mobilegym: Skill for Claude Code

Designing bench_env Tasks

Overview

Rushing from "here's an App" to "here are 5 task classes" produces low-difficulty suites whose judge logic can't actually verify completion. Design must precede code.

Authoritative reference: bench_env/docs/task/TASK_AUTHORING_GUIDE.md (reading §1 + §2 once is required; this skill enforces its gates).

The Gate: two artifacts before any Python

Produce both as plain text in the conversation before writing any task class. If you catch yourself opening tasks.py / defs/<TaskName>.py, stop and produce them.

1. Functional audit table (TASK_AUTHORING_GUIDE §1.1–1.2)

A table with one row per distinct feature area. Columns:

| Page/feature | Source file(s) | User-visible actions | Observable state path |

You must actually read: manifest.ts, navigation.declaration.ts, data/defaults.json, state.ts, pages/*, and the suite's app.py accessor if it exists. No skipping "because the app looks simple."

2. Data sufficiency check (TASK_AUTHORING_GUIDE §1.3)

For every function you plan to parameterize, confirm defaults.json / state.ts provides ≥3 varied entries. If it doesn't, either propose expanding defaults, or drop parameterization for that function.

Per-task: 4 judge-predict questions

For each proposed task, answer in 1-2 lines each before writing code (this is the soundness/completeness audit later enforced by TASK_AUTHORING_GUIDE §2.7 "Reliability requirements"):

1. Agent 完全做对时，最终 state / answer 长什么样？
2. Agent 最常见的 1-2 种错误是什么？会不会被误判通过？（soundness）
3. 有没有合理完成任务的替代路径？会不会被误判失败？（completeness）
4. 有无边界情况导致正确答案不唯一、或判定证据不足？

If any answer surfaces a flaw (common: initial state already equals criteria; ground truth not unique; answer requires subjective judgement), iterate the design in text — do not defer the fix to code review.

Rationalization table — STOP and do the step

Excuse	Reality
"App is tiny, audit is overkill"	Audit surfaces the data gap so you can close it before writing code.
"Judge predict is slow, I'll see issues when coding"	Design bugs (init=goal, non-unique ground truth) are 10× cheaper to fix in text.
"These tasks are obvious, pre-sim is busywork"	A task obvious enough to skip pre-sim is obvious enough to answer the 4 questions in 30 seconds.
"I'll produce both artifacts and code in one pass"	Then when code inherits a design flaw, you've wasted the coding pass. Gate is gate.