| --- |
| license: mit |
| language: |
| - en |
| pretty_name: Webdev-Bench |
| size_categories: |
| - n<1K |
| tags: |
| - web-development |
| - frontend |
| - agent |
| - benchmark |
| - code-generation |
| --- |
| |
| # Webdev-Bench |
|
|
| Webdev-Bench measures an agent's ability to carry **real frontend development** through an |
| evolving application state: it builds an app from a natural-language product requirement, |
| then keeps modifying that same codebase across several rounds of requirements. |
|
|
| This repository contains the 40 composite tasks used in |
| [WebCoder: Scaling General Frontend Development with Artifact-Grounded Agentic Reinforcement |
| Learning](https://arxiv.org/abs/2610.23104). |
|
|
| ## What a task is |
|
|
| A composite task chains several operators (generate, restyle, interactionise, remove a |
| section, wire up data) over one evolving project. Each task is defined by `task.json`: |
|
|
| ```jsonc |
| { |
| "task_id": "c41", |
| "layer": "composite", |
| "seed_type": "prd", // prd | brownfield | replicate |
| "operators": ["generate", "restyle", "make interactive", "remove section", "wire up data"], |
| "difficulty": "challenging", // challenging | regular |
| "domain": "content & news", |
| "milestones": [ // requirements injected in order, one per round |
| {"operator": "generate", "request": "...natural-language request..."} |
| ], |
| "checklist": [ // hidden acceptance items, not shown to the model |
| {"id": "gen.channels.five", |
| "m": 1, // 1-based index into milestones |
| "dimension": "visual", // functional | coverage | interaction | visual | data |
| "w": 1.5, // item weight |
| "description": "...what must be observably true..."} |
| ], |
| "inject": null, // defect description for repair tasks |
| "repair": false // whether this task carries an injected defect |
| } |
| ``` |
|
|
| All task text in this release is in English. The tasks were authored and run in Chinese and |
| are published here in English translation; requirements are written in a product manager's |
| voice, and each `checklist` item states an observable property of the running application. |
| The metric values reported in the paper were produced with the original Chinese task |
| text. This translation preserves every task id, checklist item id, milestone index and item |
| weight, so grades recorded under the original text line up with these files item by item; |
| re-running the benchmark on a further retranslation may produce different numbers. |
|
|
| ## Composition |
|
|
| | | | |
| |---|---:| |
| | Tasks | 40 (all composite layer) | |
| | Milestones (requirements) | 188 (4–5 per task) | |
| | Checklist items | 1125 | |
| | Seed types | prd 20 · brownfield 11 · replicate 9 | |
| | Difficulty | challenging 25 · regular 15 | |
| | Item dimensions | functional 408 · visual 309 · interaction 299 · coverage 108 · data 1 | |
|
|
| Seeds: |
|
|
| * **prd** — start from nothing; the task specifies a product requirement. |
| * **brownfield** — start from an existing Vite + React project in `repo/`; the task |
| modifies it. |
| * **replicate** — reproduce a reference design; these tasks need the corresponding |
| reference image (see *Reference images* below). |
|
|
| ## Metrics |
|
|
| Each checklist item is graded 0–3 against the running application: |
|
|
| | grade | meaning | |
| |---:|---| |
| | 3 | fully satisfied: observable behaviour matches the item, no visible defect | |
| | 2 | mostly satisfied: core behaviour right, minor deviations in copy, styling or edge states | |
| | 1 | partially satisfied, or unstable | |
| | 0 | not implemented, or not usable | |
|
|
| Scores are computed **conjunctively per requirement**: a requirement (milestone) counts as |
| satisfied only when *all* checklist items under it reach grade 3. The main metric is |
|
|
| ``` |
| RS = (requirements fully satisfied) / (requirements) |
| ``` |
|
|
| with dimension slices computed the same way over the items of each dimension: |
|
|
| * **FS** — functional + coverage items |
| * **IS** — interaction items |
| * **VS** — visual items |
|
|
| **DSR** is the delivery success rate: the fraction of tasks whose `./start.sh` starts an |
| application that answers on port 3000. Undelivered tasks score 0 and stay in the |
| denominator. |
|
|
| Grading is done by a model-based verifier that operates the running app through a browser, |
| never by reading the candidate's source code. Item grades for individual runs are not |
| included in this release. |
|
|
| ## Evaluation protocol |
|
|
| The reference protocol (`v9_gated`) is multi-round: |
|
|
| 1. Inject requirement *k* and let the agent work in the same project state. |
| 2. Run a mechanical health check, then a gate check that looks at the rendered page and |
| decides whether the requirement is met. |
| 3. On failure, return one short user-voice feedback line and retry that requirement, up to |
| three times, within a per-task time pool. |
| 4. At the end, perform a full acceptance pass over every checklist item of every |
| milestone and compute the metrics from those final grades. |
|
|
| Because each requirement is a delta on the same evolving project, tasks cannot be |
| decomposed into independent single-turn problems. |
|
|
| ## Files |
|
|
| ``` |
| SUBSET40.txt the 40 task ids |
| tasks/<id>/task.json the task: milestones, checklist, metadata |
| tasks/<id>/repo/** seed project (brownfield tasks only, 11 tasks) |
| tasks/<id>/prototypes/repo_state.jpg |
| before screenshot of the seed project (11 tasks) |
| tasks/<id>/prototypes/reference.jpg |
| reference design image (9 replicate tasks) |
| ``` |
|
|
| ## Reference images |
|
|
| Nine tasks, all of `replicate` seed type, depend on a reference design image. It is stored |
| at `tasks/<id>/prototypes/reference.jpg` and referenced from `task.json` by the relative |
| path `seed_meta.ref_image_src`. |
|
|
| These reference images are long screenshots of **real third-party websites**, captured for |
| research on design reproduction. They are included so that the tasks can be run as intended, |
| but they are **not covered by the MIT license of this repository**: the rights remain with |
| the respective site owners, and the images are provided for research and benchmarking only, |
| without any permission to reuse them commercially or in derivative works. If you are a |
| rights holder and want an image removed, contact the authors and it will be taken down. |
|
|
| ## License |
|
|
| Task definitions (`task.json`), seed projects (`repo/**`) and the seed-project screenshots |
| (`repo_state.jpg`) are released under the MIT License. The reference design images |
| (`reference.jpg`) are third-party material and are excluded from that license, as described |
| under *Reference images*. |
|
|
| The seed projects are small Vite + React applications assembled for these tasks and contain |
| bundled image assets used as placeholder art. |
|
|
| ## Citation |
|
|
| ```bibtex |
| @article{dou2026webcoder, |
| title = {WebCoder: Scaling General Frontend Development with Artifact-Grounded Agentic Reinforcement Learning}, |
| author = {Dou, Zijun and Yang, Zhen and Liu, Xijun and Zhou, Dongzhuoran and Zeng, Aohan and Tang, Jie}, |
| journal = {arXiv preprint arXiv:2610.23104}, |
| year = {2026} |
| } |
| ``` |
|
|
