Legal documents are formulaic enough that generated drafts read convincingly on the first pass. The failures appear in the parts that determine whether the document works.
Citation is a verification problem, not a formatting one
Legal writing depends on citing authority that exists, says what it is claimed to say, and remains good law. Each of those is a separate check.
A model produces citations shaped correctly because the format is highly regular. Correct shape carries no information about whether the case exists or supports the proposition.
US courts have sanctioned filings containing fabricated authority, and the response has been standing orders in many districts requiring certification that citations were verified.
Jurisdiction changes the answer, not just the wording
The same question about a contract term, an employment classification or a landlord obligation resolves differently across states, and sometimes across federal circuits.
Generated text tends to produce the modal American answer, which is the one that appears most often in training material rather than the one that governs the client.
Because the wrong answer is stated in the same confident register as the right one, the error is invisible to anyone who does not already know the jurisdiction's rule.
Adversarial reading raises the cost of ambiguity
Ordinary business writing is read cooperatively. Legal writing is read by someone looking for the interpretation that favors their client.
A sentence that admits two readings becomes the opposing argument, so drafting is largely the work of closing off readings nobody intended.
That work requires anticipating a specific adversary's incentives, which is a different task from producing a sentence that reads well.
The strongest uses sit around the document
Firms report real gains from summarizing discovery volume, comparing versions of a contract, and drafting routine correspondence where the content is already settled.
Those tasks share a property: a human with the file can check the output quickly, and an error is visible rather than latent.
The tasks that resist automation are the ones where checking the output is as much work as producing it, which describes most substantive drafting.
Supervision duties do not transfer
American professional responsibility rules place the obligation on the licensed attorney regardless of what produced a filing. Delegation to software changes nothing about who answers to the court.
That allocation means the efficiency gain is capped by the review time the rule requires, because the review cannot be skipped.
Firms that priced the savings on drafting time alone found the arithmetic changed once mandatory verification was counted as part of the work.