Layer 3: Detail
Scope: one part at a time. Each entry below describes one part from Layer 2: what it does, what it offers and needs at its seams, and what it is made with.
[Part A] (part)
1. Responsibility
[One or two sentences: what this part answers for, starting from its one-line responsibility in Layer 2.]
2. Concepts and states (optional)
- [A thing the part works with], with [its fields].
- [Thing]’s state: [state one], [state two] or [state three].
3. Seams (optional)
- [Part A] to [Part B], offers: [what this part offers, in what form].
- [Part C] to [Part A], needs: [what this part needs, in what condition].
4. Rules
- V1. Given […], when […], then [Part A] [does what].
- Given [an edge or failure the owner gave], when […], then [Part A] [does what].
5. Inside (optional)
- [A piece] (piece), which [does what].
- [Another piece] (piece), which [does what].
6. Limits
- [A number, a testable condition or an observable result] (Layer 1, [quality or topic]).
- [A second limit] (Layer 1, Not supplied: [the quality]).
7. Construction (optional)
- [The means chosen: tool, material or method, and the value it is set to]. Reason: [the Limit it meets].
- Not supplied: [a value nobody has chosen].
8. Costs (optional)
- C3.1. Given [the condition or volume], when [the subject is built, run or changed], then it costs [the amount, or Not supplied: the figure]. Paid by [who].
9. Risks (optional)
- R3.1. Given [a situation], when [it goes wrong], then [the harm]. Severity: [High, Medium, Low or Not rated]. Answered by [the id of a decision, assumption or rule, or Not supplied: the answer].
10. Open Concerns (optional)
- O3.1. Given [the unsettled situation], when [what would settle it happens], then [what follows, and what it feeds]. Raised by [who].
11. Assumptions
- A3.1. [What the part’s rules rest on]. Basis: [why we think so]. If wrong: [what changes].
12. Decisions
- D3.1. [What was chosen about the part’s shape]. Reason: [why].
[Part B] (part)
1. Responsibility
[…]
2. Rules
- V2. Given […], when […], then [Part B] [does what].
3. Limits
- […] (Layer 1, [quality or topic]).
4. Assumptions
None.
5. Decisions
None.