Grok 4.6 vs Claude Fable 5

head-to-head

what do the benchmarks actually say?

On SWE-bench Verified — real, human-validated GitHub issues resolved end-to-end — Grok 4.6 posts 95.6% against 95.0% for Claude Fable 5, a 0.6-point gap. Verified is the closest public proxy for "can it fix a real bug in a real repo without help", which is why it anchors our ranking.

A few points either way is real but not decisive: within that band, the agent scaffolding around the model — how it retrieves files, runs tests, and retries — often matters as much as the base model. Treat the gap as a lean, not a verdict.

which is cheaper to run?

Grok 4.6 is the cheaper model: $2 per 1M input tokens ($6 output) versus $10 ($50 output) for Claude Fable 5 — roughly 5× less on input. Coding workloads are output-heavy — agents write diffs, tests and retries — so weight the output rate more than the input rate when you estimate a monthly bill.

when to pick each

how were these scores verified?

We only print a number once it's confirmed against a primary source or an independent evaluation, and each row on our leaderboard records which kind it is:

• Grok 4.6: Independent (vals.ai, benchmark updated 2026-08-12, mini-swe-agent bash-only harness): SWE-bench Verified 95.60% ±0.92. Entered ranked 2026-08-13, one day after launch, and it enters near the top: 4th of the 82 systems vals.ai has run, behind Claude Opus 5 (97.00% ±0.76), DeepSeek V4 Pro 0813 (96.40% ±0.83) and GPT-5.6 Sol (96.20% ±0.86). Read the gap to Claude Fable 5 below it (95.00% ±0.98) as a tie: 0.6 points against a pooled SEM of about 1.34 is well inside the margin of error, and we rank Grok 4.6 higher only because it scored higher. Same against Sol above it, a 0.6-point gap. This is the second time running that xAI shipped a Grok with no SWE-bench Verified number of its own and vals.ai supplied one: Grok 4.5 waited nine days, Grok 4.6 waited one. SpaceXAI still publishes no SWE-bench Verified or SWE-bench Pro figure, so the ranked score here is entirely vals.ai's measurement with no vendor claim to disclose against. What xAI did publish, all vendor-reported on its own table: AA Intelligence Index 61, CursorBench v3.2 69.9%, DeepSWE v1.1 65.9%, FrontierCode v1.1 Extended 61.3%, APEX-Agents 57.5%, APEX-SWE 56.4%, Terminal-Bench v3.0 26%, GDPVal-AA v2 1753, AA-Briefcase 1577, Harvey LAB (Vals) 15.8%. That table's shape still holds and is worth reading against this score: Grok 4.6 takes the best result on the three knowledge-work evals and loses the two hardest agentic-coding ones by wide margins (DeepSWE 65.9% vs Sol's 73%, Terminal-Bench v3.0 26% vs Sol's 34.6%). Terminal-Bench v3.0 is NOT comparable to the 83.3% TB2.1 figure on the Grok 4.5 row: on v3.0 Grok 4.5 scores 15.7% and the whole field tops out near 34%. On cost it is the standout of the top five, $0.78 per test against $1.29 for Opus 5, $1.15 for Sol and $2.05 for Fable 5, though it is also the slowest of them at 604s. Pricing unchanged from Grok 4.5 at $2/$6 per 1M. See /p/grok-4-6-frontier-benchmarks-terminal-bench-gap/.
• Claude Fable 5: Independent (vals.ai, Jul 14 2026, mini-swe-agent bash-only harness): SWE-bench Verified 95.00% ±0.98. Held the top score until GPT-5.6 Sol was evaluated at 96.20% ±0.86, and now sits third behind Claude Opus 5 (97.00% ±0.76, added Jul 25 2026). All three are within the combined margin of error of each other. Against Sol it is a 1.2-point gap — a 1.2-point gap that is inside the combined margin of error (~0.9 sigma), so the two are a statistical tie and we rank Sol first only because it scored higher. Re-confirmed 2026-08-13: vals.ai still measures 95.00% ±0.98, unchanged, and Grok 4.6 has since entered above it at 95.60% ±0.92, a 0.6-point gap that is inside the combined margin of error and should be read as a tie. SWE-bench Pro 80.3% uses Anthropic's own scaffolding and is contested. Restored Jul 1, 2026 after a 20-day export-control suspension. Pricing $10/$50 per 1M.

Full reviewsGrok 4.6, decodedClaude Fable 5, decoded

Ranked on our AI Coding Leaderboard, updated 2026-08-13. Scores are confirmed against primary sources; prices are per 1M input tokens and can change.