Agent skill
data-substrate-analysis
Analyze fundamental data primitives, type systems, and state management patterns in a codebase. Use when (1) evaluating typing strategies (Pydantic vs TypedDict vs loose dicts), (2) assessing immutability and mutation patterns, (3) understanding serialization approaches, (4) documenting state shape and lifecycle, or (5) comparing data modeling approaches across frameworks.
Install this agent skill to your Project
npx add-skill https://github.com/aiskillstore/marketplace/tree/main/skills/dowwie/data-substrate-analysis
SKILL.md
Data Substrate Analysis
Analyzes the fundamental units of data and state management patterns.
Process
- Locate type files — Find types.py, schema.py, models.py, state.py
- Classify typing — Strict (Pydantic), structural (TypedDict), loose (dict)
- Analyze mutation — In-place modification vs. copy-on-write
- Document serialization — json(), dict(), pickle, custom methods
Typing Strategy Classification
Detection Patterns
| Strategy | Indicators | Files to Check |
|---|---|---|
| Pydantic | BaseModel, Field(), validator |
models.py, schema.py |
| Dataclass | @dataclass, field() |
types.py, models.py |
| TypedDict | TypedDict, Required[], NotRequired[] |
types.py |
| NamedTuple | NamedTuple, typing.NamedTuple |
types.py |
| Loose | Dict[str, Any], plain dict |
Throughout |
Analysis Questions
- Are boundaries validated (API ingress/egress)?
- Is nesting depth reasonable (<3 levels)?
- Are optional fields explicit or implicit None?
- Version migration path (Pydantic V1 → V2)?
Immutability Analysis
Mutable Patterns (Risk Indicators)
# In-place list modification
state.messages.append(msg)
state.history.extend(new_items)
# Direct dict mutation
state['key'] = value
state.update(new_data)
# Object attribute mutation
state.status = 'complete'
Immutable Patterns (Safer)
# Pydantic copy
new_state = state.model_copy(update={'key': value})
# Dataclass replace
new_state = replace(state, messages=[*state.messages, msg])
# Spread operator style
new_state = {**state, 'key': value}
# Frozen dataclass
@dataclass(frozen=True)
class State: ...
Serialization Strategy
Common Patterns
| Method | Code Pattern | Trade-offs |
|---|---|---|
| Pydantic JSON | .model_dump_json() |
Type-safe, automatic |
| Pydantic Dict | .model_dump() |
For internal use |
| Dataclass | asdict(obj) |
Manual, no validation |
| Custom | to_dict(), from_dict() |
Full control |
| Pickle | pickle.dumps() |
Fast, fragile, security risk |
| JSON | json.dumps(obj, default=...) |
Requires encoder |
Questions to Answer
- Is serialization implicit (automatic) or explicit (manual)?
- How are nested objects handled?
- Is deserialization validated?
- What happens with unknown fields?
Output Template
## Data Substrate Analysis: [Framework Name]
### Typing Strategy
- **Primary Approach**: [Pydantic/Dataclass/TypedDict/Loose]
- **Key Files**: [List of files]
- **Nesting Depth**: [Shallow/Medium/Deep]
- **Validation**: [At boundaries/Everywhere/None]
### Core Primitives
| Type | Location | Purpose | Mutability |
|------|----------|---------|------------|
| Message | schema.py:L15 | Chat message | Immutable |
| State | state.py:L42 | Agent state | Mutable ⚠️ |
| Result | types.py:L78 | Tool output | Immutable |
### Mutation Analysis
- **Pattern**: [In-place/Copy-on-write/Mixed]
- **Risk Areas**: [List of mutable state locations]
- **Concurrency Safe**: [Yes/No/Partial]
### Serialization
- **Method**: [Pydantic/Custom/JSON]
- **Implicit/Explicit**: [Description]
- **Round-trip Tested**: [Yes/No/Unknown]
Integration
- Prerequisite:
codebase-mappingto identify type files - Feeds into:
comparative-matrixfor typing decisions - Related:
resilience-analysisfor error handling in serialization
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
perigon-backend
Perigon ASP.NET Core + EF Core + Aspire conventions
perigon-agent
Pointers for Copilot/agents to apply Perigon conventions
perigon-angular
Angular 21+ standalone/Material/signal conventions for Perigon WebApp
fastapi-mastery
Comprehensive FastAPI development skill covering REST API creation, routing, request/response handling, validation, authentication, database integration, middleware, and deployment. Use when working with FastAPI projects, building APIs, implementing CRUD operations, setting up authentication/authorization, integrating databases (SQL/NoSQL), adding middleware, handling WebSockets, or deploying FastAPI applications. Triggered by requests involving .py files with FastAPI code, API endpoint creation, Pydantic models, or FastAPI-specific features.
context7-efficient
Token-efficient library documentation fetcher using Context7 MCP with 86.8% token savings through intelligent shell pipeline filtering. Fetches code examples, API references, and best practices for JavaScript, Python, Go, Rust, and other libraries. Use when users ask about library documentation, need code examples, want API usage patterns, are learning a new framework, need syntax reference, or troubleshooting with library-specific information. Triggers include questions like "Show me React hooks", "How do I use Prisma", "What's the Next.js routing syntax", or any request for library/framework documentation.
browser-use
Browser automation using Playwright MCP. Navigate websites, fill forms, click elements, take screenshots, and extract data. Use when tasks require web browsing, form submission, web scraping, UI testing, or any browser interaction.
Didn't find tool you were looking for?