Writing a Technical Requirements Document that designs the technical architecture of the system or feature: components and boundaries, data flow, integration points, failure modes, and the mandatory program structure (DDD/hexagonal source tree) — in technology-agnostic patterns (code structure excepted), plus auth/pagination and BFF contracts for fullstack. Gate 3 of ring:planning-large-features (after ring:mapping-feature-relationships, before ring:designing-api-contracts) and Gate 2 of ring:planning-small-features (after ring:writing-prds, before ring:writing-plans). Use when the PRD passed validation. Skip when the PRD is unvalidated or the architecture is already documented.
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Writing a Technical Requirements Document that designs the technical architecture of the system or feature: components and boundaries, data flow, integration points, failure modes, and the mandatory program structure (DDD/hexagonal source tree) — in technology-agnostic patterns (code structure excepted), plus auth/pagination and BFF contracts for fullstack. Gate 3 of ring:planning-large-features (after ring:mapping-feature-relationships, before ring:designing-api-contracts) and Gate 2 of ring:planning-small-features (after ring:writing-prds, before ring:writing-plans). Use when the PRD passed validation. Skip when the PRD is unvalidated or the architecture is already documented.
TRD Creation — Architecture Before Implementation
When to use
PRD passed Gate 1
Feature Map passed Gate 2 (Large Track only)
About to design technical architecture
Skip when
PRD not validated → complete Gate 1 first
Architecture already documented → proceed to API Design (Large) or plan (Small)
The TRD designs the technical architecture of the system or feature: components and their boundaries, data flow between them, integration points, and failure modes — using technology-agnostic patterns before concrete technology choices.
Handling Missing Information
When specific details are not provided (tech stack, architecture, team size, deployment model, etc.):
Infer from project name, context, existing codebase patterns, and git history
Document assumptions explicitly in a ## Assumptions section at the top of the TRD
NEVER block execution to ask clarifying questions — assume and proceed
Flag assumptions that carry high risk for the reader to validate (mark as ⚠️ Assumption:)
The only valid exception: tech stack ambiguity in Step 0 when auto-detection fails and no codebase files exist to infer from
Step -1: Design Validation Check (UI Features Only, Conditional)
Read PRD and detect UI indicators (user stories with "see", "view", "click", "page", "screen", "button", "form"; features involving login, dashboard, settings, reports, notifications).
If feature has UI:
Check docs/pre-dev/{feature}/design-validation.md (produced by a standalone ring:validating-ux-completeness run, if one happened)
If present → honor its verdict: "DESIGN VALIDATED" proceeds; any other verdict means fix the listed design gaps before (or alongside) the TRD
If absent → proceed and add to ## Assumptions: ⚠️ UX risk: no design validation ran for this UI feature — consider a standalone ring:validating-ux-completeness pass
If backend-only: Skip to Step 0.
Step 0: Tech Stack Definition (HARD GATE)
Step 0.1: Auto-Detect or Ask
go.mod exists → Go
package.json with react/next → Frontend TS
package.json with express/fastify/nestjs → Backend TS
Ambiguous → AskUserQuestion: "What is the primary technology stack?"
Step 0.2: Load Ring Standards via WebFetch
Tech Stack
Standards to Load
Go Backend
golang/index.md + devops.md + sre.md
TypeScript Backend
typescript.md + devops.md + sre.md
TypeScript Frontend
frontend.md + devops.md
Full-Stack TypeScript
typescript.md + frontend.md + devops.md + sre.md
WebFetch base URL: https://raw.githubusercontent.com/LerianStudio/ring/main/dev-team/docs/standards/
Step 0.3: Read PROJECT_RULES.md
Check: docs/PROJECT_RULES.md → docs/STANDARDS.md (legacy) → if neither exists, note the absence and proceed with Ring standards.
Step 0.4: Analyze PRD and Suggest Technologies
Read PRD, extract requirements, suggest technologies per category, confirm with user.
TRD header must include: feature, gate: 3 (Large) / gate: 2 (Small), deployment.model, tech_stack.primary, tech_stack.standards_loaded[], project_technologies[] (category, prd_requirement, choice, rationale per decision). On Large Track this flows to Gates 4–6.
Choose style (Microservices, Modular Monolith, Serverless); design components with explicit boundaries; define interfaces; model data flow end-to-end; plan integration points and patterns; design security; produce Program Design — bounded contexts (vertical slices) + source tree (see section below)
3. Failure Modes
For each component and integration point: what fails, how it is detected, how the system degrades or recovers (timeout/retry/circuit-break/fallback); consistency under partial failure
4. Gate Validation
All domains mapped; component boundaries clear; interfaces technology-agnostic; data ownership explicit; failure modes covered; quality attributes achievable; no specific products named
Program Design (Code Structure — MANDATORY)
Every TRD MUST include a ## Program Design section with two mandatory parts: (1) the bounded contexts / vertical slices the feature creates or touches, and (2) the source tree for each. This anchors implementation to Lerian's mandatory modeling — Modular Monolith + DDD + Hexagonal (ports & adapters) + CQRS-light — as shipped in the canonical go-boilerplate-ddd. It is the one place a TRD is concrete about code structure; it stays silent on product choices (see exception note under Technology Abstraction Rules).
Part 1 — Bounded Contexts (Vertical Slices) [MANDATORY]
In the Lerian model a vertical slice = bounded context = one internal/{context}/ module that owns its full stack top to bottom (adapters → ports → services → domain). Identifying them is the highest-leverage modeling decision and the most expensive to get wrong, so the TRD MUST make it explicit before any code is written.
Enumerate every context the feature creates or touches:
Context
New / Existing
Responsibility (ubiquitous language)
Owns (entities / tables)
Talks to (via port)
{context}
New
one-line bounded responsibility
entities + tables it owns
other contexts / external capabilities
Slicing rules:
Fewest contexts that hold. Extend an existing context by default; create a new one ONLY when the feature introduces a genuinely distinct ubiquitous language / ownership boundary. No speculative contexts.
One context owns its data. Cross-context access goes through ports/, never by reaching into another context's tables.
Large Track: contexts MUST be consistent with feature-map.md## Phases — a phase may deliver one or more contexts; a context never straddles unrelated phases. Small Track: this table is the first place contexts are defined.
Part 2 — Source Tree [MANDATORY]
When tech_stack.primary is Go: render EACH context from Part 1 using the canonical slice layout. Replace {context} with the real bounded-context name (never ship example — that is the boilerplate's teaching scaffold).
internal/{context}/
├── adapters/
│ ├── http/ # driving adapter — thin Huma/HTTP handlers (parse, validate, call service)
│ ├── m2m/ # driving adapter — machine-to-machine (only if service-to-service auth)
│ └── postgres/ # driven adapter — persistence via lib-commons (libPostgres); no raw sql.Open
├── domain/
│ └── entities/ # entities + value objects; pure domain, imports no infrastructure
├── ports/ # interfaces only — driving (service contracts) + driven (repos / gateways)
├── services/
│ ├── command/ # CQRS write side — use cases that mutate state
│ └── query/ # CQRS read side — use cases that read state
├── streaming/ # event producers / consumers (Event-Driven profile only)
└── mocks/ # generated mocks for the ports
Shared/platform code lives OUTSIDE the slice — reference only what the feature touches:
Path
Role — and the slice's constraint
cmd/app/main.go
process entry point — slice does not touch it
internal/bootstrap/
composition root (config, telemetry, DB, auth, route wiring, lifecycle) — register routes/wiring here; a slice NEVER bootstraps its own logger/DB/telemetry
internal/shared/
service-specific shared code — reuse, but never duplicate lib-commons/lib-observability/lib-systemplane/lib-streaming features
migrations/
SQL migrations (golang-migrate) — add the feature's migration here
docs/openapi.yaml
committed OAS 3.1 spec (generated) — regenerate after any API-surface change
Modeling rules to state alongside the tree:
Dependencies point inward: adapters → ports ← services → domain. domain imports no infrastructure.
Interfaces in ports/, implementations in adapters/.
Keep handlers thin; infrastructure concerns stay in bootstrap, never in the slice.
tenantId derives from validated request identity — never from JSON payload or path params.
When tech_stack.primary is not Go: mirror the project's equivalent canonical layout (or the existing module structure detected in the repo) and state the same context boundaries, dependency direction, and ports/adapters split. Do not invent a structure the codebase does not already use.
Technology Abstraction Rules
Element
Say This (✅)
Not This (❌)
Database
"Relational Database"
"PostgreSQL 16"
Cache
"In-Memory Cache"
"Redis" or "Valkey"
Message Queue
"Message Broker"
"RabbitMQ"
Object Storage
"Blob Storage"
"MinIO" or "S3"
Web Framework
"HTTP Router"
"Fiber" or "Express"
Auth
"JWT-based Authentication"
"specific library"
TRD never includes: product names with versions, package manager commands, cloud service names (RDS, Lambda), framework-specific terms, container/orchestration specifics, CI/CD tool names.
Exception — Program Design: the ## Program Design section IS concrete about code structure (layer and adapter folder names that mirror the mandatory boilerplate). Those names describe modeling slots, not product couplings — adapters/postgres/ is the persistence-adapter slot, not a PostgreSQL-version dependency. The abstraction rules above govern product/capability choices (DB engine, broker, cache); they never apply to the code-modeling tree.
HARD RULE: Client-side code MUST NEVER call backend APIs directly. api_pattern: direct does not exist for dynamic data.
Design System Configuration (UI Features)
Auto-detect from package.json: @your-org/design-system (your design-system package, if any), @radix-ui/*, @shadcn/ui, @chakra-ui/*, @mui/material, etc.
TRD must include ## Design System Configuration section:
Document in TRD: API Patterns → Pagination → Strategy + Rationale
ADR Template
**ADR-00X: [Pattern Name]**-**Context**: [Problem needing solution]
-**Options**: [List with trade-offs - no products]
-**Decision**: [Selected pattern]
-**Rationale**: [Why this pattern]
-**Consequences**: [Impact of decision]
Gate Validation Checklist (Gate 3 Large / Gate 2 Small)
Category
Requirements
Architecture Completeness
All PRD features mapped; DDD boundaries; clear responsibilities; stable interfaces
Program Design
Bounded contexts (vertical slices) enumerated (new vs existing); source tree present per context, mirroring DDD+Hexagonal+CQRS boilerplate; {context} named (never example); dependency direction stated; ports/adapters split correct; Large Track consistent with feature-map Phases
Data Design
Ownership explicit; models support PRD; consistency strategy; flows documented end-to-end
Failure Modes
Each component and integration point has failure behavior defined: detection, degradation, recovery
