GPT-5.2 vs Claude 4.5 for Legal Contract Analysis
We pit OpenAI and Anthropic's best models against complex legal documents. Clause extraction, risk identification, and compliance checking compared.
Legal AI Requirements
Legal contract analysis demands specific AI capabilities: precise extraction of defined terms and obligations, identification of unusual or risky clauses, cross-reference checking between sections, comparison against standard templates, and generation of plain-language summaries. Errors can have significant financial and legal consequences.
We tested both models on a standardized suite of 200 contracts across M&A agreements, employment contracts, licensing deals, and real estate leases. Each contract was reviewed by practicing attorneys to establish ground truth.
Clause Extraction & Identification
GPT-5.2 achieves 94.7% accuracy on clause extraction — identifying and categorizing all material clauses in a contract. Claude 4.5 scores 96.2%, with particular strength in identifying implied obligations and cross-reference dependencies.
For risk identification (unusual terms, one-sided provisions, missing standard protections), Claude leads more decisively: 91.4% recall vs GPT-5.2's 87.8%. Claude's training emphasis on careful analysis appears to benefit legal reasoning, where thoroughness matters more than speed.
Compliance & Regulatory Checking
When checking contracts against regulatory requirements (GDPR, SOX, industry-specific regulations), GPT-5.2 shows slightly better performance — 93.1% vs Claude's 91.8%. GPT-5.2's broader knowledge base gives it an edge on obscure regulatory requirements, particularly in specialized industries.
Both models struggle with jurisdiction-specific nuances — state-level variations in US law, differences between EU member state implementations, and recent regulatory changes not yet in training data. Human review remains essential for jurisdiction-specific compliance.
Practical Workflow Comparison
In a realistic workflow (upload contract, extract key terms, identify risks, generate summary), Claude 4.5 produces more organized and actionable output. Its summaries clearly separate findings by severity, include specific clause references, and suggest remediation language.
GPT-5.2 produces more comprehensive analysis but requires more prompting to achieve optimal formatting. Its strength is handling follow-up questions — attorneys can ask clarifying questions and GPT-5.2 maintains excellent context about the specific contract under review.
Recommendation
For dedicated legal contract analysis platforms, Claude 4.5 is the better choice — its precision, thoroughness, and structured output align well with legal workflow requirements. For general-purpose legal assistants where attorneys ask varied questions, GPT-5.2's broader knowledge and conversational ability give it an edge.
Cost-wise, both models are comparable for legal use cases (contracts are typically within standard context limits). Many law firms are adopting a hybrid approach — Claude for systematic contract review, GPT-5.2 for research and drafting. Try both through Vincony's unified API to evaluate with your specific document types.