---
title: "Letter when a flat fee should change because a tool did the work (United States)"
url: "https://ailawframework.com/precedents/costs-billing-and-litigation-funding/us-flat-fee-change-after-gai-use"
type: "precedent"
site: "AI Law Framework"
id: "a42-us-flat-fee-change-after-gai-use"
area_id: "A42"
kind: "letter"
ai_level: "yellow"
version: 1
task_ids: ["A42-T1-R1", "A42-A20260923-2"]
law_stated_as_at: "2026-10-22"
---

# Letter when a flat fee should change because a tool did the work (United States)

> A letter telling the client that a flat fee may no longer be reasonable because a generative AI tool has reduced the work, and asking agreement to a revised amount before further work is billed that way.

Canonical page: https://ailawframework.com/precedents/costs-billing-and-litigation-funding/us-flat-fee-change-after-gai-use  
Law stated as at: 2026-10-22

Site index for agents: https://ailawframework.com/llms.txt

## Key facts

- Kind: Letter. A letter or email you adapt and send.
- Practice area: [Costs, billing & litigation funding](https://ailawframework.com/precedents/costs-billing-and-litigation-funding.md)
- Jurisdictions: United States
- AI level: Yellow. You and the tool draft together, with you directing. You check every statement you rely on.
- Law stated as at: 2026-10-22
- Status: Maintained. Checked on 2026-10-22 against the 3 authorities it cites, for United States.

## When to use it

Use when the engagement is a flat fee and a tool has meant the lawyer will do little or no work for that fee. Do not use it to raise a fee after the work is done, or to bill hourly time that was not spent.

## Used for these tasks

- [Draft a costs disclosure from the matter scope and the scale or estimate](https://ailawframework.com/obligations/costs-billing-and-litigation-funding/draft-a-costs-disclosure-from-the-matter-scope-and-the-scale-or-estimate.md)
- [Compare a draft bill to the last costs disclosure and any updates](https://ailawframework.com/obligations/costs-billing-and-litigation-funding/compare-a-draft-bill-to-the-last-costs-disclosure-and-any-updates.md)

## How AI may be used

A tool may draft the description of the remaining scope from the lawyer's note. The lawyer decides the revised amount and whether the original fee is still reasonable.

**AI may:**

- Restate the original scope and the remaining tasks from the engagement letter and the lawyer's note
- Flag a draft that changes the fee without showing the original amount

**AI must not:**

- Must not set the revised fee
- Must not say the original fee was unreasonable as a conclusion
- Must not send the letter

**The lawyer checks:**

- The original fee, the scope, and the proposed amount are all stated
- The change is communicated before the firm relies on the new basis, as Rule 1.5(b) requires for a change in the basis or rate
- The letter is not used to charge for time no person spent

## Authorities

- [ABA Standing Committee on Ethics and Professional Responsibility, Formal Opinion 512, Generative Artificial Intelligence Tools (July 29, 2024)](https://www.americanbar.org/content/dam/aba/administrative/professional_responsibility/ethics-opinions/aba-formal-opinion-512.pdf)
- [ABA Model Rules of Professional Conduct, Rule 1.5 (Fees)](https://www.americanbar.org/groups/professional_responsibility/publications/model_rules_of_professional_conduct/rule_1_5_fees/)
- [ABA Model Rules of Professional Conduct, Rule 1.4 (Communications)](https://www.americanbar.org/groups/professional_responsibility/publications/model_rules_of_professional_conduct/rule_1_4_communications/)

## Full text and drafting notes

The full text and the drafting notes are not part of this public page. Signed-in firm accounts can read them at https://ailawframework.com/precedents/costs-billing-and-litigation-funding/us-flat-fee-change-after-gai-use and through the signed-in MCP connector https://ailawframework.com/mcp/firm.

*Practice guidance for planning and review. Confirm current primary sources and the requirements of the actual matter. This is general information, not legal advice.*