| name | business-evaluation |
| description | [Content] Use when you need to evaluate business idea viability: Business Model Canvas, financial projections, risk matrix, go-to-market, execution plan. |
Codex compatibility note:
- Invoke repository skills with
$skill-name in Codex; this mirrored copy rewrites legacy Claude /skill-name references.
- Task tracker mandate: BEFORE executing any workflow or skill step, create/update task tracking for all steps and keep it synchronized as progress changes.
- User-question prompts mean to ask the user directly in Codex.
- Ignore Claude-specific mode-switch instructions when they appear.
- Strict execution contract: when a user explicitly invokes a skill, execute that skill protocol as written.
- Subagent authorization: when a skill is user-invoked or AI-detected and its protocol requires subagents, that skill activation authorizes use of the required
spawn_agent subagent(s) for that task.
- Do not skip, reorder, or merge protocol steps unless the user explicitly approves the deviation first.
- For workflow skills, execute each listed child-skill step explicitly and report step-by-step evidence.
- If a required step/tool cannot run in this environment, stop and ask the user before adapting.
Codex Project-Reference Loading (No Hooks)
Codex uses static project-reference loading instead of runtime-injected project docs.
When coding, planning, debugging, testing, or reviewing, open project docs explicitly using this routing.
Always read:
docs/project-config.json (project-specific paths, commands, modules, and workflow/test settings)docs/project-reference/docs-index-reference.md (routes to the full docs/project-reference/* catalog)docs/project-reference/lessons.md (always-on guardrails and anti-patterns)
Missing/stale context route: If docs/project-config.json, the docs index, lessons.md, CLAUDE.md, AGENTS.md, or any task-required reference doc is missing or stale, auto-run $project-init or the narrow setup route ($project-config, $docs-init, $scan-all, $scan --target=<key>, $claude-md-init) before ordinary project-specific work. If Codex mirrors or AGENTS.md are missing/stale, ask the user to run $sync-codex; do not auto-run it.
Situation-based docs:
- Backend/CQRS/API/domain/entity changes:
backend-patterns-reference.md, domain-entities-reference.md, project-structure-reference.md
- Frontend/UI/styling/design-system:
frontend-patterns-reference.md, scss-styling-guide.md, design-system/README.md
- Spec authoring,
docs/specs/ pathing, or TC format: feature-spec-reference.md, spec-system-reference.md, spec-principles.md
- Behavior/public-contract changes or spec-test-code sync:
workflow-spec-test-code-cycle-reference.md plus the spec docs above
- Derived spec indexes/ERDs/reimplementation guides:
spec-system-reference.md and source Feature Specs under docs/specs/
- Integration test implementation/review:
integration-test-reference.md
- E2E test implementation/review:
e2e-test-reference.md
- Code review/audit work:
code-review-rules.md plus domain docs above based on changed files
Do not read all docs blindly. Start from docs-index-reference.md, then open only relevant files for the task.
[BLOCKING] Execute skill steps in declared order. NEVER skip, reorder, or merge steps without explicit user approval.
[BLOCKING] Before each step or sub-skill call, update task tracking: set in_progress when step starts, set completed when step ends.
[BLOCKING] Every completed/skipped step MUST include brief evidence or explicit skip reason.
[BLOCKING] If Task tools are unavailable, create and maintain an equivalent step-by-step plan tracker with the same status transitions.
Quick Summary
Goal: Evaluate business idea viability to deliver an evidence-backed viability verdict — score + confidence + Pursue/Pivot/Pause/Pass recommendation — grounded in a complete 9-block BMC, 3-year financials with stated assumptions, 5+ risks with mitigation, and a phased execution + GTM plan, so the go/no-go decision rests on traced evidence, never optimism.
Summary:
- Runs after market-analysis: pull its market data in as evidence rather than re-deriving market sizing here — this skill judges viability, it does not research the market.
- Every artifact is evidence-gated — all 9 BMC blocks cite proof, every financial number carries an assumption + source, and each of the 5+ risks needs mitigation AND a residual-risk entry; an unbacked number or block fails the gate.
- The verdict is the load-bearing output: a 1-10 viability score, an explicit confidence tier (95/80/60/<60%) with its evidence basis, a Pursue/Pivot/Pause/Pass call, and the single key condition that must hold to succeed — bias toward skepticism, never optimism.
- Write the result to
docs/knowledge/strategy/business/{slug}.md via the enforced .claude/templates/business-evaluation-template.md, then use a direct user question to route next (domain-analysis recommended) — never auto-decide.
Workflow:
- Capture idea — Problem, solution, target customer
- Load market analysis — Market data from market-analysis
- Business Model Canvas — All 9 blocks with evidence
- Financial projections — 3-year revenue, costs, break-even
- Risk assessment — 5+ risks with mitigation
- Execution plan — 3 phases with milestones
- Verdict — Viability score, confidence, recommendation
Key Rules:
- All 9 BMC blocks required, each with evidence
- Financial projections: explicit assumptions table
- Minimum 5 risks with mitigation AND residual risk
- Verdict must be evidence-backed with confidence declaration
Be skeptical. Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence percentages (Idea should be more than 80%).
Business Evaluation
Step 1: Capture the Idea
From user input, extract:
- One-liner — Elevator pitch in 1 sentence
- Problem — What pain point does it solve?
- Solution — How does it solve it?
- Target customer — Who specifically benefits?
Step 2: Business Model Canvas
All 9 blocks required:
| Block | Key Question | Evidence Required |
|---|
| Customer Segments | Who are we serving? | Market research |
| Value Propositions | What value do we deliver? | Customer pain points |
| Channels | How do we reach customers? | Channel analysis |
| Customer Relationships | How do we maintain relationships? | Retention strategy |
| Revenue Streams | How do we make money? | Pricing research |
| Key Resources | What do we need? | Resource assessment |
| Key Activities | What must we do? | Operational analysis |
| Key Partnerships | Who helps us? | Partner landscape |
| Cost Structure | What does it cost? | Cost analysis |
Step 3: Financial Projections (3 Years)
Revenue Model
| Year | Users/Customers | ARPU | Revenue | Growth |
|---|
Cost Structure
Break-Even
- Monthly burn: ${X}
- Break-even point: Month/Year
- Funding needed: ${X}
Assumptions Table
Every number must list its assumption and source.
Step 4: Risk Assessment
Minimum 5 risks:
| Risk | Likelihood | Impact | Mitigation | Residual Risk |
|---|
Categories to consider: market, execution, financial, competitive, regulatory, technical.
Step 5: Execution Plan
| Phase | Timeline | Focus | Key Milestones |
|---|
| Validation | 0-3 months | Customer discovery, MVP | N interviews, prototype |
| Build | 3-6 months | Core product, early users | Beta launch, first revenue |
| Growth | 6-12 months | Scale, optimize | Revenue target, team size |
Step 6: Go-to-Market
- Launch strategy — How to enter the market
- Initial channels — Top 3 acquisition channels
- Pricing strategy — Model + rationale + competitive comparison
Step 7: Verdict
- Viability score: 1-10 with rationale
- Confidence: 95%/80%/60%/<60% with evidence basis
- Recommendation: Pursue | Pivot | Pause | Pass
- Key condition: What must be true for this to succeed?
Output
Write to docs/knowledge/strategy/business/{descriptive-slug}.md using enforced template from .claude/templates/business-evaluation-template.md.
Next Steps
MANDATORY IMPORTANT MUST ATTENTION — NO EXCEPTIONS after completing this skill, you MUST ATTENTION use a direct user question to present these options. Do NOT skip because the task seems "simple" or "obvious" — the user decides:
- "$domain-analysis (Recommended)" — Analyze domain model from business evaluation
- "$plan" — If ready to plan implementation
- "Skip, continue manually" — user decides
[IMPORTANT] Use task tracking to break ALL work into small tasks BEFORE starting.
External Memory: For complex or lengthy work (research, analysis, scan, review), write intermediate findings and final results to a report file in plans/reports/ — prevents context loss and serves as deliverable.
Evidence Gate: MANDATORY IMPORTANT MUST ATTENTION — every claim, finding, and recommendation requires file:line proof or traced evidence with confidence percentage (>80% to act, <80% must verify first).
AI Mistake Prevention — Failure modes to avoid on every task:
Re-read files after context changes. Context compaction, resume, or long-running work can make memory stale; verify current files before acting.
Verify generated content against source evidence. AI hallucinates APIs, names, claims, and document facts. Check the relevant source before documenting or referencing.
Check downstream references before deleting or renaming. Removing an artifact can stale docs, generated mirrors, configs, and callers; map references first.
Trace the full impact chain after edits. Changing a definition can miss derived outputs and consumers. Follow the affected chain before declaring done.
Verify ALL affected outputs, not just the first. One green check is not all green checks; validate every output surface the change can affect.
Assume existing values are intentional — ask WHY before changing. Before changing a constant, limit, flag, wording, or pattern, read nearby context and history.
Surface ambiguity before acting — don't pick silently. Multiple valid interpretations require an explicit question or stated assumption with risk.
Keep shared guidance role-relevant. Universal guidance must help every receiving skill or agent; code-specific obligations belong only in code-specific protocols.
Critical Thinking Mindset — Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence >80% to act.
Anti-hallucination: Never present guess as fact — cite sources for every claim, admit uncertainty freely, self-check output for errors, cross-reference independently, stay skeptical of own confidence — certainty without evidence root of all hallucination.
MUST ATTENTION apply critical + sequential thinking — every claim needs appropriate traced evidence (file:line for repo/code claims; source URL or artifact section for research, product, content, and docs claims); confidence >80% to act, <60% DO NOT recommend. Anti-hallucination: never present guess as fact, admit uncertainty freely, cross-reference independently, stay skeptical of own confidence.
MUST ATTENTION apply AI mistake prevention — verify generated content against evidence, trace downstream references before deleting or renaming, verify all affected outputs, re-read files after context loss, and surface ambiguity before acting.
Prompt-Enhance Closing Anchors
IMPORTANT MUST ATTENTION follow declared step order for this skill; NEVER skip, reorder, or merge steps without explicit user approval
IMPORTANT MUST ATTENTION for every step/sub-skill call: set in_progress before execution, set completed after execution
IMPORTANT MUST ATTENTION every skipped step MUST include explicit reason; every completed step MUST include concise evidence
IMPORTANT MUST ATTENTION if Task tools unavailable, maintain an equivalent step-by-step plan tracker with synchronized statuses
Closing Reminders
IMPORTANT MUST ATTENTION Goal: Deliver an evidence-backed viability verdict — score + confidence + Pursue/Pivot/Pause/Pass recommendation — grounded in a complete 9-block BMC, 3-year financials with stated assumptions, 5+ risks with mitigation, and a phased execution + GTM plan, so the go/no-go decision rests on traced evidence, never optimism.
MUST ATTENTION — Protocols in force (concise digest of the SYNC/shared blocks this skill carries):
- AI Mistake Prevention: verify generated content against evidence, trace downstream references, verify all affected outputs, re-read after context loss, surface ambiguity.
- Critical Thinking: traced
file:line proof, confidence >80% to act, NEVER guess as fact.
IMPORTANT MUST ATTENTION every claim, financial number, BMC block, and verdict carries evidence + confidence % (95/80/60/<60) — NEVER present a guess as fact — why: an unbacked number turns the go/no-go into optimism dressed as analysis.
IMPORTANT MUST ATTENTION bias toward skepticism on the verdict — NEVER round optimism up; surface the single key condition that must hold and the residual risk if it fails — why: a falsely-rosy Pursue burns capital that an honest Pause would save.
IMPORTANT MUST ATTENTION validate the next route with user via a direct user question — NEVER auto-decide domain-analysis/plan — why: this skill judges viability, the human owns the go/no-go.
MANDATORY IMPORTANT MUST ATTENTION break work into small todo tasks using task tracking BEFORE starting; keep one in_progress, mark completed with evidence; add a final review todo — why: untracked multi-step work loses state on compaction.
MANDATORY IMPORTANT MUST ATTENTION consume market data FROM market-analysis as evidence — NEVER re-derive market sizing here — why: this skill judges viability, it does not research the market; duplicated sizing diverges from the source.
MANDATORY IMPORTANT MUST ATTENTION all 9 BMC blocks present, each citing proof; every financial number lists its assumption + source in the assumptions table — why: a missing block or bare number is a silent gap the verdict then rests on.
MANDATORY IMPORTANT MUST ATTENTION minimum 5 risks, each with mitigation AND a residual-risk entry across market/execution/financial/competitive/regulatory/technical — why: a risk without residual pretends mitigation is total.
MANDATORY IMPORTANT MUST ATTENTION before writing any figure or claim, search market-analysis output + prior evaluations for 3+ comparable patterns and cite them — why: a number with no comparable anchor is a fabrication.
MANDATORY IMPORTANT MUST ATTENTION write the result to docs/knowledge/strategy/business/{slug}.md via the enforced .claude/templates/business-evaluation-template.md — NEVER hand-roll the structure — why: the template is the contract downstream skills (domain-analysis/plan) read.
MANDATORY IMPORTANT MUST ATTENTION persist intermediate findings to plans/reports/ for lengthy evaluations — why: external memory survives context loss and serves as the deliverable.
Anti-Rationalization:
| Evasion | Rebuttal |
|---|
| "Idea is obviously viable, skip rigor" | Optimism is not evidence. Run all 9 blocks + financials + risks anyway. |
| "Skip a BMC block — not relevant" | Every block cites proof or states why N/A explicitly; silent omission fails the gate. |
| "Estimate the number, source it later" | No assumption + source = no number. Fill the assumptions table before the verdict. |
| "5 risks is a lot, 2 covers it" | Minimum 5, each with residual risk. Thin risk lists hide the real downside. |
| "Recommendation is clear, skip the ask" | Still a direct user question for the next route — the human owns go/no-go. |
IMPORTANT MUST ATTENTION evidence + confidence % on every number — NEVER present a guess as fact. IMPORTANT MUST ATTENTION bias toward skepticism — NEVER round optimism up. IMPORTANT MUST ATTENTION a direct user question for the next route — NEVER auto-decide.
Hookless Prompt Protocol Mirror (Auto-Synced)
Source: .claude/.ck.json + .claude/skills/shared/sync-inline-versions.md (:full blocks) + .claude/scripts/lib/hookless-prompt-protocol.cjs
[WORKFLOW-EXECUTION-PROTOCOL] [BLOCKING] Workflow Execution Protocol — MANDATORY IMPORTANT MUST CRITICAL. Do not skip for any reason.
Generic portability boundary: Reusable skills and protocol text stay project-neutral; project-specific conventions are discovered from docs/project-config.json and docs/project-reference/. Apply shared AI-SDD from shared/sdd-artifact-contract.md. Read docs/project-config.json and docs/project-reference/docs-index-reference.md, then open the project reference docs named there. For spec, test-case, behavior-change, public-contract, or docs/specs/ work, route through the local spec docs named by the docs index: feature-spec-reference.md, spec-system-reference.md, spec-principles.md, and workflow-spec-test-code-cycle-reference.md when specs/tests/code must stay synchronized. If either file or a required reference doc is missing or stale, auto-run $project-init (or the narrow lower-level route such as $project-config, $docs-init, $scan-all, or $scan --target=<key>) before ordinary project-specific work. Any supported AI tool may execute when this shared context and local docs are available.
- DETECT: If the prompt starts with an explicit slash skill/workflow command, execute it directly. Otherwise match the prompt against the workflow catalog and skill list.
- ANALYZE: Choose the best option: execute directly, invoke a skill, activate a standard workflow, or compose a custom step combination.
- AUTO-SELECT: Pick the best option yourself. Do not ask the user to choose between direct execution, skill, standard workflow, or custom workflow.
- ACTIVATE: For a selected workflow, call
$start-workflow <workflowId>; for a selected skill, invoke that skill; for a custom workflow, sequence custom steps directly; for direct execution, proceed with the task.
- CREATE TASKS: task tracking for ALL workflow/skill/custom steps before execution when the selected path has multiple steps.
- EXECUTE: Advance per the Workflow Step Advancement & Parallel Phases rule in your context instructions — model-driven; a sub-agent completion advances a step identically to an inline call; a parallel-phase group is an all-return barrier (advance only after ALL members return, never serialize it)
Shared AI-SDD Protocol Markers
Source: .claude/skills/shared/sync-inline-versions.md
SYNC:ai-sdd-artifact-contract
AI-SDD Artifact Contract — Shared spec-driven development rules stay portable and source-owned.
- Keep reusable AI-SDD principles in
.claude; put repository-specific paths, commands, owners, products, and formats in project config/reference docs.
- Preserve cycle:
spec -> plan -> tasks -> implement -> verify -> update spec/docs.
- Trace every requirement or invariant through decision, task, TC/test, source evidence, and docs/spec update.
- Treat code-to-spec extraction as reference-only until accepted by the canonical spec owner.
- Any supported AI tool may plan, implement, review, or verify with synced context; using multiple tools is optional.
- Update
.claude source first, then sync generated mirrors; do not manually edit .agents, .codex, or AGENTS.md. — why: mirrors are generated artifacts; hand-edits are overwritten on the next sync
- If
docs/project-config.json, root instruction files, or a required project-reference doc is missing or stale, auto-run $project-init or the narrow lower-level route before ordinary project-specific work.
Active reference: shared/sdd-artifact-contract.md in the active skills root.
SYNC:ai-sdd-artifact-contract:reminder
- MANDATORY Apply
shared/sdd-artifact-contract.md; keep reusable AI-SDD in .claude and local rules in project docs.
- MANDATORY Code-to-spec extraction is reference-only until canonical acceptance; any supported AI tool may execute with synced context.
- MANDATORY Update
.claude source before syncing generated mirrors; do not manually edit .agents, .codex, or AGENTS.md.
- MANDATORY Missing or stale project config, root instruction files, or required reference docs route project-specific work through
$project-init or the narrow setup route automatically.
[TASK-PLANNING] [MANDATORY] BEFORE executing any workflow or skill step, create/update task tracking for all planned steps, then keep it synchronized as each step starts/completes.
[LESSON-LEARNED-REMINDER] [BLOCKING] Task Planning & Continuous Improvement — MANDATORY. Do not skip.
Break work into small tasks (task tracking) before starting. Add final task: "Analyze AI mistakes & lessons learned".
Extract lessons — ROOT CAUSE ONLY, not symptom fixes:
- Name the FAILURE MODE (reasoning/assumption failure), not symptom — "assumed API existed without reading source" not "used wrong enum value".
- Generality test: does this failure mode apply to ≥3 contexts/codebases? If not, abstract one level up.
- Write as a universal rule — strip project-specific names/paths/classes. Useful on any codebase.
- Consolidate: multiple mistakes sharing one failure mode → ONE lesson.
- Recurrence gate: "Would this recur in future session WITHOUT this reminder?" — No → skip
$learn.
- Auto-fix gate: "Could
$code-review/$code-simplifier/$security-review/$lint catch this?" — Yes → improve review skill instead.
- BOTH gates pass → ask user to run
$learn.
[CRITICAL-THINKING-MINDSET] Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence >80% to act.
Anti-hallucination principle: Never present guess as fact — cite sources for every claim, admit uncertainty freely, self-check output for errors, cross-reference independently, stay skeptical of own confidence — certainty without evidence root of all hallucination.
AI Attention principle (Primacy-Recency): Put the 3 most critical rules at both top and bottom of long prompts/protocols so instruction adherence survives long context windows.
Goal-driven execution: Define success criteria first, loop until verified, and stop only when observable checks pass.
Tests verify intent: Tests must protect business rules/invariants and fail when the protected intent breaks, not only mirror current behavior.
Common AI Mistake Prevention (System Lessons)
- Re-read files after context compaction. Edit requires prior Read in same context; compaction wipes read state. Re-read before editing.
- Grep for old terms after bulk replacements. AI over-trusts find/replace completeness. Grep full repo after bulk edits for missed refs in docs/configs/catalogs.
- Check downstream references before deleting. Deletions cascade doc/code staleness. Map referencing files before removal.
- After memory loss, check existing state before creating new. Compaction wipes prior-work memory. Query current state to resume — never blindly duplicate.
- Verify AI-generated content against actual code. AI hallucinates APIs, class names, method signatures. Grep to confirm existence before documenting/referencing.
- Trace full dependency chain after edits. Changing a definition misses downstream consumers. Trace the full chain.
- When renaming, grep ALL consumer file types. Some file types silently ignore missing refs (no compile error). Search code, templates, configs, generated files.
- Trace ALL code paths when verifying correctness. Code existing ≠ code executing. Trace early exits, error branches, conditional skips — not just happy path.
- Update docs that embed canonical data when source changes. Docs inlining derived data (workflows, schemas, configs) go stale silently. Update all embedding docs alongside source.
- Verify sub-agent results after context recovery. Background agents may finish while parent compacted — grep-verify output, don't trust assumed completion.
- Cross-check full target list against sub-agent assignments. Parallel sub-agents by category miss boundary items. Reconcile union of assignments against target list before proceeding.
- Sub-agents inherit knowledge only from their agent .md definition — use custom agent types, not built-in Explore. Tool adoption = permission + knowledge + enforcement (numbered workflow step).
- Persist sub-agent findings incrementally, not as a final batch. Long sub-agents hit cutoffs before final write — findings lost. Instruct append-per-section to report file.
- When debugging, ask "whose responsibility?" before fixing. Trace caller (wrong data) vs callee (wrong handling). Fix at responsible layer — never patch symptom site.
- Grep ALL removed names after extraction/refactoring. Primary file "done" ≠ secondary files clean. Grep entire scope for every removed symbol before declaring complete.
- Assume existing values are intentional — ask WHY before changing. Pattern-matching as "wrong" skips context. Before changing any constant/limit/flag: read comments, git blame, surrounding code.
- Verify ALL affected outputs, not just the first. One build green ≠ all green. Multi-stack changes (backend/frontend/tests/docs) require verifying EVERY output.
- Evaluate fit before copying a nearby pattern. Closest example ≠ matching preconditions — verify the new context shares the same constraints, base classes, scope, lifetime.
- Holistic-first debugging — resist nearest-attention trap. Don't dive into first plausible cause. List EVERY precondition (config, env vars, paths, DB, endpoints, creds, versions, DI, data). Verify each against evidence (grep/query — not reasoning). Ask "what would falsify this?" — if nothing, it's not a hypothesis. Most expensive failure: going deeper in "obvious" layer while bug sits in layer never questioned.
- Surgical changes — apply the diff test (context-aware). Two modes: (1) Bug fix → every line traces to the bug; no restyling; orphan cleanup only for imports YOUR changes made unused. (2) Review/enhancement → implement improvements AND announce as "Enhancement beyond main request: [what]". Never silently scope-creep. Diff test: "Would this line exist if I wasn't asked to do X?" — if no, delete or announce.
- Surface ambiguity before coding — don't pick silently. Multiple valid interpretations → present each with effort: "[Request] could mean (1) [N h], (2) [N h]. Which matters?" List scope/format/volume/constraints assumptions first. If simpler path exists, say so. Never silently pick.
- [MANDATORY FIRST ACTION] ALWAYS activate a suitable skill or workflow BEFORE responding. Match task against workflow catalog + skill list; invoke via skill invocation or
$start-workflow <workflowId>. NEVER answer or write code before checking. Skip = protocol violation.
- Why-Review adversarial mindset — apply when reviewing any plan, decision, or design. Default SKEPTIC not VALIDATOR: steel-man a rejected alternative, invert each stated reason ("what does it sacrifice?"), stress-test top 2-3 assumptions, run pre-mortem ("ships, fails in 3 months — what breaks?"), surface 1-2 alternatives author missed. Section presence ≠ quality; quality = causal reasoning + concrete mitigations + evidence, not "it's better" or "monitor closely".
- Front-load report-write in sub-agent prompts for large reviews. Many-file sub-agents hit budget before final write — findings lost. Design prompts so: (1) report-write is first explicit deliverable, (2) append per-file/section (not batched), (3) scope bounded so reads don't exhaust budget. Truncated mid-sentence with no report file → spawn narrower scope, don't retry same prompt.
- After context compaction, re-verify all prior phase outcomes before continuing. Summaries describe intent, not environment state (git index, filesystem, processes). On resume, FIRST audit: git status, re-read modified files, verify filesystem. Every "completed" claim is an untested hypothesis until evidence confirms.
- OOM/memory: check row count before row size. Triage: (1) Unbounded query — no DB filter for trigger? Push filter to DB; eliminates OOM. (2) Large rows? Projection reduces proportionally. Row reduction > projection in ROI.
- Keep domain concepts out of generic/shared/infrastructure layers. Reusable layer (shared library, framework, infra module) must reference NO consumer-specific domain concept — tenant/customer/product IDs, business entities, feature rules. Leak compiles + runs → passes review silently while coupling the "reusable" layer to one consumer. Keep shared type domain-free; push domain fields/logic down into the consumer via subclass/composition. — why: a layer coupled to one consumer's domain is no longer reusable.
