KeyoAPI
Claude Fable 5 API — Flagship Chat & Agents
Claude Fable 5 is a flagship chat and agent model available through KeyoAPI’s OpenAI-compatible gateway.
Overview
Claude Fable 5 is a flagship chat and agent model available through KeyoAPI’s OpenAI-compatible gateway. Teams evaluating claude api pricing often need a single place to buy capacity for Claude-class and GPT-class models—exactly what an AI API relay provides. Use this page to understand positioning, pricing shape, and integration steps. Fable 5 suits product assistants, coding copilots, and knowledge agents that outgrow lightweight models. On KeyoAPI it shares authentication and metering with vision and speech endpoints, reducing procurement friction for startups. Indicative Keyo sell rates are about $8.82 input and $44.12 output per 1M tokens—confirm on /pricing/claude-fable-5. Official Anthropic flagship bands are often higher on list price; /compare shows the savings narrative for finance stakeholders. Combine with gpt-5.6-luna for bulk classification to keep blended cost down. B2B SaaS embeds Fable 5 for complex workflow automation. Agencies run client research agents overnight. Platform companies expose “bring your own prompt” features while metering on Keyo. Pair with Unlimited-OCR when users paste screenshots into chat. OpenAI-compatible chat completions with model=claude-fable-5. Enable streaming if your UI expects tokens ASAP. Create a key at /pricing/claude-fable-5. Fable 5 is the flagship Claude-class default when Sonnet stalls on hard agent loops, still purchased through the same OpenAI-compatible chat completions path. When you evaluate Claude API pricing as a SaaS founder, the hidden cost is usually not the first million tokens—it is the long tail of agent retries, tool loops, and failed plans. Fable 5 on KeyoAPI lets you keep those loops on a Claude-class model while Luna or Sonnet absorb cheap classification. Write eval harnesses that score planner quality separately from executor quality so you know when Fable is worth the uplift. Log prompt tokens, completion tokens, and tool-call counts per session; finance will ask for that breakdown before approving volume. For SDK migration, keep your existing OpenAI client, set baseURL to https://www.keyoapi.xyz/v1, and only change the model string. That is the whole point of an AI API relay: capability switching without a second SDK.
Quick start
Base URL: https://www.keyoapi.xyz/v1
Endpoint: POST /v1/chat/completions
Model: model=claude-fable-5
curl https://www.keyoapi.xyz/v1/chat/completions \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"claude-fable-5","messages":[{"role":"user","content":"Hello from KeyoAPI"}]}'Auth uses the same Bearer API key as chat. Full notes: Keyo docs.
FAQ
How does Keyo Claude pricing compare to Anthropic?
KeyoAPI aims to undercut official list pricing for comparable Claude-class tiers. Use /compare for side-by-side AI API price comparison numbers.
Can I keep my OpenAI SDK?
Yes. Change baseURL to https://www.keyoapi.xyz/v1 and set model to claude-fable-5.
Fable 5 vs Opus 5 vs Sonnet 5?
Fable targets flagship chat/agents; Opus emphasizes hard agent/coding; Sonnet balances cost and quality for everyday production traffic.