RAG gives the model an open book; fine-tuning makes it memorize. RAFT does the thing neither does — it trains the model on bad retrieval, so it survives the wrong chunk your production retriever will hand it.
Every LLM-tracing vendor now sells the same promise — open, portable, OTel-native. The schema that makes that true isn't finished, and there's an env var to prove it.
A reranker and a diversity step look like the same 'advanced RAG' upgrade. They fix opposite failures — and the benchmark that everyone cites quietly shows that turning on diversity often does nothing at all.
Mixture-of-Agents wins by quality, not by variety — and a careful 2025 replication found that aggregating repeated samples from your single best model beats mixing different ones in most cases. Here's when an ensemble actually pays, and when it just adds latency.
The 2026-07-28 spec made MCP stateless. Long-running work and statelessness are in direct tension — and the Tasks extension resolves it by handing the bookkeeping to the client. The tell is what got deleted.
The next Model Context Protocol release stops adding features to the core and starts subtracting them. The Extensions framework is how — and 'in the spec' no longer means 'in the core.'
Both kinds of cache hit read at the same discount, so cost-per-hit is the wrong thing to choose on. The real split is a guarantee you pay for versus a freebie you can't shape.
A JSON object isn't valid until its closing brace — but your UI shouldn't wait for it. The trick is realizing a streamed object is a view, not a value, and validating it exactly once: at the end.
The SDK's 10-minute default times out one call; an agent makes dozens. You need a deadline the whole loop shares — and cancelling to enforce it still costs tokens and can corrupt state.
An agent has no ROLLBACK: when step three fails, the first two already happened in the world. The fix is a compensating undo for every tool — and putting the one you can't undo last.
For an app built on a hosted LLM API, the wall you hit under load isn't the model's speed — it's the provider's rate limiter and your own retry policy. Test for the ceiling and the fall, not the throughput.
The try/except instinct that keeps a normal program alive is the one that kills an agent. A tool error isn't an exception to catch — it's the next message in the conversation, and where you put it decides whether the agent can recover.
A reranker can only reorder what your retriever already fetched, so the ceiling on its lift is your stage-one recall — measure that first, then judge the reranker as the latency and dollars you pay to convert recall into precision.
Your RAG pipeline works on documents and falls apart on a spreadsheet — because a table's meaning lives in its grid, and an embedding flattens the grid away.
The first rigorous benchmark of repository context files is in, and the answer is uncomfortable: the auto-generated ones make agents slightly worse, the hand-written ones barely help, and both raise your bill ~20%.
The two halves of every LLM request fight each other on the same GPU. Disaggregated serving splits them onto separate hardware — and the win is real, but only past a certain scale.
If your agent's reward is a number it can reach without doing the work, it will eventually reach the number without doing the work — and 2026's research says that habit doesn't stay contained.
Vercel's new agent framework treats an agent as a directory of files. LangGraph hands you a portable graph. The decision isn't the loop they run — it's who owns the production stack wrapped around it.
Trainium2 and Inferentia2 sell real price-performance and AWS capacity. NVIDIA sells CUDA. The decision is whether the Neuron SDK supports your model and serving stack — and how much engineering you'll spend finding out.
Prompt and semantic caches store the model's work and fail cheaply. Tool-result caching stores the world's — and it forces a question every agent codebase has dodged: which tools are safe to cache?
The same models that ace SWE-bench Verified collapse on its successor. The gap isn't difficulty — it's the size of an illusion, and the only durable fix turned out to be a software license.
Four ways to make an agent fix its own mistakes. Three of them quietly outsource the judgment to the world — and the one that doesn't is the one the research keeps catching in the act.
Builders keep wiring diarization into the live loop of a one-on-one voice agent. There, it solves a problem you don't have — because you already own one of the two voices.
Both pack weights into the same E2M1 four-bit float. The fight is entirely about the block scale — and that one design choice decides whether you keep your accuracy or hand it to the open standard.
Microsoft stopped shipping orchestration patterns and started shipping the runtime underneath them. The three Build 2026 launches are all below the framework — and one of them quietly retires the JSON tool-call loop.
The most common serious flaw in MCP servers isn't prompt injection. It's SSRF — the boring, pre-AI bug that sank Capital One — and we just installed it by the thousand.
The first official MCP extension lets a server ship an interactive interface into the chat, not just a string. The clever part is a flag that says who each result is for.
Reranking quietly split into three architectures in the last year. They make the same accuracy-for-latency trade in different places — and the newest, highest-scoring tier is the one you can least afford on a hot path.
Deep Agents isn't a fourth framework competing with LangChain and LangGraph — it's a preset of LangChain middleware on the same runtime. The choice is how much opinion you want pre-assembled.