Terminal-Bench 2.1terminalregular expressionsJSONPython
Generate legal chess positions with regex substitutions
Encode a complete white move generator as ordered regex replacements that transforms FEN into every legal successor position.
regex-chess
Normalized profile
What this task asks for
Encode a complete white move generator as ordered regex replacements that transforms FEN into every legal successor position. Support castling with rights tracking, en passant, and queen-only promotion. Handle only white-to-move inputs. Emit every legal next FEN through the supplied re.sub loop. Stay below 100,000 pairs and 10MB.
Intent
- feature implementation
Work surfaces
- move generator
- position notation
Technology
- regular expressions
- chess
- FEN
- JSON
Expected artifacts
- /app/re.json
What makes it difficult
- quantitative performance, accuracy, or resource constraints
- specialized algorithmic or domain reasoning
- cross-language or cross-format integration
Published evidence
Model × harness outcomes
Counts are tied to these exact configurations. Harnesses are not treated as equivalent across benchmarks.
- Models
- 13
- Configurations
- 20
- Trials
- 101
Showing 20 of 20 configurations
| Model | Harness | Effort | Result | Passes |
|---|---|---|---|---|
| claude-fable-5anthropic · 2026-06-07 | claude-code2.1.167 | xhigh | All passed | 5/5 |
| claude-fable-5anthropic · 2026-06-05 | terminus-22.0.0 | high | Mixed4 errors | 1/5 |
| claude-opus-4-7anthropic · 2026-05-01 | claude-code2.1.123 | max | No passes6 errors | 0/6 |
| claude-opus-4-7anthropic · 2026-05-01 | terminus-22.0.0 | max | No passes5 errors | 0/5 |
| claude-opus-4-8anthropic · 2026-07-09 | claude-code2.1.205 | high | Mixed4 errors | 1/5 |
| claude-sonnet-5anthropic · 2026-07-09 | claude-code2.1.205 | high | Mixed2 errors · 1 disqualified | 2/5 |
| gemini-3-pro-previewgemini · 2026-05-01 | gemini-cli0.40.0 | high | Mixed | 1/5 |
| gemini-3-pro-previewgemini · 2026-05-01 | terminus-22.0.0 | high | Mixed | 3/5 |
| gemini-3.1-pro-previewgemini · 2026-05-05 | gemini-cli0.40.0 | high | Mixed | 2/5 |
| gemini-3.1-pro-previewgemini · 2026-05-05 | terminus-22.0.0 | high | Mixed | 2/5 |
| glm-5.1zai · 2026-05-01 | claude-code2.1.123 | max | No passes5 errors | 0/5 |
| gpt-5.5openai · 2026-05-01 | codex0.125.0 | xhigh | All passed | 5/5 |
| gpt-5.5openai · 2026-05-01 | terminus-22.0.0 | xhigh | All passed | 5/5 |
| gpt-5.6-lunaopenai · 2026-07-10 | codex0.144.0 | max | Mixed | 4/5 |
| gpt-5.6-lunaopenai · 2026-07-11 | codex0.144.1 | max | Mixed | 4/5 |
| gpt-5.6-solopenai · 2026-07-10 | codex0.144.0 | max | All passed | 5/5 |
| gpt-5.6-terraopenai · 2026-07-10 | codex0.144.0 | max | Mixed | 4/5 |
| gpt-5.6-terraopenai · 2026-07-11 | codex0.144.1 | max | All passed | 5/5 |
| grok-4.5cursor · 2026-07-09 | cursor-cli2026.07.08-0c04a8a | default | Mixed4 disqualified | 1/5 |
| muse-spark-1.1openai · 2026-07-09 | mini-swe-agent2.4.5 | xhigh | Mixed4 errors | 1/5 |