The context window is the maximum amount of text — measured in tokens — that a large language model can process at one time, determining how much document content, conversation history, and instructions the model can consider when generating a response.
Last reviewed: 2026/05/19
Document Drafting AI is software that uses large language models to generate, edit, or refine legal documents — including contracts, briefs, letters, and pleadings — based on lawyer-provided instructions or templates.
Tech / ModelA large language model (LLM) is an AI system trained on large volumes of text data to predict and generate human-like text; it serves as the core engine underlying most legal AI tools for research, drafting, and document analysis.
Tech / ModelIn the context of large language models, a token is the basic unit of text the model processes — roughly a word fragment, word, or punctuation mark — used to measure both input length and output length, with practical limits imposed by the model's context window.
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Last reviewed: 2026/05/19. Definitions are written by the LawyerAI Editorial team. Commercial relationships are disclosed and do not determine editorial scores or conclusions. See our Sponsorship & Affiliate Disclosure.
The context window is the maximum amount of text — measured in tokens — that a large language model can process at one time, determining how much document content, conversation history, and instructions the model can consider when generating a response.
The context window defines the practical scope of what a legal AI tool can analyze in a single interaction. For lawyers working with long documents — comprehensive M&A agreements, multi-party litigation files, or extensive deposition transcripts — the context window limit directly determines whether the AI can consider the entire document or only a portion.
A short context window on a complex contract creates a specific risk: the model may be analyzing only a section of the contract at a time, missing defined terms established elsewhere, cross-references between sections, or the overall risk allocation structure that emerges only from the document as a whole. A lawyer reviewing a contract for consistency issues may get misleading AI output if the tool is processing the document in disconnected segments.
Context windows have grown substantially as the technology has matured. Models in 2023 typically had 4,000–8,000 token limits, making full-document analysis of anything but the shortest contracts impractical. Current enterprise models commonly offer 128,000 to 1,000,000+ tokens — sufficient for multi-hundred-page documents.
Lawyers should verify a tool's effective context window for the specific task, not just the model's nominal maximum. System prompts, tool instructions, and other overhead consume context before the document text is loaded.
Legal AI vendors select or build on models with context windows appropriate for their use cases. Harvey AI and similar enterprise legal tools use high-context models to support full-document analysis of lengthy legal agreements. Contract review tools like Luminance and Kira Systems process documents through specialized extraction pipelines that may handle context management differently than pure LLM interaction.
Some tools display or document their effective processing limits for specific document types. Others require users to discover limits through experience — noticing when a tool's responses about document content become inconsistent with the actual text.
For e-discovery platforms processing large document collections, the relevant capacity metric is not the single-document context window but the batch processing architecture — how many documents can be classified per hour and at what level of analysis depth. These platforms manage context at a per-document level rather than across the entire collection simultaneously.
When context window limits are a concern for a specific matter, lawyers should test the tool's behavior on representative document samples before committing to an AI-assisted workflow.