Claude Fable 5 vs K2 Think V2
Wins 5 of 6 areas
Coding · Agents · Reasoning · Facts · Long documents
Wins 0 of 6 areas
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Claude Fable 5 is the stronger all-rounder.
Scores updated · 17 tests both models report · How we compare
Where each one wins
Tests won in each of the six areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software30Claude Fable 53 of 3 tests
- ReasoningHard problems that need careful thinking30Claude Fable 53 of 3 tests
- AgentsCarrying out multi-step tasks on its own20Claude Fable 52 of 2 tests
- FactsGetting facts right instead of making them up20Claude Fable 52 of 2 tests
- Long documentsFinding answers in very long texts10Claude Fable 51 of 1 test
- Following instructionsDoing exactly what it is asked00Even0 each · 1 tie
Long documents and following instructions rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Fable 5 pulls ahead
- Command-line tasks in a real terminalTerminal-Bench 2.1+69.6points ahead
- Hard command-line tasks in a real terminalTerminal-Bench Hard+56.1points ahead
- Answers hard knowledge questions correctlyAA-Omniscience · Accuracy+47.4points ahead
Where K2 Think V2 pulls ahead
No clear win on a test scored out of 100.
Every test, side by side
All 17 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Fable 5
- Terminal-Bench 2.1Claude Fable 5 by 69.684.615+69.6
- Terminal-Bench HardClaude Fable 5 by 56.162.96.8+56.1
- SciCodeClaude Fable 5 by 286133+28
AgentsClaude Fable 5
- GDPValClaude Fable 5 by 55.655.60+55.6
- τ-Bench V3 · BankingClaude Fable 5 by 32.738.15.4+32.7
ReasoningClaude Fable 5
- Humanity's Last ExamClaude Fable 5 by 45.455.510.1+45.4
- CritPtClaude Fable 5 by 28.628.60+28.6
- GPQA DiamondClaude Fable 5 by 21.392.671.3+21.3
FactsClaude Fable 5
- AA-Omniscience · AccuracyClaude Fable 5 by 47.465.318+47.4
- AA-Omniscience · Non-hallucinationClaude Fable 5 by 7.636.428.8+7.6
Other results5 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- AA-OmniscienceClaude Fable 5 by 83.643.3-40.3+83.6
- τ²-Bench Telecom (AA run)Claude Fable 5 by 73.198.525.4+73.1
- Artificial Analysis Coding IndexClaude Fable 5 by 55.576.521+55.5
- AA Agentic IndexClaude Fable 5 by 49.2511.8+49.2
- AA IntelligenceClaude Fable 5 by 38.149.611.5+38.1
Questions people ask
Which is better, Claude Fable 5 or K2 Think V2?
Claude Fable 5 wins five of the six areas where both have results: coding, agents, reasoning, facts and long documents. K2 Think V2 wins none. They are level on following instructions.
Which is better for coding?
Claude Fable 5. It wins 3 of the 3 coding tests both models report; K2 Think V2 wins none.
How do you compare the two?
We use the 17 benchmark tests both models have published scores on. The verdict counts the 12 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 5 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.