Claude Sonnet 4.6 vs Grok 4 for Research

What Research demands: synthesis of long documents, accurate extraction, nuanced tradeoff reasoning, reproducible multi-step plans, and safe handling of sensitive or risky prompts. The task relies primarily on strategic_analysis, faithfulness, and long_context — the three tests in our Research suite. In our testing both Claude Sonnet 4.6 and Grok 4 score 5/5 on those primary Research tests, so the headline capability is equal. Deciding a winner therefore hinges on supporting skills: tool_calling (to orchestrate retrieval and citation workflows), safety_calibration (to avoid unsafe or misleading claims), agentic_planning (to decompose literature tasks and recover from failures), structured_output (for consistent citation schemas), and context_window (to reduce chunking). Claude Sonnet 4.6 leads on tool_calling (5 vs 4), safety_calibration (5 vs 2), and agentic_planning (5 vs 3) in our tests, plus a much larger context_window (1,000,000 tokens vs Grok 4's 256,000). Grok 4 adds file ingestion (text+image+file->text modality) and stronger constrained_rewriting (4 vs 3), which matter for ingesting PDFs and producing ultra-compressed summaries. Because no external benchmark is present in the payload, our internal scores are the primary evidence for the Research verdict.

1. Large-scale literature synthesis (100k+ tokens): Both scored 5/5 on long_context in our testing, but Claude Sonnet 4.6's 1,000,000-token context_window reduces the need to chunk manuscripts and maintains coherence across an entire literature corpus. 2) Reproducible agentic workflows (automated retrieval, multi-step extraction): Sonnet 4.6 scored higher on tool_calling (5 vs 4) and agentic_planning (5 vs 3) in our tests, so it better sequences retrieval and failure recovery for multi-source synthesis. 3) Safety-sensitive review (medical/ethics checks): Sonnet 4.6's safety_calibration is 5 vs Grok 4's 2 in our testing, so Sonnet more reliably refuses or reframes unsafe prompts while permitting legitimate analysis. 4) Tight executive summaries and character-limited abstracts: Grok 4 outperforms on constrained_rewriting (4 vs 3), making it the better pick when compressing findings into hard limits. 5) Ingesting raw files (PDFs, supplemental data): Grok 4 supports text+image+file->text modality (explicit in the payload), so it simplifies direct file ingestion workflows compared with Sonnet 4.6's text+image->text modality.

For Research, choose Claude Sonnet 4.6 if you need end-to-end, safety-conscious literature synthesis with advanced tool orchestration and the largest context window (tool_calling 5 vs 4; safety_calibration 5 vs 2; agentic_planning 5 vs 3; 1,000,000 vs 256,000 tokens). Choose Grok 4 if your priority is direct file/PDF ingestion and highly compressed summaries or abstracts (file modality + constrained_rewriting 4 vs 3), and you can accept lower safety calibration and weaker agentic planning in exchange.