An enterprise AI stack is easier to understand when its components are separated by responsibility. The model generates or interprets content. Other components establish identity, retrieve information, apply business rules, execute actions, and observe the result. Combining these responsibilities into the word "AI" makes architecture discussions less precise.
A technology stack is the collection of technologies used to build and operate a system. There is no universal AI stack that every organization must purchase. The appropriate design depends on the service, its users, its information, and the consequences of failure. The conceptual architecture here is a starting point for asking those questions.
Begin with the application and its users
The application layer receives a request and presents an outcome. It might be a chat interface, a feature inside an existing business application, or a background process with no conversational interface at all. The interface should make the system's scope understandable.
Identity and authorization establish who is making the request and what that person or service may access. A conversational interface does not justify bypassing existing controls. In an employee-support application, a manager's access to team information should not become every employee's access merely because the information enters a shared search index.
NIST's zero trust architecture guidance rejects implicit trust based solely on network location or ownership. [1] Applied here, the useful principle is to make access decisions explicit at the relevant resources and actions.
Separate the model from the application logic
The model may be accessed through a hosted service or operated within infrastructure the organization manages. That choice changes responsibilities for capacity, upgrades, deployment, and support. It does not remove the need to assess data handling and actual application behavior.
An orchestration layer assembles instructions and context, calls the model or tools, and handles the response. Some applications need only a short sequence of calls. Others need routing, retries, and state management. Add these mechanisms because the workflow requires them, not because a reference architecture includes them.
Conventional code remains a suitable place for explicit rules such as valid account states, transaction limits, or mandatory approvals. The architecture should show which decisions are enforced there and which are proposed by the model.
Add retrieval when the task needs external knowledge
Retrieval-augmented generation, or RAG, supplies relevant external information as context for generating a response. Microsoft's Azure AI Search documentation describes this pattern and its associated retrieval, security, and information-preparation concerns. [2]
Retrieval can use keywords, semantic techniques, vector similarity, or a combination. A vector represents information numerically for comparison. A vector database is one possible component, not a compulsory purchase for every AI application. The search design should follow the content and questions. Our RAG and knowledge systems research explores retrieval further.
For an employee-support service, the important test is whether it finds the applicable policy passage for the authorized user. A larger index or longer context window is not itself evidence of better answers. The application also needs a way to identify the source and avoid treating obsolete material as current.
Keep action tools behind enforceable boundaries
An application may expose APIs that retrieve records, create drafts, or update systems. The model can propose a tool call, but execution should occur through application-controlled interfaces. Those interfaces need validation, authorization, and appropriate limits.
Anthropic's guidance on building effective agents separates two designs: workflows that follow paths written in code, and agents that let the model decide which steps and tools to use. [3] That distinction belongs in an architecture review: a fixed approval sequence has different control requirements from an agent choosing its next action dynamically.
A helpful design question is whether the tool interface is narrower than the underlying system. A task to look up order status usually does not require unrestricted database access. Exposing only the required operation makes the permitted behavior easier to understand and test.
Treat operations as a shared foundation
The diagram places access, policy, testing, logging, and cost controls beside the functional components because they apply to the full path from request to response. Monitoring only the model endpoint leaves the team unable to explain failures caused by retrieval, integration, or application logic.
Record enough information to connect an interaction with its configuration and component outcomes. Track latency and cost at the service level, including repeated calls. A single successful model response can still belong to a failed user transaction if the final write operation did not complete.
Version changes to prompts, model selections, retrieval settings, and tool definitions should be traceable. Anthropic's context-engineering discussion illustrates why the information available during an interaction affects behavior. [4] That makes configuration management relevant to more than application source code.
Buy components against requirements
Before selecting products, draw the simplest version of the proposed service. Label where sensitive information travels, where actions are authorized, and where failures become visible. Then identify capabilities already available in the organization's existing platforms.
A vendor may combine several layers into one offering. That can reduce integration work, but the evaluation should still ask the same questions about permissions, evidence, monitoring, and exit options. Packaging does not eliminate the underlying responsibilities.
The purpose of a stack diagram is to expose those responsibilities. If the team can explain why each component exists, what it depends on, and who operates it, the architecture is useful. If it merely lists fashionable product categories, it has not yet explained how the service will work.
References
- NIST. Zero Trust Architecture, SP 800-207. August 2020.
- Microsoft Learn. Retrieval-Augmented Generation in Azure AI Search. Living documentation.
- Anthropic. Building Effective Agents. December 19, 2024.
- Anthropic. Effective Context Engineering for AI Agents. September 29, 2025.
Sources checked October 2026. CorpExcellence.com articles are best-effort research and analysis, not professional advice.
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