The decision path
Work through these in order — most real systems land on the first "yes" they hit, not the most sophisticated option available:
- Is the answer a precise, structured record — an order status, a row count, an exact figure? → Tool/API integration or Text-to-SQL.
- Does the answer depend more on relationships between entities than on text similarity — org hierarchies, compliance lineage, dependency chains? → Knowledge Graph, usually combined with retrieval.
- Does completing the task require multiple steps, tool calls, or a decision about what to do next based on an intermediate result? → Agentic architecture — bounded and governed, not open-ended.
- Does the underlying knowledge change frequently, and does the answer need to reflect that? → RAG.
- Is the actual need a change in the model's behavior, tone, or output format, applied consistently? → Fine-tuning.
- None of the above cleanly fits alone? → Hybrid — which is where most production enterprise systems actually end up.
Comparison
| Approach | Best when | Weakness | Avoid when |
|---|---|---|---|
| RAG | Knowledge changes frequently; answers must be grounded and current | Retrieval quality bottlenecks everything; weak on precise structured lookups | The need is an exact record, not synthesized knowledge |
| Fine-tuning | Behavior, tone, or output format must change consistently | Expensive to keep current; doesn't solve "must reflect this week's data" | The underlying knowledge changes often |
| Tool / API integration | A real-time action or a deterministic system lookup is needed | Requires a safe, well-scoped tool or API to already exist | The need is synthesizing unstructured knowledge across documents |
| Text-to-SQL | Structured data questions against a known, stable schema | Brittle against ambiguous language and schema drift; needs strong guardrails | Row/column authorization isn't solved first, or the schema is unstable |
| Knowledge Graph | Relationships between entities matter more than raw content | Significant upfront modeling effort | Content is loosely structured with no stable entity model |
| Agentic | Multi-step tasks needing orchestration and in-flight decisions | Highest complexity, cost, and governance burden of any option here | A fixed workflow would solve the same problem — the most over-selected option relative to actual need |
| Hybrid | Real enterprise systems, almost always | More moving parts to design, evaluate, and observe | Used as an excuse to avoid making any actual architecture decision |
Reference Architecture — most production systems combine approaches rather than picking one purely.
AQEVON's point of view
"Agentic" is not automatically the sophisticated choice — a large share of agent projects are workflows wearing an agent costume, taking on autonomy risk and cost for no functional benefit. The right architecture question is never "which is more advanced," it's "which one matches how this specific answer actually needs to be produced."