{"uid":"cap_bToRvrQZfYgiH-I6dm8EH","slug":"singit-ask-claude-haiku-5-5-e0606509","name":"SingIt Ask: Claude Haiku 5.5","description":"SingIt Ask: Claude Haiku 5.5 (Anthropic) chat completions with no API key or account, OpenAI-compatible. Anthropic's smallest, fastest Claude model: quick, low-latency answers. Call it when an agent needs Claude Haiku 5.5 specifically.","url":"https://ask.singitai.app/v1/chat/claude-haiku-5.5?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"model":{"type":"string","examples":["deepseek-v4.1-flash","claude-opus-5.5","gpt-5.5","gemini-3.1-pro"],"description":"Any model id from GET /v1/models; the ceiling follows its price. Omit for the default model."},"stream":{"enum":[false],"type":"boolean","description":"Streaming is not offered."},"messages":{"type":"array","items":{"type":"object","required":["role","content"],"properties":{"role":{"enum":["system","user","assistant"],"type":"string"},"content":{"type":"string","description":"Plain text; all messages together under 24000 characters."}}},"maxItems":40,"minItems":1,"description":"The conversation, oldest first."},"max_tokens":{"type":"integer","default":800,"maximum":1200,"minimum":1,"description":"The longest answer, in tokens. The payment ceiling grows with it; the charge follows what was used."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.0015","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.0015/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0015","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0015","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_hsRAmB_4PJUGOZEGTe3bo","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.0015","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Chat completions using Anthropic's Claude Haiku 5.5 model, accessible with no API key via per-call USDC payment over x402","exampleAgentPrompt":"Ask Claude Haiku 5.5 this question and keep the answer under 300 tokens: 'What are three practical tips for writing cleaner Python code?'","exampleUseCases":[{"title":"Fast agent reasoning step","prompt":"Use Claude Haiku 5.5 to quickly classify this customer support message as a billing issue, technical issue, or general inquiry, max 100 tokens: 'My invoice shows a charge I don't recognize from last Tuesday.'"},{"title":"Lightweight AI assistant reply","prompt":"Have Claude Haiku 5.5 answer this in under 200 tokens: 'Explain the difference between a mutex and a semaphore in simple terms.'"},{"title":"Multi-turn chat conversation","prompt":"Run a two-turn conversation through Claude Haiku 5.5 where I first say 'I want to learn Spanish in 3 months' and then ask 'What's the single most important habit to build?' — keep the final response under 400 tokens."}],"resultDescription":"A JSON chat completion response in OpenAI-compatible format containing the assistant's text reply, with usage statistics reflecting actual tokens consumed. Streaming is not supported; the full response is returned at once. Max response length is capped at 1200 tokens.","failureModes":["Payment not received or insufficient USDC balance — 402 Payment Required","Message content exceeds 24000 character combined limit — 400 Bad Request","max_tokens value outside allowed range of 1-1200 — 400 validation error","Upstream Anthropic API unavailability — 502 or 503 error","Malformed messages array (missing role or content) — 400 Bad Request"],"whenToPreferThis":"Choose this endpoint when you specifically need Anthropic's Claude Haiku 5.5 model — Anthropic's smallest and fastest Claude — and want minimal latency without managing an Anthropic account or API key. It is ideal for high-frequency agent reasoning steps, quick classification tasks, or lightweight chat where cost per call matters and you can pay per-use in USDC via x402. Prefer it over sibling endpoints when Claude's safety characteristics and Anthropic's training approach are important, but a smaller/faster model suffices over Claude Opus or Sonnet.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T19:05:29.650Z","isFirstParty":false,"canonicalSlug":"singit-ask-claude-haiku-5-5-e0606509"}