The Developer Loop Defined: Five Functions, Delegation Ladder and Stewardship

All courses / AI Developer / Module 1 / Chapter 4

Learning objectives

After the lesson the participant can:

• Explain the five developer functions and assign a piece of work to one of the ten classes of development work
• Set a ceiling for a work class by answering the five questions and taking the lowest level
• Apply the tests Name, Understand and Revert to a recent change and to the owner of a repository
• Draft a delegation profile for one team with an independent oracle and a stop path

Key concepts

The developer loop

Five functions that run as a loop: D1 Frame, fixing the problem and the intent; D2 Design, choosing the constraints; D3 Build, producing and directing the making of software; D4 Prove, showing that it is right; and D5 Steward, owning the software over time.

The lowest of five answers governs

The ceiling for a work class is the lowest level allowed by reversibility, blast radius, who is affected, evidence, and the strength of the independent checks. The fourth and fifth answers can only lower a ceiling that the first three have allowed.

The Level 4 prohibitions

Level 4 Autonomous is never used for a production change without a gate the change cannot alter, for security-critical or safety-critical code without review by a named developer, for the agent's own mandate, oracles or gates, for irreversible actions on production data, or for decisions about a named person.

The stewardship principle

AI may draft, generate, refactor and, within a mandate, execute; it may not own. A named developer or team passes three tests for every change in production: Name (identifiable in the ownership record), Understand (can explain it without the tool) and Revert (authority, access and time outside the pipeline).

The independent test oracle

The oracle is the means of deciding whether observed behaviour is correct. The corollary of the principle is that it must be independent of the generator: tests written by the same assistant in the same session restate the code's assumptions.

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. The fourth and fifth answers, evidence and independent checks, can only lower a ceiling. Why does the chapter not let strong evidence raise a ceiling that reversibility or blast radius has capped?
2. Switch the assistant off and ask the owner what the change does. Which recent change in your team would pass the Understand test, and which would not?
3. Hansa Mutual allows one Level 3 Bounded class, patch-level dependency updates. What has to stay true for that class to remain acceptable under the ladder?

Written exercise

Self-test

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

1. What ceiling does the chapter recommend for the work class review?

   1. Level 0 Advisory, because no AI comment may appear on a pull request
   2. Level 2 Supervised, because an AI approval counts once a developer confirms it
   3. Level 3 Bounded, for changes whose checks have all passed in the pipeline
   4. Level 1 Assisted: AI comments are input to a human reviewer, never an approval
   Show the answer

   D. Level 1 Assisted: AI comments are input to a human reviewer, never an approval
   The table of ceilings sets review at Level 1 Assisted: AI comments are input to a human reviewer, and an AI comment never counts as a human approval.

2. Which of these checks does the chapter classify as not independent of the generator?

   1. Characterisation tests recorded from the running legacy system
   2. Tests written by the same assistant in the same session as the code
   3. Static analysis and type checking with fixed rules
   4. Tests derived from the specification record by a different person before the code
   Show the answer

   B. Tests written by the same assistant in the same session as the code
   Tests from the same assistant in the same session restate the code's assumptions, so a wrong reading of the requirement is in both. The other three are independent in method, authorship or time.

3. Under the Name test, which ownership entry fails?

   1. A named team with a reachable lead recorded in the ownership record
   2. A named developer with a deputy recorded for periods of absence
   3. A department such as Policy Systems recorded as owner of the estate
   4. A tech lead recorded as owner of the repositories of one product team
   Show the answer

   C. A department such as Policy Systems recorded as owner of the estate
   The chapter says a repository whose owner has left, or whose owner is a department such as Policy Systems, does not pass: the owner must be identifiable by name or as a named team with a reachable lead.