# Architecture Plan: [TASK-ID] - [Task Title]

## Overview

**Task**: [Brief description of the task]
**Date**: [YYYY-MM-DD]
**Author**: [Agent/Human]

---

## 1. Technology Choices

### Selected Technologies

| Component         | Technology         | Version      | Rationale         |
| ----------------- | ------------------ | ------------ | ----------------- |
| [e.g., Runtime]   | [e.g., Node.js]    | [e.g., 20.x] | [Why this choice] |
| [e.g., Database]  | [e.g., PostgreSQL] | [e.g., 15]   | [Why this choice] |
| [e.g., Framework] | [e.g., Express]    | [e.g., 4.x]  | [Why this choice] |

### Alternatives Considered

| Alternative    | Pros       | Cons        | Rejection Reason   |
| -------------- | ---------- | ----------- | ------------------ |
| [Technology A] | [Benefits] | [Drawbacks] | [Why not selected] |
| [Technology B] | [Benefits] | [Drawbacks] | [Why not selected] |

---

## 2. Component Boundaries

### Components Overview

```
[High-level diagram or ASCII representation]

e.g.:
+----------------+     +----------------+     +----------------+
|   Frontend     | --> |    API Layer   | --> |   Database     |
|   (React)      |     |   (Express)    |     |  (PostgreSQL)  |
+----------------+     +----------------+     +----------------+
                              |
                              v
                       +----------------+
                       | External APIs  |
                       +----------------+
```

### Component Responsibilities

| Component     | Responsibility | Boundaries            |
| ------------- | -------------- | --------------------- |
| [Component A] | [What it does] | [What it does NOT do] |
| [Component B] | [What it does] | [What it does NOT do] |
| [Component C] | [What it does] | [What it does NOT do] |

### Interface Contracts

| Interface     | From        | To          | Contract Type          |
| ------------- | ----------- | ----------- | ---------------------- |
| [Interface A] | [Component] | [Component] | [REST/gRPC/Event/etc.] |
| [Interface B] | [Component] | [Component] | [REST/gRPC/Event/etc.] |

---

## 3. Integration Points

### Internal Integrations

| Integration               | Type         | Protocol           | Data Format     |
| ------------------------- | ------------ | ------------------ | --------------- |
| [Service A <-> Service B] | [Sync/Async] | [HTTP/gRPC/Events] | [JSON/Protobuf] |

### External Integrations

| External System    | Purpose              | Authentication  | Rate Limits    |
| ------------------ | -------------------- | --------------- | -------------- |
| [e.g., Stripe API] | [Payment processing] | [API Key/OAuth] | [100 req/min]  |
| [e.g., SendGrid]   | [Email delivery]     | [API Key]       | [1000 req/min] |

### Data Flow

```
[Data flow diagram or description]

e.g.:
User Request --> API Gateway --> Auth Middleware --> Route Handler
    --> Service Layer --> Repository --> Database
    --> Response Serialisation --> User Response
```

---

## 4. Key Constraints

### Technical Constraints

| Constraint                            | Impact                               | Mitigation                       |
| ------------------------------------- | ------------------------------------ | -------------------------------- |
| [e.g., Must use existing auth system] | [Limits custom auth]                 | [Extend existing, don't replace] |
| [e.g., Max 200ms response time]       | [No complex queries in request path] | [Use caching, async processing]  |

### Business Constraints

| Constraint                                   | Impact                                 | Mitigation                        |
| -------------------------------------------- | -------------------------------------- | --------------------------------- |
| [e.g., Must maintain backward compatibility] | [Cannot change existing API contracts] | [Version API, deprecation period] |
| [e.g., GDPR compliance required]             | [Data handling restrictions]           | [Implement data anonymisation]    |

### Resource Constraints

| Constraint                    | Impact                        | Mitigation                     |
| ----------------------------- | ----------------------------- | ------------------------------ |
| [e.g., Limited team capacity] | [Cannot parallelise work]     | [Sequential implementation]    |
| [e.g., Budget limits]         | [Cannot use premium services] | [Use open-source alternatives] |

---

## 5. Trade-offs

### Key Trade-off Decisions

| Decision             | Option A                | Option B                   | Chosen | Rationale                           |
| -------------------- | ----------------------- | -------------------------- | ------ | ----------------------------------- |
| [e.g., Data storage] | [SQL - ACID guarantees] | [NoSQL - horizontal scale] | [SQL]  | [Data consistency critical]         |
| [e.g., API style]    | [REST - simplicity]     | [GraphQL - flexibility]    | [REST] | [Team familiarity, simpler caching] |

### Implications of Choices

**Chosen approach enables:**

- [Benefit 1]
- [Benefit 2]

**Chosen approach limits:**

- [Limitation 1]
- [Limitation 2]

---

## 6. Go/No-Go Criteria

### Prerequisites (Must be true to proceed)

| #   | Criterion                             | Status        | Evidence         |
| --- | ------------------------------------- | ------------- | ---------------- |
| 1   | [Required dependency available]       | [ ] Y / [ ] N | [Link/reference] |
| 2   | [Required access/permissions granted] | [ ] Y / [ ] N | [Link/reference] |
| 3   | [Required infrastructure in place]    | [ ] Y / [ ] N | [Link/reference] |
| 4   | [No blocking technical issues]        | [ ] Y / [ ] N | [Link/reference] |

### Validation Checks

| #   | Check                                      | Status        | Notes |
| --- | ------------------------------------------ | ------------- | ----- |
| 1   | Architecture aligns with existing patterns | [ ] Y / [ ] N |       |
| 2   | No security concerns identified            | [ ] Y / [ ] N |       |
| 3   | Performance requirements achievable        | [ ] Y / [ ] N |       |
| 4   | Team has required expertise                | [ ] Y / [ ] N |       |

### Go/No-Go Decision

- [ ] **GO** - Proceed to detailed implementation planning
- [ ] **NO-GO** - Address blocking issues first

**Blocking issues (if No-Go):**

1. [Issue description and resolution path]

---

## 7. Open Questions

| #   | Question                           | Impact            | Owner    | Due Date |
| --- | ---------------------------------- | ----------------- | -------- | -------- |
| 1   | [Question requiring clarification] | [High/Medium/Low] | [Person] | [Date]   |
| 2   | [Question requiring clarification] | [High/Medium/Low] | [Person] | [Date]   |

---

## Approval

| Role          | Name | Status                      | Date |
| ------------- | ---- | --------------------------- | ---- |
| Tech Lead     |      | [ ] Approved / [ ] Rejected |      |
| Architect     |      | [ ] Approved / [ ] Rejected |      |
| Product Owner |      | [ ] Approved / [ ] Rejected |      |

**Next Step**: If approved, proceed to `/plan-implementation` for detailed breakdown.