Purpose
This is the structure for a use case document. It is written by us. It describes what we are building, how it works, what it depends on, and what the critical path to delivery looks like.
It is not a questionnaire. It does not ask anyone to fill anything in.
Field Classification
| Marker | Meaning |
|---|---|
| [M] | MANDATORY -- requires confirmed information from client or domain research. Cannot be invented. |
| [D] | DERIVED -- UV proposes based on experience. Client confirms or corrects. |
Section 01 -- Overview [M]
All fields mandatory. This is the identity of the project.
| Field | Value |
|---|---|
| Use Case ID | UC-XX |
| Client Reference [M] | Client's own project code / PO number / tracking ID |
| System Name [M] | |
| Domain [M] | |
| One-Line Description [M] | |
| Status [M] | Kickoff / In Development / UAT / Production |
| Target Delivery [M] |
Summary [M]
What the system does and why it exists. 2-3 paragraphs. No implementation detail.
Section 02 -- Actors [M]
Roles must come from confirmed understanding of who uses the system.
| Role [M] | Description [M] | Access Level [D] | Frequency [D] |
|---|---|---|---|
| What this person does in the business | What they can see and do -- UV proposes | UV estimates based on role |
Section 03 -- User Stories [M/D]
Stories are written by UV based on understood requirements. Priority assigned by UV, confirmed by client.
Grouped by actor. Priority: P1 (must), P2 (should), P3 (could), P4 (won't this phase).
Actor: [Role]
- P1 [M]: As a [Role], I want to [action], so that [outcome].
- P2 [D]: ...
P1 stories must be confirmed. P2-P4 can be proposed by UV.
Section 04 -- System Flows [M/D]
Flow triggers and happy paths are mandatory (confirmed). Exception handling and SLAs can be derived.
One subsection per workflow.
Flow: [Name] [M]
Trigger [M]: What starts this flow.
| # | Step [M] | Actor [M] | Input [M] | Output [D] | Decision [M] |
|---|---|---|---|---|---|
| 1 |
Result [M]: End state when flow completes.
Exceptions [D]: What happens on failure, rejection, timeout. UV proposes standard handling.
SLA [D]: Maximum time from trigger to completion. UV proposes based on flow type.
Volume [M]: Expected frequency. Must be confirmed (drives architecture).
Section 05 -- Data Model [M/D]
Entities and their key fields are mandatory. Field types, validation rules, and lifecycle states can be derived from domain patterns.
Entities
| Entity [M] | Description [M] | Key Fields [M] | States [D] | Relationships [D] |
|---|---|---|---|---|
| What it represents | Unique identifiers | UV proposes lifecycle | UV infers from entity graph |
Business Rules [M/D]
| ID | Rule [M] | Trigger [D] | On Violation [D] |
|---|---|---|---|
| BR-01 | The rule itself must be confirmed | When it fires -- UV proposes | Response -- UV proposes |
Rules themselves are mandatory (business logic cannot be invented). Implementation triggers and violation responses can be derived.
Section 06 -- Screens [D]
Entire section is derived. UV proposes screen layout based on actors, flows, and data model. Client confirms or adjusts.
| Screen [D] | Actor [M] | Purpose [D] | Key Elements [D] |
|---|---|---|---|
| Confirmed from Section 02 | UV proposes | UV proposes |
Wireframes or mockups attached where available.
Section 07 -- Integrations [M]
All integration points are mandatory. Cannot be guessed -- must be confirmed what systems exist and what data moves.
| System [M] | Direction [M] | Data [M] | Format [D] | Frequency [M] | Fallback [D] |
|---|---|---|---|---|---|
| In / Out / Both | What is exchanged | UV proposes (API preferred) | Must be confirmed | UV proposes retry/queue |
Section 08 -- Infrastructure [D]
Entire section is derived unless client has hard constraints. UV proposes stack based on requirements.
| Layer | Choice [D] | Reason [D] |
|---|---|---|
| Hosting | UV proposes | |
| Database | UV proposes | |
| Frontend | UV proposes | |
| Runtime | UV proposes |
Constraints [M]
Hard limits that override UV proposals. Only include confirmed constraints.
- Data residency requirements (if any)
- Mandated technology (if any)
- Compliance frameworks (if any)
If none confirmed, state "No hard constraints confirmed."
Environments [D]
UV proposes standard setup. Client confirms.
| Environment | Purpose |
|---|---|
| Development | Build and test |
| UAT | Acceptance testing |
| Production | Live |
Section 09 -- Critical Path [D]
Derived by UV based on dependency analysis of sections above. Client confirms timeline is acceptable.
| # | Item [D] | Depends On | Duration [D] | Blocker Risk [D] |
|---|---|---|---|---|
| 1 | -- | |||
| 2 | #1 | |||
| 3 | #2 |
Parallel Work (off critical path) [D]
| Item | Can Start After | Duration |
|---|---|---|
Milestones [D]
| Milestone | Reached When | Target Date |
|---|---|---|
| M1: Core flow operational | First end-to-end with real data | |
| M2: UAT ready | All P1 stories deployed to UAT | |
| M3: Go-live | Sign-off, production deployed |
Section 10 -- What Is Needed [M]
Items that must be obtained before work proceeds. All mandatory -- this is the blocker list.
| # | Item [M] | From [M] | Blocking [M] | Status [M] |
|---|---|---|---|---|
| 1 | Yes/No | Open / Received |
Section 11 -- Acceptance Criteria [M/D]
Definition of Done [D]
UV proposes standard criteria. Client confirms what constitutes acceptance.
| Criterion [D] | Verified By [D] |
|---|---|
| All P1 stories implemented | UAT pass |
| Business rules enforced | Test per BR-XX |
| Integrations operational | End-to-end with real data |
| Performance within SLA | Load test |
| Security review | Pen test / code review |
Success Metrics (30/60/90 days) [M]
Must be confirmed -- these define whether the project succeeded.
| Metric [M] | Target [M] | Measured By [D] |
|---|---|---|
Section 12 -- Risks [D]
UV identifies risks based on analysis. Standard risk management.
| # | Risk [D] | Likelihood [D] | Impact [D] | Mitigation [D] |
|---|---|---|---|---|
| R1 | H/M/L |
Open Questions [M]
Questions that remain unanswered. These are mandatory to document -- unknown unknowns must be surfaced.
| # | Question [M] | Impacts [D] | Resolution [M] |
|---|---|---|---|
| Q1 | UV explains impact | Must be answered |
Section 13 -- Cooperator Brief [D]
Entirely derived by UV. This is our internal handoff to the developer.
| Field | Value |
|---|---|
| Scope [D] | What exactly is being built |
| Stack [D] | Confirmed technology |
| Timeline [D] | Milestones with dates |
| Dependencies [D] | What must exist before work starts |
| Interfaces [D] | What is received and what is delivered |
| Quality Bar [D] | Test coverage, review process, documentation |
| Handover [D] | Artefacts delivered at completion |
Classification Summary
| Section | Classification | Notes |
|---|---|---|
| 01 Overview | Mandatory | Cannot proceed without this |
| 02 Actors | Mandatory | Must know who uses it |
| 03 User Stories | Mixed | P1 mandatory, rest derived |
| 04 System Flows | Mixed | Triggers/steps mandatory, error handling derived |
| 05 Data Model | Mixed | Entities mandatory, lifecycle/validation derived |
| 06 Screens | Derived | UV proposes entirely |
| 07 Integrations | Mandatory | Must know what connects to what |
| 08 Infrastructure | Derived | UV proposes unless hard constraints exist |
| 09 Critical Path | Derived | UV calculates from dependencies |
| 10 What Is Needed | Mandatory | Blocker list |
| 11 Acceptance | Mixed | Success metrics mandatory, criteria derived |
| 12 Risks | Derived | UV identifies from analysis |
| 13 Cooperator Brief | Derived | Internal UV document |
Version History
| Version | Date | Changes |
|---|---|---|
| UCT-3.1 | 2026-05-02 | Added [M]/[D] classification to all fields. Classification summary table. |
| UCT-3.0 | 2026-05-02 | Rewrite: solution description by UV. Critical path. No questionnaire. |
| UCT-2.0 | 2026-05-02 | Stakeholder questionnaire (deprecated) |
| UCT-1.0 | 2026-05-02 | Nexus-internal spec (deprecated) |