Claude Sonnet 4.6 vs Grok 4.1 Fast

Summary of our 12-test head-to-head (scores are from our testing unless noted):

• Wins for Claude Sonnet 4.6: creative_problem_solving 5 vs 4 (Sonnet tied for 1st of 54), tool_calling 5 vs 4 (Sonnet tied for 1st of 54), safety_calibration 5 vs 1 (Sonnet tied for 1st of 55; Grok ranks 32/55), agentic_planning 5 vs 4 (Sonnet tied for 1st of 54). These differences matter for iterative development, agent orchestration, and public-facing apps where refusal/permission behavior and reliable function selection are critical.
• Wins for Grok 4.1 Fast: structured_output 5 vs 4 (Grok tied for 1st of 54) and constrained_rewriting 4 vs 3 (Grok rank 6 of 53). That means Grok is better at strict JSON/schema compliance and aggressive compression within character-limited outputs.
• Ties (no clear winner): strategic_analysis 5/5, faithfulness 5/5, classification 4/4, long_context 5/5, persona_consistency 5/5, multilingual 5/5. For long-context retrieval, multilingual parity, and baseline faithfulness, both models perform at top-tier levels in our tests.
• External benchmarks (supplementary): Beyond our internal suite, Claude Sonnet 4.6 scores 75.2% on SWE-bench Verified and 85.8% on AIME 2025 (Epoch AI), which supports its strengths in coding/problem-solving; Grok has no external scores in the payload. Practical meaning: Sonnet is the safer, more agent-capable option (tool selection, failure recovery, refusal behavior). Grok is the efficient, lower-cost choice for strict-format outputs and space-constrained rewriting, and it retains top-tier long-context and multilingual performance.

Raw unit costs: Claude Sonnet 4.6 charges $3 per 1K input tokens and $15 per 1K output tokens; Grok 4.1 Fast charges $0.20 per 1K input and $0.50 per 1K output. If you assume 1M input + 1M output tokens/month, Sonnet costs $18.00 (3+15) and Grok costs $0.70 (0.2+0.5). Scale: 10M in+out → Sonnet $180, Grok $7; 100M in+out → Sonnet $1,800, Grok $70. The ~30× price ratio (priceRatio: 30) means Sonnet is reasonable for low-to-moderate volumes or mission-critical flows where its higher scores matter; Grok is the clear choice for high-volume chat, support, or ingestion pipelines where cost dominates.

Choose Claude Sonnet 4.6 if: you need best-in-class safety calibration, top tool-calling and agent planning (e.g., enterprise agents, regulated customer workflows, complex codebase automation), or you value the external SWE-bench (75.2%) and AIME (85.8%) results. Choose Grok 4.1 Fast if: you run high-volume production workloads where cost is the primary constraint (Grok is ~30× cheaper), or your workload prioritizes strict structured-output, constrained rewriting, or cost-sensitive customer support pipelines.