The Senior Developer, Staff and Principal Engineer

All courses / AI Developer / Module 3 / Chapter 14

Learning objectives

After the lesson the participant can:

• Explain what AI makes cheaper and does not make cheaper in each of the senior's four jobs
• Design controls for the review bottleneck: inflow limits, reviewable changes, tiers, first-view samples and seeded errors
• Draft a professional-judgement clause with its six parts and its limits
• Explain the three duties specific to staff and principal engineers

Key concepts

The senior's four jobs

Reviewer, mentor, technical decision-maker and keeper of context. An assistant with retrieval finds text; it does not find reasons that were never written and cannot tell a deliberate oddity from an accident.

Review budget

A named share of the senior's working time for review, with a mentoring share beside it, changed only by recorded decision. It is the lever that keeps review from quietly becoming shallower as inflow rises.

Professional-judgement clause

Six parts in the role charter: the right to hold a change, the right to the explanation without the tool, the right to decline ownership, the right to record dissent, no use target in appraisal, and the right to unassisted work. It is not a veto and not immunity.

A second model is not a second opinion

One of four mechanisms that worsen the bottleneck, beside anchoring on the proposal, vigilance on a mostly correct stream and confidence in the author. Model errors are correlated, so an AI comment is never the human review.

Keeping the hands in

A senior or principal who only reviews may lose the working theory of the system, because the theory is maintained by changing the system. The charter for staff roles therefore includes a build share as well as a review share.

Interactive exercises

Do them here and get feedback at once. Choose a card and then where it belongs, or drag it.

Teaching plan

Discussion

1. Why does the chapter place the right to hold in a role charter rather than in a general policy on AI tools?
2. The senior is not the default owner of every change they have reviewed. What happens in your team to a change whose reviewer cannot pass the Understand test?
3. Linnea Sjöberg holds 17 years of history of the case system; Ralf Hauser is one of five maintainers near retirement. What does succession look like before the farewell rather than at it?

Written exercise

Self-test

Choose an answer to see whether it is right, or open the answer below each question.

1. Which of the following is one of the six parts of the professional-judgement clause?

   1. The right to veto any generated change permanently, without review by peers
   2. The right to decline ownership of a change that fails the stewardship tests
   3. The right to see each colleague's acceptance rate
   4. The right to approve a change on the strength of an AI review comment
   Show the answer

   B. The right to decline ownership of a change that fails the stewardship tests
   The clause gives the rights to hold, to the explanation, to decline ownership, to record dissent and to unassisted work, and bars use targets in appraisal. It is explicitly not a veto and not immunity.

2. What happens, under the clause, to a hold that is not answered in time?

   1. It lapses to the next decision-maker named in the charter
   2. It becomes permanent until the senior withdraws it
   3. It is overridden automatically by the pipeline after two days
   4. It is escalated to the works council for a ruling
   Show the answer

   A. It lapses to the next decision-maker named in the charter
   The clause is time-limited and reviewed by peers. A hold that is not answered in time lapses to the next decision-maker in the charter, which is why the chapter says it is not a veto.

3. Why does the charter for staff and principal roles include a build share?

   1. Because staff engineers are cheaper than agents for mechanical changes
   2. Because the works agreement forbids roles that consist only of review and mentoring
   3. Because a reviewer who no longer changes the system risks losing its theory
   4. Because acceptance-rate targets require every engineer to generate code
   Show the answer

   C. Because a reviewer who no longer changes the system risks losing its theory
   The chapter warns that a principal who has not changed the system in two years risks becoming a reviewer who has lost the theory Naur described, so the charter includes a build share beside the review share.