You can't A/B test an agent the way you A/B test a button. The unit of variance is a trajectory, not a click — so the gate has to be offline, and "shadow mode" means something different than it does for a model.
Mem0 says 92.5% on LoCoMo. Mastra says 95% on LongMemEval. Zep corrected its own 84% to 58%. They can't all be right — and the baseline that beats them all is the one no vendor charts.
The MTEB leaderboard is a prior, not an oracle. The model that wins your RAG system is the one you measure on a few hundred of your own labeled queries — here is how to build that eval.
A deep research agent hands you a long, confident, well-structured report. Grading it means measuring two different things at once — how good it reads, and whether a single sentence is actually supported.
Write the eval before the prompt. The test suite you build first is the only thing that lets you change models next month without praying — and in 2026, you will change models.
Static benchmarks freeze the world while an agent thinks. Meta's GAIA2 lets time run — and the smartest model, GPT-5, turns out to be the one that misses deadlines.
An agent leaderboard that ranks only on accuracy is secretly ranking on willingness to spend. Add the cost axis and the board's #1 is often not even on the frontier.
Most agent benchmarks hand the whole task to the model. τ-bench keeps the user in the loop, and τ²-bench gives the user their own hands — which is where frontier agents quietly fall apart.
A new benchmark drops the same models from ~73% to ~25% — not by making the bugs harder, but by taking away the one thing SWE-bench always handed over: a map to the change.
Gartner says purpose-built agent software more than doubles to $206.5B this year. The same firm says 40%+ of agentic projects get canceled. Both numbers are true, and they're the same story.
The benchmarks for web-browsing agents split along a fault line the coding benchmarks never had — and the trick that makes one of them work quietly hides which half of your agent is actually good.
SWE-bench hands an agent a broken test and a healthy repo. Terminal-Bench hands it a live machine and lets it break things. That's why a top SWE-bench score tells you almost nothing about the second number.
The number on the spec sheet is a memory allocation, not a comprehension score. A needle test passing at 1M tokens tells you the model can find a string — not that it can use the context. Here's the benchmark that measures the difference.
Every provider now sells the same ~90% discount on repeated context. The number on the brochure is not where the bills actually diverge — three quieter terms are.
The number at the top of the MTEB leaderboard has quietly stopped meaning what you think it means. Here is which board to read, and why the newest one hides half its test set on purpose.
Decode is memory-bandwidth bound, so a GPU's TFLOPs barely predict serving capacity. What caps concurrency is the KV cache. Here's the actual arithmetic, with a worked example.
Every pricing model for an AI agent is really a decision about who absorbs the inference bill — and the floor under any outcome price is the cost of producing that outcome.
Bigger context windows don't fix forgetting. The benchmarks that actually test agent memory — LoCoMo and LongMemEval — and what their question categories reveal about where it breaks.
A single throughput figure is uninterpretable without the load that produced it and the prompt shape you fed in. The honest output of an LLM benchmark is a curve, and the number that matters is goodput — the most traffic you can serve while still meeting your latency SLO.
pass@k asks whether an agent can ever solve a task. pass^k asks whether it solves it every single time. For long-horizon agents those are different questions — and the gap is where production failures live.
A model that solves a task 61% of the time can be reliable only 25% of the time. The gap between those two numbers is where production agents go to die.
Learned sparse retrieval promises dense-quality matching without giving up the inverted index. The catch isn't relevance — it's the query-time bill, and there's a mode that erases it.
Flat top-k retrieval returns the chunks most similar to your query. For "what is this document about?" that's exactly the wrong thing. RAPTOR retrieves at the right altitude instead.
Three benchmarks, three verification methods, three very different definitions of 'success' — so a single computer-use percentage tells you almost nothing without the asterisks.
Decoder-only LLMs took all the oxygen, but the model quietly doing your retrieval, reranking, and classification is still a small bidirectional encoder — and in late 2024 it finally got a 2024-era redesign.
A year on, the data is in — almost nobody reads your llms.txt. The files that move the needle are the one that blocks crawlers and the content that earns a citation.
Your engine computes a KV cache, uses it once, and throws it away. Offloading turns that scratchpad into a shared storage tier — and changes the question you should be asking.
The way you start an agent — schedule, HTTP event, or message queue — decides its retry, durability, and concurrency behavior more than the framework you write it in does.
Storing embeddings at full precision is a tax most RAG systems don't need to pay. Binary cuts memory 32x — and the trick that buys the quality back is cheaper than the savings.
The eval-tooling field just split into three camps and lost two players to acquisition in a single month. Pick on philosophy and independence, not the feature grid.