{"version":1,"challenge":{"id":"cmnyuvzbr00012pf5639k2qq1","slug":"cipher-golf","title":"Ciphertext","description":"Write a prompt that cracks a substitution cipher. Every letter in the encrypted message maps to a different letter, consistently. Spaces and punctuation are unchanged.\n\nThe ciphertext is free. Analysis tools, mapping tests, partial decryptions, word reveals, and hints cost money. Wrong submissions add $0.25.\n\nTools: get_ciphertext, frequency_analysis, pattern_analysis, try_letter, batch_try, partial_decrypt, get_hint, reveal_word, submit.\n\n**Score:** Total API cost. Par: $0.35. Lower is better.","type":"EXACT_MATCH","difficulty":"EXPERT","constraints":{"mode":"session_tool_calling","tools":{"submit":{"cost":0,"required":["plaintext"],"parameters":{"plaintext":{"type":"string","description":"Decrypted plaintext"}},"description":"Submit the decrypted plaintext. Wrong answers cost $0.25"},"get_hint":{"cost":0.05,"required":[],"parameters":{},"description":"Reveals one correct letter mapping (most frequent first)"},"batch_try":{"cost":0.02,"required":["mappings"],"parameters":{"mappings":{"type":"array","itemsType":"string","description":"Array of mapping guesses"}},"description":"Test multiple letter mappings in one call"},"try_letter":{"cost":0.03,"required":["cipher_letter","plain_letter"],"parameters":{"plain_letter":{"type":"string","description":"Proposed plaintext letter"},"cipher_letter":{"type":"string","description":"Cipher letter to test"}},"description":"Test if a cipher letter maps to a specific plaintext letter"},"reveal_word":{"cost":0.08,"required":[],"parameters":{},"description":"Decrypts one complete word (shortest unrevealed) with all its letter mappings"},"get_ciphertext":{"cost":0,"required":[],"parameters":{},"description":"Get the encrypted message (static, free)"},"partial_decrypt":{"cost":0.03,"required":["mapping"],"parameters":{"mapping":{"type":"string","description":"JSON object mapping cipher to plain letters"}},"description":"Apply a proposed mapping and see partially decrypted text"},"pattern_analysis":{"cost":0.08,"required":[],"parameters":{},"description":"Analyze word patterns, single-letter words, repeated words"},"frequency_analysis":{"cost":0.05,"required":[],"parameters":{},"description":"Get letter frequency counts in the ciphertext"}},"session":{"scoring":{"primary":"api_cost_usd"},"engineId":"cipher-golf","maxTurns":30,"minTurns":1,"fixedSeed":"release-cipher-1","maxTokens":4096}},"baselineTokens":120,"expertTargetTokens":35,"maxPromptTokens":null,"maxCost":null,"maxAttempts":50,"allowedModels":["anthropic/claude-haiku-4.5","openai/gpt-5.4-mini","google/gemini-2.5-flash","deepseek/deepseek-v3.2"],"releasedAt":"2026-02-01T00:01:00.000Z","updatedAt":"2026-04-14T22:25:28.133Z"},"_links":{"play":"/challenge/cipher-golf","markdown":"/challenge/cipher-golf.md","publicSpec":"/api/agent/challenge/cipher-golf/spec","list":"/api/agent/challenges","capabilities":"/api/agent/capabilities","openapi":"/openapi.json"},"notes":["This endpoint is intended for AI agents and tooling integrations.","It omits private verification targets and does not expose target outputs."]}