# Systems Engineering Design Analysis — Agent Instruction Architecture A concise systems-engineering analysis; see [Chapter 7](07_se_design_analysis.md) for the developed argument. ## 1. Architecture & Structural Design ### 1.1 Layered Separation of Concerns Authority, responsibility and execution capability are different. The owner sets purpose and reserved decisions; roles describe contributions; assignments and hosts establish permitted effects. Instructions request behaviour, while particular tool and host mechanisms can enforce narrower properties. ### 1.2 Modularity & Encapsulation Active deliverables maintain ScopeOfWork, useful Design content and dependency conditions. They are units of meaning and work, not necessarily isolated code modules. Shared code and cross-deliverable undertakings require explicit integration responsibility rather than compulsory folder-bound staffing. ### 1.3 Interface Contracts Assignments, dependency conditions, tool schemas and product operations are interfaces with different semantics. Syntactic validity does not establish that an input is suitable. A strict tool schema is useful without making every agent assignment a sealed parameter table. ## 2. Configuration Management & Baseline Control ### 2.1 Version Control as a Development Record Git preserves committed versions and supports comparison and recovery. PRs explain changes and their examination. Neither is a complete event record of external services, unsaved work or human engagement. ### 2.2 Identifying the Subject of Acceptance A revision or digest identifies content. It does not establish truth or a human act. Applicable product contracts can require specific bindings; ordinary development follows its current authority rather than inheriting a universal reapproval duty from every new commit. ### 2.3 Change Impact Derived dependency views identify potentially affected consumers. They do not mark every consumer stale or establish that a missing edge means independence. Meaningful changes are investigated; reserved decisions remain with the owner. ### 2.4 Preservation Current meaning is edited in place. Committed history and selected tags preserve earlier versions. Extra records are warranted by a concrete consumer, acceptance requirement or recovery need; immutable run snapshots are not a general duty. ## 3. Verification & Validation ### 3.1 Decomposition and Integration The V-model supplies useful questions about the relation between requirements and examination of the result. It does not uniquely prescribe stages, documents or separate agents. Implementation and use can expose requirements that need revision through the appropriate authority. ### 3.2 Consequential Checkpoints Routine reversible work can be inspected, ordinary implementation receives a focused check, and consequential numerical, persistence, permission or destructive changes warrant targeted regression checks and independent scrutiny. Passing a selected check does not constitute professional acceptance. ### 3.3 Coverage Analysis Coverage measures need a subject. Migration-row accounting, code exercised and numerical cases establish different bounded facts. None establishes the complete adequacy of the product or its requirements. ### 3.4 Traceability Traceability is useful when it connects a real question to sources, assumptions, consumers and checks. Repeating those relationships in multiple registers can create inconsistent answers without adding useful evidence. ## 4. Safety & Reliability Engineering ### 4.1 Fault Containment Host permissions and domain-controlled operations can restrict actual effects. A role label or natural-language instruction alone is not a sandbox. Containment claims must identify the path enforced and possible paths outside it. ### 4.2 Failure Visibility Unknown outcomes, refusals and unexecuted work must remain distinguishable from success where recovery or reliance depends on that distinction. Visibility is an implementation property to examine, not a consequence of naming an invariant. ### 4.3 Context Boundaries A clear assignment and identified sources help establish the basis of a result. They cannot erase model priors or guarantee that a sealed brief captures every relevant condition. Privacy and access limits belong in actual host and product boundaries. ## 5. Requirements Engineering ### 5.1 Decomposition & Allocation Decomposition interprets intention into workable results and relationships. Its completeness cannot be proven merely from a flat folder layout or a populated allocation table. ### 5.2 Requirements Traceability Views Generate the view needed by the actual consumer. Current ScopeOfWork, Design and consumer-owned needs provide the primary development sources; missing mappings remain explicit rather than being counted as absence of impact. ### 5.3 Acceptance Criteria Allocation The PRD and acceptance criteria constrain development, but do not compile into a unique implementation. Re-derivation incorporates prior defects, use and owner interpretation. Its value depends on retaining learning as well as producing code. ## 6. Control and Feedback ### 6.1 The Working Loop Purpose, action, examination, correction and integration can remain with one agent or involve contributors. Ownership continues through ordinary repairs. This is a useful feedback description, not a proof of convergence. ### 6.2 Feedback Across Contributions Independent work can proceed while another branch is unresolved. Shared writes, resource limits and integration costs may justify sequencing. Recovery from an interruption must be assessed through an actual continuation attempt. ### 6.3 Authority and Stopping Standing authority permits ordinary progress; a reserved decision stops the affected action. Human judgment shapes the undertaking throughout. Completion of the agreed result stops work without a compulsory closeout packet. ## 7. Specification and Formal Methods ### 7.1 Invariant Systems A stated value, procedure and tool property require different grounds. A named rule needs defined scope, an enforcement mechanism and evidence of its operation. Current adopted contracts are consulted in their current homes; [Appendix A](appendix_a_invariant_catalog.md) retains the catalog comparison. ### 7.2 Preconditions and Postconditions Executable checks can enforce explicit input conditions and produce bounded results. Prose assignments do not guarantee stochastic agent postconditions. Formal proof would require a model, assumptions and a proof of the stated property. ### 7.3 The Type System Types can make interface distinctions checkable while leaving semantic adequacy open. The following **legacy review-format vocabulary** is retained exactly because [Compatibility formats §10.6](../COMPATIBILITY_FORMATS.md#106-review-finding-severity) cites this section: ```text FindingSeverity : CRITICAL | MAJOR | MINOR | OBSERVATION ``` These values classify review findings about deliverable content for consumers of that format. They are distinct from historical governance-verifier severities (`BLOCK`, `REVIEW`, `WARN`, `INFO`, `NOT_APPLICABLE`) and the former agent-conformance rubric. Their preservation does not require every current review to use the legacy format or reinstate its lifecycle gates. No enum value itself establishes the technical severity of a finding. Likewise, `FACT`, `ASSUMPTION`, `PROPOSAL` and `TBD` can support a review without exhaustively or exclusively classifying all claims. Correct spelling of a label is not evidence that its interpretation is correct. ### 7.4 State Machines Product request, persistence and operation protocols can benefit from explicit state machines faithful to their actual transitions and outcomes. Work, evidence and acceptance have several independently variable relations. ## 8. Human Factors & Decision Authority ### 8.1 Responsibility Allocation Agent 0 holds purpose and continuity with the person. Other roles are used as the undertaking needs them; TASK does not delegate. Agents can perform substantial reckoning within authority. The person's situated, committed judgment is not transferred by increased agent capability. ### 8.2 Cognitive Load Clear current artifacts and concise returns can reduce investigation. Labels, registers and records can also obscure relevant questions. Their cost includes the human and agent attention needed to maintain and interpret them. ### 8.3 Proportionate Rigor Rigor concerns adequate examination of consequential failures. Control count is not a useful substitute. A control earns its place through the failures it addresses, its cost and the limits of alternative feedback. ## 9. Cross-Cutting Patterns ### 9.1 Tree, Graph, Network and Attention Composition, dependency and relevance are views of the undertaking. Attention relates them for a purpose. They need not be four separately maintained datasets. ### 9.2 Local Meaning with Derived Views Consumer declarations support on-demand queries without a competing authored graph. A fresh query is still only as adequate as the declarations it reads. ### 9.3 Evidence and Its Limits Provenance enables examination but does not validate an inference. Independent review is valuable where assumptions and consequences warrant it; several checks can still share an error. ### 9.4 Complementary Controls A control contributes assurance only within its actual coverage. Several layers do not prove that no single failure can compromise a result. ## 10. Assessment The arrangement preserves purpose, evidence, integration responsibility and reserved human decisions through inspectable sources and selected checks. Sustained productivity, recovery and transfer to other practitioners remain empirical questions. [Appendix E](appendix_e_development_history.md) preserves the development evidence and its limits. ### 10.1 The Revisable Relationship Ontology, epistemology, praxeology and axiology supply enduring questions. Architecture supplies revisable responses. An SE analysis should show how a response addresses those questions, what it costs and what evidence supports it. It should not treat an intelligible design as proof of accountable practice.