---
name: serena-code-architecture
description: Architectural analysis workflow using Serena symbols and Forgetful memory. Use when you say "analyze the architecture of this project", "map out the codebase structure", "trace dependencies for this component", "document the architecture", or "what components does this project have". Do NOT use to populate the knowledge base from scratch (use encode-repo-serena) or for symbol-edit guidance (use using-serena-symbols).
license: MIT
metadata:
version: 1.0.0
model: claude-opus-4-6
---

# Architectural Analysis with Serena + Forgetful

This skill guides systematic architectural analysis using Serena's symbol-level understanding, with optional persistence to Forgetful's knowledge graph.

## Triggers

| Trigger Phrase | Operation |
|----------------|-----------|
| `analyze the architecture of this project` | Full 6-phase analysis workflow |
| `map out the codebase structure` | Phase 1-3 discovery and component mapping |
| `trace dependencies for this component` | Phase 4 dependency tracing |
| `create architecture memories` | Phase 5-6 memory and entity creation |
| `what components does this project have` | Phase 3 core component mapping |

---

## When to Use This Skill

Use this skill when:

- Analyzing a new codebase before implementing changes
- Documenting existing architecture for a project
- Creating component entities and relationships in Forgetful
- Understanding dependencies and call hierarchies
- Building a knowledge graph from code structure

Use [using-serena-symbols](../using-serena-symbols/SKILL.md) instead when:

- Quick symbol lookup without memory persistence
- Finding a specific class or method definition
- Tracing references for a single symbol

## Analysis Workflow

### Phase 1: Project Structure Discovery

Understand the high-level layout:

```python
# Get directory structure
mcp__plugin_serena_serena__list_dir({
  "relative_path": ".",
  "recursive": false
})

# Identify key directories (src/, app/, lib/, etc.)
mcp__plugin_serena_serena__list_dir({
  "relative_path": "src",
  "recursive": true
})
```

**Goal**: Identify entry points, main modules, and organizational patterns.

### Phase 2: Entry Point Analysis

Find the application entry points:

```python
# Look for main/app files
mcp__plugin_serena_serena__search_for_pattern({
  "substring_pattern": "if __name__.*==.*__main__|def main\\(|app\\s*=\\s*FastAPI|createApp",
  "restrict_search_to_code_files": true
})

# Get symbols from entry file
mcp__plugin_serena_serena__get_symbols_overview({
  "relative_path": "src/main.py",
  "depth": 1
})
```

### Phase 3: Core Component Mapping

Identify and analyze major components:

```python
# Find all service/controller/model classes
mcp__plugin_serena_serena__find_symbol({
  "name_path_pattern": "Service",
  "substring_matching": true,
  "include_kinds": [5],  # Class only
  "depth": 1
})

# For each major component, get full structure
mcp__plugin_serena_serena__find_symbol({
  "name_path_pattern": "AuthService",
  "include_body": false,
  "depth": 1  # Get methods
})
```

### Phase 4: Dependency Tracing

Understand how components connect:

```python
# Find who uses AuthService
mcp__plugin_serena_serena__find_referencing_symbols({
  "name_path": "AuthService",
  "relative_path": "src/services/auth.py"
})

# Find what AuthService depends on
mcp__plugin_serena_serena__find_symbol({
  "name_path_pattern": "AuthService/__init__",
  "include_body": true
})
```

### Phase 5: Create Architectural Memories (Optional)

Store findings in Forgetful:

```python
# First, find/create the project
execute_forgetful_tool("list_projects", {"repo_name": "owner/repo"})

# Create memory for architectural insight
execute_forgetful_tool("create_memory", {
  "title": "AuthService: Core authentication component",
  "content": "AuthService handles JWT validation, user sessions, and OAuth flows. Dependencies: UserRepository, TokenService, CacheService. Used by: all API endpoints via middleware.",
  "context": "Discovered during architectural analysis",
  "keywords": ["auth", "jwt", "service", "architecture"],
  "tags": ["architecture", "component"],
  "importance": 8,
  "project_ids": [PROJECT_ID]
})
```

### Phase 6: Entity Graph Creation (Optional)

Create entities for major components:

```python
# Check if entity exists first
execute_forgetful_tool("search_entities", {"query": "AuthService"})

# Create component entity
execute_forgetful_tool("create_entity", {
  "name": "AuthService",
  "entity_type": "other",
  "custom_type": "Service",
  "notes": "Core authentication service - JWT, OAuth, sessions",
  "tags": ["service", "auth"],
  "project_ids": [PROJECT_ID]
})

# Create relationships
execute_forgetful_tool("create_entity_relationship", {
  "source_entity_id": AUTH_SERVICE_ID,
  "target_entity_id": USER_REPO_ID,
  "relationship_type": "depends_on",
  "strength": 0.9
})

# Link entity to memories
execute_forgetful_tool("link_entity_to_memory", {
  "entity_id": AUTH_SERVICE_ID,
  "memory_id": ARCH_MEMORY_ID
})
```

## Relationship Types

Standard relationship types for architecture:

| Type | Use For |
|------|---------|
| `uses` | General usage (A uses B) |
| `depends_on` | Dependency (A requires B) |
| `calls` | Direct function/method calls |
| `extends` | Class inheritance |
| `implements` | Interface implementation |
| `connects_to` | External connections (DB, API) |
| `contains` | Composition (A contains B) |

## Entity Types for Architecture

| Type | Use For |
|------|---------|
| `Service` | Business logic services |
| `Repository` | Data access layer |
| `Controller` | Request handlers |
| `Middleware` | Request/response processing |
| `Model` | Data models/entities |
| `Library` | External dependencies |
| `Framework` | Framework components |

## Example: FastAPI Project Analysis

```python
# 1. Find routers
mcp__plugin_serena_serena__search_for_pattern({
  "substring_pattern": "APIRouter\\(\\)|router\\s*=",
  "restrict_search_to_code_files": true
})

# 2. Analyze router structure
mcp__plugin_serena_serena__get_symbols_overview({
  "relative_path": "src/routers/users.py",
  "depth": 1
})

# 3. Find dependency injection
mcp__plugin_serena_serena__search_for_pattern({
  "substring_pattern": "Depends\\(",
  "restrict_search_to_code_files": true,
  "context_lines_before": 1,
  "context_lines_after": 1
})

# 4. Trace service dependencies
mcp__plugin_serena_serena__find_referencing_symbols({
  "name_path": "get_current_user",
  "relative_path": "src/dependencies/auth.py"
})

# 5. Create architecture memory
execute_forgetful_tool("create_memory", {
  "title": "FastAPI app structure: Routers + Dependencies",
  "content": "App uses router-based organization with dependency injection. Routers: /users, /auth, /products. Dependencies: get_current_user, get_db. All routes require auth except /auth/login.",
  "context": "FastAPI architecture analysis",
  "keywords": ["fastapi", "router", "dependency-injection"],
  "tags": ["architecture", "pattern"],
  "importance": 8,
  "project_ids": [PROJECT_ID]
})
```

## Analysis Checklist

- [ ] Directory structure mapped
- [ ] Entry points identified
- [ ] Major components catalogued
- [ ] Dependencies traced
- [ ] External connections documented
- [ ] Key patterns identified
- [ ] Memories created for insights
- [ ] Entities created for components (if applicable)
- [ ] Relationships mapped (if applicable)

## Anti-Patterns

| Avoid | Why | Instead |
|-------|-----|---------|
| Analyzing every class as a component | Creates noise in entity graph | Focus on major architectural components only |
| Reading full source before overview | Wastes tokens on unneeded code | Start with get_symbols_overview, read selectively |
| Creating entities without memories | Entities lack context without linked knowledge | Create memory first, then entity, then link them |
| Skipping dependency tracing | Misses critical coupling relationships | Always run Phase 4 for components you create entities for |
| Documenting WHAT without WHY | Memories become stale quickly | Focus memories on rationale and trade-offs |

---

## Verification

After architectural analysis:

- [ ] Directory structure mapped (Phase 1)
- [ ] Entry points identified (Phase 2)
- [ ] Major components catalogued (Phase 3)
- [ ] Dependencies traced for key components (Phase 4)
- [ ] Memories created with importance 7+ for insights
- [ ] Entities linked to corresponding memories

---

## Tips

1. **Work incrementally** - Don't try to analyze everything at once
2. **Focus on interfaces** - Public methods/APIs matter more than internals
3. **Document decisions** - Create memories for WHY, not just WHAT
4. **Use entities sparingly** - Only major components, not every class
5. **Link across projects** - Architecture patterns often apply elsewhere