Interface Design
Template Library
Interface Design Template
Define interface contracts, validation rules, authorization, error behavior, evidence produced, compatibility expectations, and downstream verification needs.
ES-105
Interfaces
Contracts
Template purpose
Use this template to define the interfaces that connect users, components, services, workflows, external systems, AI capabilities, and evidence stores.
An interface design should be explicit enough that implementation and testing teams understand inputs, outputs, validation, authorization, error behavior, evidence, compatibility, and ownership.
Project
<Project name>
Document control
| Field |
Value |
| Artifact owner |
<owner> |
| Primary reviewers |
<reviewers> |
| Status |
<draft / in review / accepted / revised> |
| Last updated |
<YYYY-MM-DD> |
| Related Engineering Stage |
ES-105 — Detailed Design |
| Project workspace target |
docs/project-workspace/design/interface_design.md |
Interface register
| ID |
Interface |
Caller |
Provider |
Purpose |
Inputs |
Outputs |
Authorization |
Evidence Produced |
| IF-001 |
<interface> |
<caller> |
<provider> |
<purpose> |
<inputs> |
<outputs> |
<auth rule> |
<evidence> |
Interface details
IF-001 — <Interface Name>
| Field |
Value |
| Purpose |
<purpose> |
| Caller |
<caller> |
| Provider |
<provider> |
| Interaction Type |
<UI / API / event / file / database / message / AI interaction / manual handoff> |
| Related Requirements |
<FR/NFR/C IDs> |
| Related Components |
<components> |
| Owner |
<owner> |
<input fields / payload / request / event / user action>
Output contract
<output fields / response / event / confirmation / evidence>
Validation rules
| Rule ID |
Rule |
Failure Behavior |
| VAL-001 |
<rule> |
<failure behavior> |
Authorization rules
| Action |
Required Role / Condition |
Denied Behavior |
<action> |
<role or condition> |
<denied behavior> |
Error behavior
| Error |
Response |
Evidence / Log |
<error> |
<response> |
<evidence> |
Evidence produced
| Evidence |
Trigger |
Storage / Review |
<evidence> |
<trigger> |
<location or review> |
Compatibility and versioning
<Versioning, backward compatibility, migration, or deprecation considerations.>
Security and privacy considerations
<Access control, data minimization, sensitive fields, privacy, logging restrictions.>
Test implications
<Tests, contract checks, integration checks, or review evidence needed.>
Open interface questions
| ID |
Question |
Owner |
Needed By |
| IFQ-001 |
<question> |
<owner> |
<date or stage> |
Review checklist
- [ ] Interfaces have owners.
- [ ] Inputs and outputs are defined.
- [ ] Validation rules are explicit.
- [ ] Authorization rules are explicit.
- [ ] Error behavior is defined.
- [ ] Evidence produced is identified.
- [ ] Security and privacy concerns are considered.
- [ ] Test implications are identified.
Continue to Data Design
Define entities, fields, relationships, evidence fields, access restrictions, and retention.
Open Data Design →