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Claude Fable 5 vs Claude Opus 4.8

Claude Fable 5 grades higher overall (90.7 against 82.6). Claude Opus 4.8 costs 50% less for the same work, and both read a 1M-token context.

Claude Fable 5

by Anthropic · #3 of 67 overall

Coming soon · price at launch
Context
1M
Input / 1M
$10.00
Output / 1M
$50.00

Claude Opus 4.8

by Anthropic · #14 of 67 overall

Coming soon · price at launch
Context
1M
Input / 1M
$5.00
Output / 1M
$25.00

Better overall

Claude Fable 5

Grade 90.7 vs 82.6

Cheaper

Claude Opus 4.8

50% less, $10.00 vs $20.00 blended

Larger context

Same

1M vs 1M tokens

SWE-bench Verified

Claude Fable 5

95% vs 88.6%

Head to head

Public benchmarks. Longer is better; each value links to its source.

LMArena TextElo-style rating · LMArena (CC BY 4.0) · Oct 15, 2026
Claude Fable 5Claude Fable 5: 1,503
Claude Opus 4.8Claude Opus 4.8: 1,482
LMArena WebDevElo-style rating · LMArena (CC BY 4.0) · Oct 13, 2026
Claude Fable 5Claude Fable 5: 1,624
Claude Opus 4.8Claude Opus 4.8: 1,556
LMArena CodingElo-style rating · LMArena (CC BY 4.0) · Oct 15, 2026
Claude Fable 5Claude Fable 5: 1,551
Claude Opus 4.8Claude Opus 4.8: 1,534
SWE-bench Verified% of issues resolved · SWE-bench · Jun 9, 2026 · reference
Claude Fable 5Claude Fable 5: 95%v
SWE-Bench Pro% of tasks resolved · Scale AI SWE-Bench Pro · Jun 9, 2026 · reference
Claude Fable 5Claude Fable 5: 80%v
Terminal-Bench 2.1% of tasks passed · Terminal-Bench · Jun 9, 2026 · reference

Claude Fable 5Claude Opus 4.8v = reported by the model’s maker. — = no public score yet. Arena bars span the range across every model we grade.

What it costs you

Drag to match your monthly usage.

Claude Fable 5$4,000 /month
Claude Opus 4.8$2,000 /month

Claude Opus 4.8 saves you $2,000 a month at this usage, $24,000 a year.

At a glance

AttributeClaude Fable 5Claude Opus 4.8
Made byAnthropicAnthropic
AvailabilityComing soonComing soon
Overall gradeExcellent · 90.7Excellent · 82.6
Overall rank#3 of 67#14 of 67
Input price$10.00 per 1M$5.00 per 1M
Output price$50.00 per 1M$25.00 per 1M
Context window1,000,000 tokens1,000,000 tokens
Reasoning levelsYesYes
Reads imagesYesYes
Model IDclaude-fable-5claude-opus-4-8

Try both with one key

Same endpoint, same key, both hosted in the USA. Change one word to switch models, in Claude Code, Cursor, Cline or your own code.

Get your API key
# Ask either model the same thing
curl https://fullsendai.com/v1/chat/completions \
  -H "Authorization: Bearer $FULLSEND_API_KEY" \
  -d '{"model": "claude-fable-5", "messages": [...]}'

# …then swap one word
  -d '{"model": "claude-opus-4-8", "messages": [...]}'

Questions

Is Claude Fable 5 or Claude Opus 4.8 better?

Claude Fable 5 grades 90.7 against 82.6 for Claude Opus 4.8, from public benchmarks.

Which is cheaper, Claude Fable 5 or Claude Opus 4.8?

Claude Opus 4.8: $5.00 in and $25.00 out per million tokens, against $10.00 and $50.00 through FullsendAI.

Which has the larger context window?

Neither: both take 1,000,000 tokens.

Can I use both with one API key?

Yes, once they launch: both are coming soon, at the prices shown, and both will use the same FullsendAI key.

Model rankingsAll benchmarksCompare other models

Scores: LMArena (CC BY 4.0), SWE-bench, Scale AI SWE-Bench Pro, Terminal-Bench, and model makers’ published results where marked v. Prices are FullsendAI’s, per million tokens. Data as of Oct 28, 2026.