Code Visualizer Skill Purpose
Automatically generate and maintain visual code flow diagrams. This skill analyzes Python module structure, detects import relationships, and generates mermaid diagrams. It also monitors for staleness when code changes but diagrams don't.
Philosophy Alignment
This skill embodies amplihack's core philosophy:
Ruthless Simplicity Single responsibility: Visualize code structure - nothing more Minimal dependencies: Uses only Python AST for analysis, delegates diagram syntax to mermaid-diagram-generator No over-engineering: Timestamp-based staleness is simple and "good enough" for 90% of cases Zero-BS Implementation Real analysis: Actually parses Python AST to extract imports - no mock data Honest limitations: Staleness detection is timestamp-based, not semantic (see Limitations section) Working code: All algorithms shown are functional, not pseudocode Modular Design (Bricks & Studs) This skill is one brick: Code analysis and staleness detection Delegates to other bricks: mermaid-diagram-generator for syntax, visualization-architect for complex diagrams Clear studs (public contract): Analyze modules, generate diagrams, check freshness Skill Delegation Architecture code-visualizer (this skill) ├── Responsibilities: │ ├── Python module analysis (AST parsing) │ ├── Import relationship extraction │ ├── Staleness detection (timestamp-based) │ └── Orchestration of diagram generation │ └── Delegates to: ├── mermaid-diagram-generator skill │ ├── Mermaid syntax generation │ ├── Diagram formatting and styling │ └── Markdown embedding │ └── visualization-architect agent ├── Complex multi-level architecture ├── ASCII art alternatives └── Cross-module dependency graphs
Invocation Pattern:
code-visualizer analyzes code structure
modules = analyze_python_modules("src/") relationships = extract_import_relationships(modules)
Then delegates to mermaid-diagram-generator for syntax
Skill(skill="mermaid-diagram-generator")
Provide: Module relationships, diagram type (flowchart/class), styling preferences
Receive: Valid mermaid syntax ready for embedding
For complex architectures, delegates to visualization-architect
Task(subagent_type="visualization-architect", prompt="Create multi-level diagram for...")
When to Use This Skill New Module Creation: Auto-generate architecture diagram for new modules PR Reviews: Show architecture impact of proposed changes Staleness Detection: Check if existing diagrams reflect current code Dependency Analysis: Visualize import relationships Refactoring: Understand module dependencies before changes Quick Start Generate Diagram for Module User: Generate a code flow diagram for the authentication module
Check Diagram Freshness User: Are my architecture diagrams up to date?
Show PR Impact User: What architecture changes does this PR introduce?
Core Capabilities 1. Module Analysis
Analyzes Python files to extract:
Import statements (internal and external) Class definitions and inheritance Function exports (all) Module dependencies 2. Diagram Generation
Creates mermaid diagrams showing:
Module relationships (flowchart) Class hierarchies (class diagram) Data flow between components Dependency graphs 3. Staleness Detection
Compares:
File modification timestamps Git history for changes Diagram content vs actual code structure Missing modules in diagrams Analysis Process Step 1: Discover Modules
Scan target directory for Python modules
modules = glob("*/.py") packages = identify_packages(modules)
Step 2: Extract Relationships
For each module:
Parse import statements Identify local vs external imports Build dependency graph Detect circular dependencies Step 3: Generate Diagram flowchart TD subgraph core["Core Modules"] auth[auth.py] users[users.py] api[api.py] end
subgraph utils["Utilities"]
helpers[helpers.py]
validators[validators.py]
end
api --> auth
api --> users
auth --> helpers
users --> validators
Step 4: Check Freshness
Compare diagram timestamps with source files:
Diagram older than sources = STALE Missing modules in diagram = INCOMPLETE Extra modules in diagram = OUTDATED Diagram Types Module Dependency Graph
Best for: Showing import relationships between files
flowchart LR main[main.py] --> auth[auth/] main --> api[api/] auth --> models[models.py] api --> auth
Class Hierarchy
Best for: Showing inheritance and composition
classDiagram class BaseService { +process() } class AuthService { +login() +logout() } BaseService <|-- AuthService
Data Flow
Best for: Showing how data moves through system
flowchart TD Request[HTTP Request] --> Validate{Validate} Validate -->|Valid| Process[Process] Validate -->|Invalid| Error[Return Error] Process --> Response[HTTP Response]
Staleness Detection How It Works Find Diagrams: Locate mermaid diagrams in README.md, ARCHITECTURE.md Extract Modules: Parse diagram for referenced modules Compare: Check if all current modules are represented Report: Generate freshness report Freshness Report Format
Diagram Freshness Report
Status: STALE
Diagrams Checked: 3 Fresh: 1 Stale: 2
Details
| File | Last Updated | Code Changed | Status |
| ------------ | ------------ | ------------ | ------ |
| README.md | 2025-01-01 | 2025-01-15 | STALE |
| docs/ARCH.md | 2025-01-10 | 2025-01-10 | FRESH |
Missing from Diagrams
new_module.py(added 2025-01-12)api/v2.py(added 2025-01-14)
Recommended Actions
- Update README.md architecture diagram
- Add new_module.py to dependency graph
PR Architecture Impact What It Shows
For a given PR or set of changes:
New modules/files added Changed import relationships Deleted dependencies Modified class hierarchies Impact Diagram flowchart TD subgraph added["New"] style added fill:#90EE90 new_api[api/v2.py] end
subgraph modified["Modified"]
style modified fill:#FFE4B5
auth[auth.py]
end
subgraph existing["Unchanged"]
users[users.py]
models[models.py]
end
new_api --> auth
auth --> models
users --> models
Integration with Other Skills Mermaid Diagram Generator
This skill uses mermaid-diagram-generator for:
Syntax generation Diagram formatting Embedding in markdown Visualization Architect Agent
Delegates to visualization-architect for:
Complex architecture visualization ASCII art alternatives Multi-level diagrams Usage Examples Example 1: New Module Diagram User: I just created a new payment module. Generate an architecture diagram.
Claude: 1. Analyzes payment/ directory 2. Extracts imports and dependencies 3. Generates mermaid flowchart 4. Suggests where to embed (README.md)
Example 2: Check Staleness User: Are my diagrams up to date?
Claude: 1. Finds all mermaid diagrams in docs 2. Compares with current codebase 3. Reports stale diagrams 4. Lists missing modules 5. Suggests updates
Example 3: PR Impact User: Show architecture impact of this PR
Claude: 1. Gets changed files from PR 2. Identifies new/modified/deleted modules 3. Generates impact diagram 4. Highlights dependency changes
Detection Algorithms Import Analysis
Extract imports from Python file
import ast
def extract_imports(file_path): """Extract import statements from Python file.""" tree = ast.parse(Path(file_path).read_text()) imports = [] for node in ast.walk(tree): if isinstance(node, ast.Import): for alias in node.names: imports.append(alias.name) elif isinstance(node, ast.ImportFrom): if node.module: imports.append(node.module) return imports
Staleness Check def check_staleness(diagram_file, source_dir): """Check if diagram is stale compared to source.""" diagram_mtime = Path(diagram_file).stat().st_mtime
for source in Path(source_dir).rglob("*.py"):
if source.stat().st_mtime > diagram_mtime:
return True, source # Stale
return False, None # Fresh
Best Practices When to Update Diagrams New modules: Add to dependency graph Changed imports: Update relationships Deleted files: Remove from diagrams Architectural changes: Regenerate completely Diagram Placement Diagram Type Recommended Location Module overview README.md Detailed architecture docs/ARCHITECTURE.md Package structure package/README.md API flow api/README.md Naming Conventions
Architecture
flowchart TD
...
Success Criteria
A good visualization:
Shows all current modules Reflects actual import relationships Uses appropriate diagram type Placed in discoverable location Includes freshness metadata Clear and not overcrowded Limitations
IMPORTANT: Understand these limitations before relying on this skill:
Staleness Detection Limitations
Timestamp-based, not semantic: Detection compares file modification times, not actual code changes
A file touched but not meaningfully changed will trigger "stale" Reformatting code triggers false positives Git operations that update mtime trigger false positives
Cannot detect logic changes: Adding a function that doesn't change imports won't be detected
Internal refactoring within a module is invisible Changes to function signatures not reflected New class methods added without import changes won't show
Import-centric view: Only tracks import relationships
Runtime dependencies (dependency injection) not detected Configuration-based connections invisible Duck typing relationships not captured Scope Limitations
Python-only: Currently only analyzes Python files
No TypeScript, JavaScript, Rust, Go support Multi-language projects partially covered
Static analysis only: No runtime information
Dynamic imports (import, importlib) not detected Conditional imports may be missed Plugin architectures not fully represented
Single-project scope: Cannot analyze cross-repository dependencies
External package internals not shown Monorepo relationships require manual configuration Accuracy Expectations Scenario Accuracy Notes New module detection 95%+ Reliable for Python modules Import relationship mapping 90%+ Misses dynamic imports Staleness detection 70-80% False positives common Circular dependency detection 85%+ May miss complex cycles Class hierarchy extraction 85%+ Mixins can be tricky When NOT to Use This Skill Security-critical dependency audits: Use proper security scanning tools Runtime dependency analysis: Use profilers or dynamic analysis tools Cross-language projects: Manual analysis may be more accurate Heavily dynamic codebases: Plugin architectures, metaprogramming Dependencies
This skill requires:
mermaid-diagram-generator skill: Must be available for diagram syntax generation Python 3.8+: For AST parsing features used Git (optional): For enhanced staleness detection using git history
If mermaid-diagram-generator is unavailable, this skill will provide raw relationship data but cannot generate embedded diagrams.
PR Review Integration How Diagrams Appear in PRs
When reviewing PRs, this skill generates impact diagrams that can be added to PR descriptions:
PR Description Template:
Architecture Impact
Changed Dependencies
flowchart LR
subgraph changed["Modified Modules"]
style changed fill:#FFE4B5
auth[auth/service.py]
api[api/routes.py]
end
subgraph added["New Modules"]
style added fill:#90EE90
oauth[auth/oauth.py]
end
subgraph unchanged["Existing"]
models[models/user.py]
db[db/connection.py]
end
oauth --> auth
auth --> models
api --> auth
api --> db
Impact Summary
- New modules: 1 (oauth.py)
- Modified modules: 2 (auth/service.py, api/routes.py)
- New dependencies: oauth.py -> auth/service.py
- Diagrams to update: README.md (STALE)
CI Integration Example
Add to .github/workflows/pr-review.yml:
- name: Check Diagram Staleness run: | # Claude Code analyzes and reports # Outputs: STALE diagrams that need updating # Generates: Suggested diagram updates
Reviewer Workflow PR opened -> code-visualizer generates impact diagram Reviewer sees -> Visual diff of architecture changes Staleness check -> Warns if existing diagrams need updates Action items -> Lists diagrams requiring manual update Remember
This skill automates what developers often forget:
Keeping diagrams in sync with code Documenting architecture changes Understanding dependency impacts
The goal is diagrams that stay fresh automatically.
But remember the limitations: Staleness detection is approximate. When accuracy matters, verify manually.