How to Write Legal Prompts That Actually Work

The most common complaint attorneys have about Claude is that the output isn't good enough to use. Nine times out of ten, the problem isn't Claude — it's the prompt. Vague instructions produce generic output. Specific, well-structured prompts produce drafts you can edit and file.

This isn't about learning a complicated technical skill. It's about giving Claude the same information you would give a very capable associate who just started working for you.

The Core Framework: Role, Context, Task, Format

Every effective legal prompt has four elements: a role, context, a task, and a format specification. You don't need all four for every prompt, but when output is disappointing, one of these is usually missing.

The strong prompt specifies who Claude is playing (experienced PI attorney), who the audience is (insurance adjuster at a specific carrier), gives concrete facts, and specifies the exact structure and length. The output is ready to edit; the weak prompt output needs to be almost entirely rewritten.

1. Set a Role

Starting your prompt with “You are a [practice area] attorney” meaningfully improves output. It calibrates Claude's vocabulary, tone, and the assumptions it makes about what you need. “You are a criminal defense attorney in Minnesota writing a suppression motion” is more useful than a context-free request.

You can also specify the audience: “You are drafting for a USCIS adjudicator” or “You are writing for a client with no legal background.” Claude adjusts its output accordingly.

2. Give Specific Facts

This is where most attorney prompts fail. “Car accident” is not context. The specific mechanism of injury, the diagnosis, the treatment, the damages figures, the insurance carrier — these details are what Claude uses to produce output that sounds like your case, not a generic template.

You don't need to write beautifully organized facts. A bullet-point data dump works fine:

Claude will organize and synthesize these facts into a coherent narrative. Your job is to make sure all the relevant facts are in there.

3. Specify the Format

Tell Claude exactly what you want: the sections, the length, the tone, and who it's going to. “Two pages, professional tone, with headers for Liability / Damages / Demand” will produce a document that looks like what you need. Without format instructions, Claude makes its own choices — sometimes they match what you wanted, often they don't.

Useful format instructions for legal work:

• →"Organize with headers for [list sections]"
• →"Under two pages / three pages / one page"
• →"Use numbered paragraphs" (for formal legal documents)
• →"Plain language — no legal jargon" (for client letters)
• →"Professional and firm" / "Empathetic and clear" (tone)
• →"Memo format: Question Presented / Brief Answer / Analysis / Conclusion"

4. Iterate — Don't Start Over

The biggest efficiency gain in working with Claude is learning to iterate rather than rewrite your prompt from scratch when the output isn't quite right. A first draft from Claude is a starting point, not a finished product. Follow up in the same conversation:

• →"The liability section is too thin. Expand it with more specific facts about the defect."
• →"Shorten this to one page."
• →"The tone is too aggressive. Make it more professional and less combative."
• →"Add a paragraph about the impact on daily life and activities."
• →"Rewrite the demand paragraph to be firmer and include a specific deadline."

Claude maintains the context of the entire conversation, so it knows what document you're revising. You don't need to re-explain everything — just describe the change you want.

5. Paste the Document In

For document review and revision tasks, paste the actual document into Claude rather than describing it. “Review this contract for one-sided provisions [paste contract]” will always produce better output than “Review a software services agreement for one-sided provisions.” Claude works with what you give it — the more specific and concrete, the better.

The One-Sentence Summary

Treat Claude like a very capable associate who needs to be briefed: tell it who it is, give it the specific facts, describe exactly what you need, and specify the format. Then iterate from the first draft rather than starting over.

Most attorneys who feel like Claude “doesn't work” are giving it the kind of one-line instruction they'd give a search engine. It's a different tool. Brief it like a person, and the output will start looking like work you can actually use.