact artifact

Weight availability is a technical fact, while permission to use those weights is a contractual question. Record the actual licence for the selected version, including the obligations that follow modification, distribution or commercial use.

ERNIE 5.5 Flash Base uses a custom Model License Agreement v1.0. The text checked on November 10 specifies a territory excluding the European Union, United Kingdom and South Korea, alongside commercial notice, attribution and revenue-related conditions. It should not be described as an Apache 2.0 release. Published ERNIE licence

That is a qualification issue to resolve before procurement, not a footnote to discover after adaptation work begins. A publicly downloadable artifact does not by itself establish permission for a particular operator, region or business model.

Use a brief licence record that identifies the model version, document version, intended use, operating locations and distribution plan. Route unresolved conditions to the person responsible for the organisation's contractual review. Keep the resulting decision with the technical evaluation so a later model swap does not bypass it.

Our open-weight model licence audit provides a structured way to gather those facts. Check hosted terms separately: permission to run a downloaded checkpoint and permission to submit data to a service are different matters.

Next step

Also identify dependencies in a derivative model. The licence displayed on its model card is a useful starting point, but the procurement record should identify the underlying model and any additional materials relevant to the intended use. Do not let an ambiguous “open source” label replace the actual documents.

06 — Total costPrice the remaining work, not just inference

Compare options over the same scope and period. A model API quote may exclude application development; an internal hosting estimate may exclude engineering support; an assistant subscription may include features the team would otherwise build. The figures are not comparable until the included responsibilities are clear.

Separate one-time work from recurring cost. One-time work can include data preparation, evaluation design, integration and adaptation. Recurring work can include inference, reserved capacity, monitoring, updates, review and incident response. Include failed attempts when estimating the cost of an accepted result.

Consider an entirely hypothetical comparison between two routes that meet the same acceptance standard. Route A requires £4,000 of initial work and £1,200 per month thereafter. Route B requires £16,000 initially and £700 per month. These are illustrative inputs, not provider prices or a Digital Applied quotation.

Illustrative costs at a constant monthly rate; not provider prices or a Digital Applied quotation.
PeriodRoute A totalRoute B total
12 months£18,400£24,400
24 months£32,800£32,800
36 months£47,200£41,200

The simple break-even calculation is (£16,000 − £4,000) ÷ (£1,200 − £700) = 24 months. It assumes constant recurring costs, comparable quality and no additional migration or financing costs. If volume, staffing or the model changes, the result changes too.

Our RAG and fine-tuning cost comparison explores a related implementation choice. For procurement, keep the broader question visible: how much work remains before each option delivers the required outcome, and who bears that work?

07 — Delivery ownershipUse a readiness matrix to expose missing ownership

Before selecting a route, map the obligations your team would inherit. A base checkpoint typically leaves more behavioural development to the buyer, while a managed product can cover more of the operating stack. Actual supplier contracts determine the allocation; the following matrix is a set of questions rather than a promise about every offering.

Questions for assigning responsibilities; actual supplier terms determine what is included.
RequirementBase checkpointPost-trained weightsManaged assistant
Desired behaviourEstablish and possibly adaptVerify task fitVerify product fit
ServingArrange a supported runtimeArrange a supported runtimeConfirm service contract
Workflow integrationBuild or procureBuild or procureCheck included connectors
Operating ownershipAssign internally or outsourceAssign internally or outsourceDefine shared responsibilities

For each cell that remains unresolved, name the owner and the evidence needed. “The development team will handle it” is insufficient when the work involves infrastructure, data preparation, evaluation and support with different skills and budgets.

Do not infer deployment requirements from active parameter count alone. Hardware planning also depends on the complete model, weight representation, runtime support, working memory, request length and concurrency. A claim that only some parameters activate per token is not a complete memory or capacity estimate.

Use a representative workload when assessing serving options. Include long requests, concurrent use and required response times, not just one successful prompt. Record whether the configuration is supported and repeatable rather than a demonstration assembled for a single run.

The matrix should make gaps discussable before money is committed. If several critical obligations have no owner, choosing a more complete service may be more valuable than obtaining a model with a marginally better benchmark score.

08 — Procurement trialMake the procurement test small enough to finish

Choose a bounded task with a defined acceptance standard. For example, assess whether the system can produce a source-backed internal answer from approved documents and correctly identify when the evidence is insufficient. Specify the documents, access boundaries and output checks before comparing options.

Evaluate a practical baseline first. That might be an existing hosted assistant or an unchanged post-trained model. The baseline establishes whether the task already works well enough and identifies the specific gaps that justify a more involved route.

Then test the smallest intervention that addresses those gaps. Improving retrieval, the workflow or the instructions may be sufficient. If the evidence points toward adaptation, define what improvement would justify its data and operating costs.

Keep development examples separate from final evaluation cases. Record the exact checkpoint or hosted model, configuration and application version so the result can inform a real purchasing decision. A demonstration with unknown settings is difficult to reproduce and easy to overinterpret.

Finally, test the exit path at a proportionate level. Confirm that the required data and configurations can be recovered, identify what would need rebuilding and record any dependency on an unreleased artifact. Portability becomes useful when it can support an actual move, not merely when a proposal promises flexibility.

Before adoption

The decision document should state the chosen route, why it meets the task, who owns the remaining work and which conditions would trigger reconsideration. That gives the business a durable basis for adoption without pretending today's shortlist is permanent.

Conclusion

Buy the starting point your team can turn into a result

Ask what stage of the solution you are acquiring before asking which model is best. A base checkpoint, post-trained model and managed assistant offer different starting points and obligations. Compare them against one accepted business outcome, with rights, access, adaptation and operating ownership made explicit.

Digital Applied's AI transformation services can help turn a model shortlist into a practical evaluation and procurement decision, including the work required to deliver and maintain the application.

Work with Digital Applied

Choose AI around a defined business outcome

Compare access, rights, adaptation and ongoing ownership against the outcome your application needs.

Model evaluationProcurement scopeOperating ownership
Practical next steps

Choose AI around a defined business outcome

  • →Model evaluation
  • →Procurement scope
  • →Operating ownership
Questions and answers

Frequently asked questions

It is a different starting point. A base checkpoint can be valuable for further training or specialised use, while an assistant-oriented model has undergone additional work intended to shape interactive behaviour; suitability still needs evaluation.

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