Agents don't run on chatbot leaderboards. The model that wins your tool loop is decided by function-calling reliability, agentic benchmarks, and an "agent tax" the headline price hides.
Both bolt a quality check onto RAG, but they fix different failures at different points — and the choice comes down to one question: do you control the model's weights?
Every major provider sells inference at roughly half price if you can wait up to 24 hours. The discount isn't the point — the contract is, and it tells you which agent work was never realtime to begin with.
You quantized the weights to 4-bit and thought memory was solved. At long context the KV cache dwarfs the weights — and it needs a different kind of quantization to shrink safely.
The three formats aren't competing for the same job — one buys you faster math, one buys you smaller weights, and one is the fallback for hardware that can't do the first. Know which bottleneck you're paying down.
The architecture decision underneath every agent framework is one most teams skip — and the math of compounding errors says the boring choice is usually right.
The embedding model you pick barely moves your bill. The dimensions you store and the precision you keep — that's the recurring cost, and it's the decision almost nobody makes on purpose.
They look like a difficulty ladder. They're three orthogonal axes — and only one of them measures the thing that decides whether your agent survives contact with real users.
A frontier model on every node is the default, not the optimum. Most agent calls are narrow, repetitive, and format-constrained — exactly the shape a small model was built for.
The three ways to align a model on preference data aren't a quality ladder — they're a pipeline being dismantled one component at a time. The thing each method removes tells you what it costs.
Dense, sparse, and late-interaction retrieval aren't a quality ladder. They're three answers to one question — where does the matching cost live — and the answer decides your storage bill.
For a voice agent, the number that decides the experience isn't audio quality or even the vendor's model latency. It's production time-to-first-audio — and the gap between the two is where the choice actually lives.
Three ways to compress embeddings for cheaper, faster retrieval — and the two-tier trick that turns a 32x memory cut into a 4% accuracy cost instead of a wipeout.
Tools that shrink a prompt by 2–20x before it hits the model promise a smaller token bill. Whether you actually save anything depends on a comparison nobody runs first — compression versus caching.
Between two spec revisions in 2025, MCP servers quietly stopped being their own authorization servers. The one parameter that change forces your client to send is the whole security story.
The three options differ by orders of magnitude in GPU memory — but the part that actually decides your result isn't the rank, and it isn't the quantization.
Buyers shop for these cards by peak FLOPS. Token generation barely uses them. The spec that actually moves inference throughput is the one most spec sheets bury — and a single NVIDIA card proves it.
Naive RAG retrieves once and hopes. Agentic RAG turns retrieval into a decision the model makes at runtime — paying for it on every query to win the queries that silently fail.
Million-token windows were supposed to kill retrieval. The benchmarks say something stranger — the choice is really between two different failure modes, and only one of them is loud.
All three clear the recall-and-latency bar for almost any agent you'll build. The real decision is where the operational cost lives — and there's a query volume where the answer flips.
Almost every vector-index comparison argues about query speed. Below ten million vectors that is the one thing that rarely decides it. The real choice is where your vectors live, and what it costs to change them.
They are not two answers to one question. RAG fixes what the model doesn't know; fine-tuning fixes what it won't do the way you need. Pick by the failure, not the fashion.
Prompt engineering optimized a string. Context engineering manages a finite, decaying budget — because the context window is not a bucket you fill, it is attention that rots as it fills.
The chunk-size A/B test is the most over-run experiment in RAG. The teams winning on retrieval stopped tuning how they split and started fixing what each chunk forgets.
Using a model to grade your model feels like measurement. Until you learn what the judge is actually rewarding — verbosity, position, and its own prose — it's closer to a focus group of one.