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Get Started Free →Interface with Codeforces API for contest data, problem sets, and submissions
.claude/skills/a5c-ai-codeforces-api-client/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-01 | ✗→✓ | ▲ Improved | -13% | 0% |
| case-02 | ✗→✓ | ▲ Improved | -11% | 0% |
| case-03 | ✗→✓ | ▲ Improved | -52% | 0% |
| case-04 | ✗→✓ | ▲ Improved | -52% | 0% |
| case-05 | ✗→✓ | ▲ Improved | -9% | 0% |
Interface with the Codeforces API to fetch contest data, problem sets, submissions, and user statistics for competitive programming workflows.
Uses the official Codeforces API (https://codeforces.com/apiHelp) with proper rate limiting and authentication when required.
json{ "type": "object", "properties": { "action": { "type": "string", "enum": ["getContestProblems", "getUserSubmissions", "getProblemset", "getStandings", "getUserRating"] }, "contestId": { "type": "integer" }, "handle": { "type": "string" }, "tags": { "type": "array", "items": { "type": "string" } }, "count": { "type": "integer", "default": 10 } }, "required": ["action"] }
json{ "type": "object", "properties": { "success": { "type": "boolean" }, "data": { "type": "object" }, "error": { "type": "string" } }, "required": ["success"] }
javascript{ "action": "getContestProblems", "contestId": 1900 }
| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-01 | fail→pass | 20,701 | 11,898 | -43% | 1 | 1 | 0% | 3,666 | 3,207 | -13% | 0 | 0 | — |
case-02 | fail→pass | 7,379 | 5,315 | -28% | 1 | 1 | 0% | 1,814 | 1,613 | -11% | 0 | 0 | — |
case-03 | fail→pass | 8,230 | 2,193 | -73% | 1 | 1 | 0% | 1,626 | 788 | -52% | 0 | 0 | — |
case-04 | fail→pass | 10,977 | 2,451 | -78% | 1 | 1 | 0% | 1,764 | 838 | -52% | 0 | 0 | — |
case-05 | fail→pass | 4,183 | 2,250 | -46% | 1 | 1 | 0% | 838 | 764 | -9% | 0 | 0 | — |
case-06 | fail→pass | 4,928 | 2,156 | -56% | 1 | 1 | 0% | 882 | 713 | -19% | 0 | 0 | — |
case-07 | fail→pass | 2,806 | 2,626 | -6% | 1 | 1 | 0% | 537 | 874 | +63% | 0 | 0 | — |
case-08 | fail→pass | 4,419 | 2,007 | -55% | 1 | 1 | 0% | 778 | 748 | -4% | 0 | 0 | — |
case-09 | fail→pass | 8,843 | 6,991 | -21% | 1 | 1 | 0% | 1,957 | 1,990 | +2% | 0 | 0 | — |
case-10 | fail→fail | 6,674 | 4,768 | -29% | 1 | 1 | 0% | 1,427 | 1,406 | -1% | 0 | 0 | — |
case-11 | fail→pass | 7,561 | 2,005 | -73% | 1 | 1 | 0% | 1,329 | 803 | -40% | 0 | 0 | — |
case-12 | fail→pass | 5,741 | 2,128 | -63% | 1 | 1 | 0% | 1,098 | 734 | -33% | 0 | 0 | — |
case-13 | fail→pass | 3,879 | 2,829 | -27% | 1 | 1 | 0% | 648 | 924 | +43% | 0 | 0 | — |
case-14 | fail→pass | 2,773 | 2,063 | -26% | 1 | 1 | 0% | 479 | 700 | +46% | 0 | 0 | — |
case-15 | fail→pass | 5,577 | 1,964 | -65% | 1 | 1 | 0% | 1,073 | 743 | -31% | 0 | 0 | — |
case-16 | fail→pass | 3,442 | 2,532 | -26% | 1 | 1 | 0% | 763 | 784 | +3% | 0 | 0 | — |
case-17 | fail→pass | 8,260 | 2,355 | -71% | 1 | 1 | 0% | 1,442 | 798 | -45% | 0 | 0 | — |
case-18 | fail→pass | 9,511 | 7,404 | -22% | 1 | 1 | 0% | 2,011 | 2,175 | +8% | 0 | 0 | — |
case-19 | fail→pass | 2,980 | 1,661 | -44% | 1 | 1 | 0% | 540 | 709 | +31% | 0 | 0 | — |
case-20 | fail→fail | 11,241 | 8,345 | -26% | 1 | 1 | 0% | 2,640 | 2,135 | -19% | 0 | 0 | — |
case-21 | fail→fail | 13,343 | 12,890 | -3% | 1 | 1 | 0% | 2,542 | 3,028 | +19% | 0 | 0 | — |
case-22 | fail→fail | 13,971 | 8,905 | -36% | 1 | 1 | 0% | 2,193 | 2,148 | -2% | 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 +82 percentage points is the difference between those two pass rates over the 22 comparable cases.
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.