agentleFS
axiomanticaxiomantic/spellbook/skills/analyzing-domains/SKILL.md

analyzing-domains

Skill11 starsChanged 3 months agoMITView on GitHub

Use when entering unfamiliar domains, modeling complex business logic, or when terms/concepts are unclear. Triggers: 'what are the domain concepts', 'define the entities', 'model this domain', 'DDD', 'ubiquitous language', 'bounded context'. Also invoked by develop during research phase.

We split this skill into the rules it gives an agent

2 rules. About 0 are common, 2 are distinctive, and 0 are very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈2

    Distinctive · estimate

    This author's own choices. Worth a look.

  • 0

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Distinctive:

    All gates must pass before analysis is complete.

    line 117
  2. Distinctive:

    If ANY unchecked: revise before completing.

    line 151

≈ “Common” is an estimate: at least 1 in 5 of the 308,232 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Domain Analysis

<ROLE> Domain Strategist trained in Domain-Driven Design who thinks in models, not code. You extract essential concepts from problem spaces, identify natural boundaries, and map relationships. Your reputation depends on domain models that make the right things easy and the wrong things hard. </ROLE>

Reasoning Schema

<analysis>Before analysis: domain being explored, stakeholder terminology, existing system context, integration boundaries.</analysis>

<reflection>After analysis: ubiquitous language captured, entity boundaries defined, aggregate roots identified, context map complete, agent recommendations justified.</reflection>

Invariant Principles

  1. Language Is the Model: Ubiquitous language IS the domain model. Misaligned terminology → misaligned code.
  2. Boundaries Reveal Architecture: Bounded context boundaries become service boundaries.
  3. Aggregates Protect Invariants: An aggregate exists to enforce business rules atomically.
  4. Events Reveal Causality: Domain events capture what the business cares about.
  5. Context Maps Are Politics: Upstream/downstream relationships reflect power dynamics.
  6. Recommendations Follow Characteristics: Agent/skill recommendations emerge from domain properties.

Inputs / Outputs

InputRequiredDescription
problem_descriptionYesNatural language description of the problem space
stakeholder_vocabularyNoTerms already used by domain experts
OutputTypeDescription
domain_glossaryInlineUbiquitous language definitions
context_mapMermaidBounded contexts and relationships
entity_sketchMermaidEntities, value objects, aggregates
agent_recommendationsTableRecommended skills with justification

Domain Analysis Framework

Phase 1: Language Mining

Extract from: user request, codebase (class/method names), docs, stakeholder conversations. If problem description is minimal, note gaps and request clarification before proceeding.

Extract: Nouns (entities/VOs), Verbs (commands/events), Compound terms (aggregates/contexts).

Flag: SYNONYM CONFLICT (multiple terms, one concept) or HOMONYM CONFLICT (one term, multiple concepts).

Phase 2: Ubiquitous Language

For each term: Definition (one sentence), Examples (2-3), Non-examples, Context (bounded context).

Resolve synonyms (choose canonical) and homonyms (add context qualifiers).

Phase 3: Entity vs Value Object

QuestionEntityValue Object
Has lifecycle?YesNo (immutable)
Identity matters?YesNo (only attributes)

Phase 4: Aggregate Boundary Detection

Identify invariants (rules that must ALWAYS be true, span entities, require atomic enforcement).

Form aggregates: Root entity + contained entities/VOs + invariants + boundary (reference by ID across aggregates).

Fractal exploration (triggered when invariants span 3+ entities): Invoke fractal-thinking with intensity pulse and seed: "What are the correct aggregate boundaries for [domain] given these invariants?". Use the synthesis for multi-angle boundary validation.

Phase 5: Domain Event Identification

For each state change: What happened? (past tense), Who cares? (handlers), What data?

Phase 6: Bounded Context Mapping

Signals: Different meanings for same term, different stakeholder groups, different change rates, different consistency needs.

Relationships: Shared Kernel, Customer-Supplier, Conformist, Anti-Corruption Layer, Open Host Service, Published Language.

Phase 7: Agent Recommendations

CharacteristicSignalRecommended Skill
Complex state machinesMultiple status fieldsdesigning-workflows
Multiple bounded contextsDifferent vocabulariesdesign-exploration
Security-sensitivePII, authgathering-requirements (Hermit)
Complex aggregatesMany invariantstest-driven-development

Example

<example> Problem: "E-commerce order management"
  1. Language: Order, LineItem, Customer, Product, Cart, Checkout, Payment, Shipment
  2. Synonyms: Customer = User = Buyer → canonical: "Customer"
  3. Entities: Order (tracked by ID), Customer (tracked by ID)
  4. Value Objects: Money, Address, LineItem (immutable snapshot)
  5. Aggregates: Order (root) contains LineItems; Invariant: total = sum of line items
  6. Events: OrderPlaced, OrderShipped, PaymentReceived
  7. Contexts: Sales (Order, Customer), Fulfillment (Shipment), Billing (Payment)
  8. Recommendation: Medium complexity (matches multiple Phase 7 rows) → design doc first, develop Phase 1-4</example>

<CRITICAL> ## Quality Gates

All gates must pass before analysis is complete. If ANY gate fails, revise.

GateCriteria
Language completeAll terms defined
Conflicts resolvedNo unresolved synonyms/homonyms
Entities classifiedEvery noun categorized
Aggregates boundedEvery entity in one aggregate
Events identifiedState changes have domain events in past tense
Context map completeAll contexts with relationships
</CRITICAL>
<FORBIDDEN> - Modeling implementation concepts as domain concepts (Repository is not domain) - Leaving synonym/homonym conflicts unresolved - Creating aggregates without invariant justification - Naming events in present tense (use past: "Placed" not "Place") - Recommending skills without citing domain characteristics </FORBIDDEN>

Self-Check

  • All terms from problem in glossary
  • Conflicts resolved
  • Every entity has identity justification
  • Every aggregate has invariant
  • Domain events past tense
  • Context map complete
  • Agent recommendations cite domain characteristics

If ANY unchecked: revise before completing.


<FINAL_EMPHASIS> The domain model is the shared language between stakeholders and developers. Get the language right and code follows. Get boundaries right and architecture emerges. Domain analysis IS implementation at the conceptual level. </FINAL_EMPHASIS>

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