| name | business-logic-guardian |
| description | Use ONLY when a business-logic doc exists — docs/<app>/business-logic-index.md (AI-default retrieval index), docs/<app>/business-logic.md (human narrative), or docs/en/business-logic.md (the app-business-docs canonical for Fusebase CLI teams) — before fixes/improvements that touch business behavior. Treats the documented business logic as a guard layer — the fix must not silently break documented behavior. Pairs with FR-20 zoom-out. If none of these docs exist, this skill does nothing (silent no-op) — do NOT auto-create any of them. Not for net-new features with no documented logic. |
| source_inspiration | conceptual-only |
| license_status | clean-room-original |
| fusebase_flow_version | 3.5 |
| risk_level | low |
| invocation | automatic |
| expected_outputs | ["a business-logic impact check for the change in progress","a flag when a fix would break documented behavior"] |
| related_workflows | ["eight-phase-flow.md","verification-gate.md"] |
| hook_dependencies | ["none"] |
Business Logic Guardian
Style: Mode-B-lite. Artifact-gated — inert unless a business-logic doc exists at ANY path in § Doc-path resolution.
Purpose
Protect documented business logic during fixes and improvements. The business-logic doc is a fast navigation/verify layer: confirm a change does not silently break documented behavior before committing. Complements FR-20 (zoom-out) and FR-10 (reproduce-before-fix).
Consumes whichever business-logic doc exists. Per FR-23 (flow-skills/documentation-budget/SKILL.md), the AI-default authoring format is the retrieval index templates/business-logic-index.md (tables + source paths); the narrative templates/business-logic.md is the explicit human-readable option. This skill reads either as the guard layer.
Doc-path resolution (the gate checks ALL of these)
| Doc | Path | Role |
|---|
| Retrieval index (AI-default, FR-23) | docs/<app>/business-logic-index.md | primary guard layer when present |
| Flow narrative (human option) | docs/<app>/business-logic.md | guard layer; supplementary if index exists |
CLI-edition narrative (app-business-docs canonical) | docs/en/business-logic.md | guard layer for Fusebase CLI teams using the provider skill |
If several exist: index first, narratives supplementary. The gate no-ops only when none of the three exists.
When to invoke
- Any doc in § Doc-path resolution exists —
docs/<app>/business-logic-index.md (AI-default), docs/<app>/business-logic.md, or docs/en/business-logic.md (app-business-docs canonical) — AND a fix/improvement touches business behavior. If several exist, the index is the primary guard layer; narratives are supplementary.
- Operator says "don't break the business logic", "does this change behavior".
- During Implement / post-gate fixes on an app that has documented logic.
Do not invoke when
- None of the § Doc-path resolution paths exists (
docs/<app>/business-logic-index.md, docs/<app>/business-logic.md, docs/en/business-logic.md) → silent no-op; do not create any of them (author deliberately via app-business-docs — which writes docs/en/business-logic.md — or the FR-23 business-logic-index template).
- Net-new feature with no documented logic yet.
- Pure cosmetic edits.
Required inputs
| Input | Where it lives | If missing |
|---|
| Business logic doc | any § Doc-path resolution path: docs/<app>/business-logic-index.md / docs/<app>/business-logic.md / docs/en/business-logic.md | STOP — no-op only if ALL three absent. Author via app-business-docs (→ docs/en/business-logic.md) or the FR-23 index template if wanted. |
| The change in progress | current diff/plan | nothing to check; exit |
Procedure
- Existence gate (FIRST STEP). Check ALL § Doc-path resolution paths:
docs/<app>/business-logic-index.md, docs/<app>/business-logic.md, docs/en/business-logic.md. None exists → exit silently; do not create any. At least one exists → it is the guard layer (index primary).
- Read the documented business logic / main flows / edge cases.
- Impact-check. Does the change alter, remove, or contradict any documented behavior or edge case?
- Verify against code — the doc is the navigation layer; confirm the actual code path matches before trusting the doc (code is source of truth).
- Compute and emit the Required output block below using the impact answer and code verification.
- Flag any documented behavior the change would break; recommend preserving it or, if the change is intentional, updating the doc (via
app-business-docs) in the same change.
- Ambiguity → ask operator (FR-19).
Worked example
Change: allow editing approved invoices; BL-7 says approved invoices are immutable. Code check: src/invoices/service.ts:updateInvoice() enforces the lock.
Business logic: Drift
Guard source: docs/billing/business-logic-index.md — BL-7
Code check: src/invoices/service.ts:updateInvoice() — matches doc
Action: preserve behavior
Required output — business-logic impact verdict (4 lines)
Every activation that reaches step 3 MUST emit this block after step 4's code verification, in chat and verbatim into the gate/ticket note when one is written. An impact-check claim without the block is unverifiable and does not count as a check.
Business logic: <Preserved | Drift | Blocked (intent unclear, FR-11)>
Guard source: <business-logic doc path + rule/flow/edge-case identifier>
Code check: <source path/symbol — matches doc | doc stale | behavior differs>
Action: <proceed | preserve behavior | update doc in same change | question for operator (FR-19)>
Output artifacts
| Artifact | Location | Mode |
|---|
| Business-logic impact verdict block (4 lines, above) | chat / gate note | Mode A / Mode-B-lite |
Failure cases
| Failure | Detection | Response |
|---|
| Artifact absent | step 1 | silent no-op (correct) |
| Change breaks documented behavior | step 3 | flag; preserve or update-doc-in-same-change |
| Doc disagrees with code | step 4 | trust code; note the doc is stale; suggest refresh |
Escalation path
- Intentional behavior change → update whichever guard doc is in use in the same change (narratives via
app-business-docs, which maintains docs/en/business-logic.md; the index via the FR-23 business-logic-index template).
- Conflict with a locked decision → ask operator (FR-11/FR-19).
Anti-patterns
- Do not activate/create the doc when absent.
- Do not trust the doc over the code (verify).
- Do not silently change documented behavior without flagging it.
Clean-room note
Original Fusebase Flow content. See docs/source-map.md. No third-party code, prompts, or skill files copied.
