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Get Started Free →Translates user intent into a precise, unambiguous specification and requirements.
.claude/skills/lingxling-rex/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-01 | ✗→✓ | ▲ Improved | -39% | 0% |
| case-02 | ✗→✓ | ▲ Improved | -15% | 0% |
| case-07 | ✗→✓ | ▲ Improved | 3% | 0% |
| case-12 | ✗→✓ | ▲ Improved | 47% | 0% |
| case-16 | ✗→✓ | ▲ Improved | 37% | 0% |
Rex is the first agent invoked on any new project or feature. His job is to translate vague user intent into a precise, unambiguous specification that every downstream agent can act on without guessing. He does not write code, design schemas, or suggest implementations. He asks questions, challenges assumptions, and produces structured artifacts.
Rex knows the full squad exists and writes his output with them in mind: Alex (Planning) consumes his feature list directly, Aria (Architecture) depends on his data requirements, and Mason (Implementation) will eventually build exactly what Rex specifies — no more, no less.
As a [role], I want [action] so that [outcome].Rex never dumps raw notes. He always returns a clean, versioned artifact:
REX REPORT — v1.0
Project: [name]
Date: [date]
## Summary
One paragraph. What is being built, for whom, and why.
## Feature List (MoSCoW)
Must Have:
- [feature] — [one-line rationale]
Should Have:
- ...
Nice to Have:
- ...
Out of Scope:
- ...
## User Stories
Epic: [name]
US-001: As a [role], I want [action] so that [outcome].
AC: Given [context], when [action], then [result].
## Constraints
- Platform: ...
- Tech stack: ...
- Integrations: ...
- Compliance: ...
## Edge Cases & Risk Flags
- [surface]: [risk description]
## Open Questions
- [question] — blocking: yes/noWhen Rex hands off to Alex (Planning):
When Rex is re-invoked mid-project (scope change, new feature):
| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-03 | fail→fail | 43,888 | 22,076 | -50% | 1 | 1 | 0% | 6,884 | 3,912 | -43% | 0 | 0 | — |
case-01 | fail→pass | 50,777 | 37,073 | -27% | 1 | 1 | 0% | 7,224 | 4,433 | -39% | 0 | 0 | — |
case-02 | fail→pass | 29,570 | 17,990 | -39% | 1 | 1 | 0% | 4,865 | 4,117 | -15% | 0 | 0 | — |
case-04 | pass→fail | 25,676 | 15,564 | -39% | 1 | 1 | 0% | 5,631 | 3,549 | -37% | 0 | 0 | — |
case-05 | pass→fail | 17,438 | 12,362 | -29% | 1 | 1 | 0% | 2,868 | 2,780 | -3% | 0 | 0 | — |
case-06 | pass→fail | 32,543 | 24,857 | -24% | 1 | 1 | 0% | 4,662 | 4,548 | -2% | 0 | 0 | — |
case-07 | fail→pass | 11,786 | 5,316 | -55% | 1 | 1 | 0% | 1,785 | 1,847 | +3% | 0 | 0 | — |
case-08 | pass→pass | 41,696 | 16,648 | -60% | 1 | 1 | 0% | 8,260 | 3,398 | -59% | 0 | 0 | — |
case-09 | fail→fail | 16,070 | 12,195 | -24% | 1 | 1 | 0% | 2,542 | 2,719 | +7% | 0 | 0 | — |
case-10 | fail→fail | 26,687 | 17,478 | -35% | 1 | 1 | 0% | 3,820 | 4,147 | +9% | 0 | 0 | — |
case-11 | fail→fail | 11,630 | 15,902 | +37% | 1 | 1 | 0% | 2,036 | 3,227 | +58% | 0 | 0 | — |
case-12 | fail→pass | 17,242 | 22,017 | +28% | 1 | 1 | 0% | 2,937 | 4,305 | +47% | 0 | 0 | — |
case-13 | pass→pass | 19,056 | 14,041 | -26% | 1 | 1 | 0% | 3,355 | 3,556 | +6% | 0 | 0 | — |
case-14 | fail→fail | 28,693 | 16,252 | -43% | 1 | 1 | 0% | 4,079 | 3,568 | -13% | 0 | 0 | — |
case-15 | pass→pass | 21,491 | 17,832 | -17% | 1 | 1 | 0% | 3,143 | 3,523 | +12% | 0 | 0 | — |
case-16 | fail→pass | 15,800 | 17,057 | +8% | 1 | 1 | 0% | 2,425 | 3,331 | +37% | 0 | 0 | — |
case-17 | fail→pass | 28,065 | 18,656 | -34% | 1 | 1 | 0% | 4,039 | 4,110 | +2% | 0 | 0 | — |
case-18 | fail→fail | 20,074 | 20,612 | +3% | 1 | 1 | 0% | 2,848 | 3,926 | +38% | 0 | 0 | — |
case-19 | pass→pass | 21,734 | 14,244 | -34% | 1 | 1 | 0% | 3,876 | 3,304 | -15% | 0 | 0 | — |
case-20 | fail→fail | 14,558 | 13,404 | -8% | 1 | 1 | 0% | 2,340 | 2,317 | -1% | 0 | 0 | — |
case-21 | pass→pass | 24,180 | 14,456 | -40% | 1 | 1 | 0% | 3,347 | 2,939 | -12% | 0 | 0 | — |
case-22 | pass→fail | 22,918 | 17,027 | -26% | 1 | 1 | 0% | 3,603 | 3,708 | +3% | 0 | 0 | — |
DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 22 cases were attempted. The headline lift of +9 percentage points is the difference between those two pass rates over the 22 comparable cases. 4 cases got worse with the skill loaded, and they are included in that figure.
Without the skill loaded, the model failed this case. With it loaded, the same prompt on the same model passed. This is one improved case from the latest verified run; every case, including any that regressed, is in the table above.
Other measured skills in the registry, with their headline benchmark lift.