compare/Claude Fable 5vsClaude Opus 4.8

Claude Fable 5 vs Claude Opus 4.8

Pricing, context window, capabilities, and release date — pulled from each provider's public docs. Both are available via the same AIgateway OpenAI-compatible endpoint; flip the model string to switch.

RUN BOTH LIVE

Paste a prompt. Watch them race.

Both models stream in parallel through your own AIgateway key. Tokens, latency, and cost update as they arrive.

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 Claude Fable 5
anthropic/claude-fable-5
Claude Opus 4.8
anthropic/claude-opus-4.8
ProviderAnthropicAnthropic
FamilyClaude 4
Modalitytexttext
Context window1,000,000 tok1,000,000 tok
Max output128,000 tok128,000 tok
Released2026-06-092026-05-28
Input price$10.00 /1M$5.00 /1M
Output price$50.00 /1M$25.00 /1M
Cache read$0.500 /1M
Toolsyesyes
Streamingyesyes
Visionyesyes
JSON modeyesyes
Reasoningyes
Prompt cachingyes
Claude Fable 5
anthropic/claude-fable-5
Full spec →

Claude Fable 5 is Anthropic's most capable widely released model, built for the most demanding reasoning and long-horizon agentic work. Adaptive thinking is always on, and the model supports a 1M token context window with up to 128k output tokens per request.

Strengths
  • General-purpose chat
  • Long context
  • Tool use
Claude Opus 4.8
anthropic/claude-opus-4.8
Full spec →

Claude Opus 4.8 is Anthropic's most capable generally available model, with a step-change improvement in agentic coding over Claude Opus 4.7. It uses adaptive thinking to calibrate reasoning per task and supports a one million token context window at standard pricing.

Strengths
  • Anthropic's most capable model — #1 on the Artificial Analysis Intelligence Index
  • Best computer-use / browser agent tested (84% on Online-Mind2Web)
  • Adaptive thinking — calibrates reasoning depth per task
  • ~4× less likely than Opus 4.7 to let code flaws pass unremarked
  • More efficient tool calling — fewer steps for the same result
SWITCH BETWEEN THEM

One key, both models, one line different.

# pip install aigateway-py openai
# aigateway-py: sub-accounts, evals, replays, jobs, webhook verify.
# openai SDK: chat/embeddings/images/audio — drop-in compat per our SDK's own guidance.
from openai import OpenAI

client = OpenAI(
    base_url="https://api.aigateway.sh/v1",
    api_key="sk-aig-...",
)

# Try Claude Fable 5
client.chat.completions.create(
    model="anthropic/claude-fable-5",
    messages=[{"role":"user","content":"hello"}],
)

# Try Claude Opus 4.8 — same client, same key
client.chat.completions.create(
    model="anthropic/claude-opus-4.8",
    messages=[{"role":"user","content":"hello"}],
)
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