# Arch Lens Data Lineage

> Create Data Lineage architecture diagram showing information flow, transformations, and storage destinations. Data-centric lens answering "Where is the data?

- **Type:** Skill
- **Install:** `agentstack add skill-talont-org-autoskillit-arch-lens-data-lineage`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [TalonT-Org](https://agentstack.voostack.com/s/talont-org)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [TalonT-Org](https://github.com/TalonT-Org)
- **Source:** https://github.com/TalonT-Org/AutoSkillit/tree/main/src/autoskillit/skills_extended/arch-lens-data-lineage

## Install

```sh
agentstack add skill-talont-org-autoskillit-arch-lens-data-lineage
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Data Lineage Architecture Lens

**Cognitive Mode:** Data-Centric
**Primary Question:** "Where is the data?"
**Focus:** Information Flow, Transformations, Storage Locations, Format Conversions

## When to Use

- Need to understand how data flows through the system
- Documenting data transformations and conversions
- Identifying storage destinations and access patterns
- User invokes `/autoskillit:arch-lens-data-lineage` or `/autoskillit:make-arch-diag data`

## Critical Constraints

**NEVER:**
- Modify any source code files
- Focus on runtime behavior (that's process flow lens)
- Show static structure without data context
- Run subagents in the background (`run_in_background: true` is prohibited)

**ALWAYS:**
- Trace data from INPUT to STORAGE
- Show transformation stages and format changes
- Identify the single source of truth
- Distinguish read vs write operations
- BEFORE creating any diagram, LOAD the `/autoskillit:mermaid` skill using the Skill tool - this is MANDATORY
- If the Skill tool cannot be used (disable-model-invocation) or refuses this invocation, do NOT proceed with diagram creation. Abort this step and omit the diagram from output.
- After writing the diagram file, emit the **absolute path** as a structured output
  token as your final output. Resolve the relative `temp/arch-lens-data-lineage/...`
  save path to absolute by prepending the full CWD:
  ```
  diagram_path = /absolute/cwd/temp/arch-lens-data-lineage/{filename}.md
  ```
  This token is MANDATORY — the pipeline cannot proceed without it.

## Arguments

`/autoskillit:arch-lens-data-lineage [context_path]`

- **context_path** (optional) — Absolute path to a PR context file containing new files
  (★-prefixed) and modified files (●-prefixed) from the PR diff. When provided, read
  this file before beginning analysis and focus the diagram on the architectural areas
  affected by these specific files. When absent, explore the full CWD.

---

## Analysis Workflow

### Step 0: Read PR context (when provided)

If a `context_path` positional argument is present:
1. Read the file at `context_path`
2. Extract: new files list (★-prefixed), modified files list (●-prefixed)
3. Focus Step 1 exploration on the modules/components these files belong to
4. Apply ★ prefix on diagram nodes representing new files/components
5. Apply ● prefix on diagram nodes representing modified files/components

If no `context_path` is provided, skip this step and explore the full CWD in Step 1.

### Step 1: Launch Parallel Exploration Subagents

Spawn Explore subagents to investigate:

**Data Origins (Inputs)**
- Find user input handling
- Identify external data sources
- Look for: CLI args, API requests, file reads, imports, user input, data ingestion

**Transformation Stages**
- Find data conversion/transformation code
- Identify adapters and converters
- Look for: Adapter, Converter, transform, parse, serialize, from_*, to_*, mapping, conversion

**Format Changes**
- Find schema definitions and conversions
- Identify format boundaries (JSON, XML, protobuf, etc.)
- Look for: schema models, type definitions, serialization, deserialization, format conversion

**Storage Destinations**
- Find database operations
- Identify file outputs
- Look for: database operations, persistence, .save(), .create(), .write(), storage

**Access Patterns**
- Find data retrieval code
- Identify query patterns
- Look for: .get(), .query(), .find(), .load(), read operations, data access layer

### Step 2: Map Data Flow

Document the journey of key data entities:
- **Origin**: Where does it come from?
- **Transformations**: What changes happen?
- **Storage**: Where is it persisted?
- **Retrieval**: How is it accessed later?

**CRITICAL - Analyze Read/Write Direction:**
For EVERY storage location and data flow:
- **Read sources (inputs)**: Components that READ from this location
- **Write destinations (outputs)**: Components that WRITE to this location
- **Read-write (primary storage)**: Both read and written by the system
- **Write-only (artifacts)**: Written but NEVER read back by the system

Clearly distinguish:
- Primary storage (source of truth) - system reads AND writes
- Write-only artifacts (debugging, logging) - system writes but never reads back
- External inputs - system reads only

Use different arrow styles:
- Solid arrows for read/write primary storage
- Dashed arrows for write-only artifacts

### Step 3: Identify Conversion Boundaries

Find format changes:
- External format -> Internal format
- Internal format -> Database format
- Database format -> API response
- Note naming convention changes

### Step 4: Create the Diagram

Use flowchart with:

**Direction:** `LR` (left-to-right) for data flow, or `TB` for hierarchical

**Subgraphs for Stages:**
- Input/Origins
- Transformation/Processing
- Storage (primary)
- Artifacts (secondary/write-only)
- External Sync (if applicable)

**Node Styling:**
- `cli` class: Data origins, user input
- `handler` class: Transformation, adapters
- `stateNode` class: Database tables, primary storage
- `output` class: Write-only artifacts, files
- `integration` class: External sync, APIs

**Connection Types:**
- Solid arrows for primary data flow
- Dashed arrows for write-only/secondary
- Label with operation names

**Database Nodes:**
- Use cylinder shape: `[(Label)]`
- Show table relationships

### Step 5: Write Output

Write the diagram to: `{{AUTOSKILLIT_TEMP}}/arch-lens-data-lineage/arch_diag_data_lineage_{YYYY-MM-DD_HHMMSS}.md` (relative to the current working directory)

After writing the diagram file, emit a structured output line:

> **IMPORTANT:** Emit the structured output tokens as **literal plain text with no
> markdown formatting on the token names**. Do not wrap token names in `**bold**`,
> `*italic*`, or any other markdown. The adjudicator performs a regex match on the
> exact token name — decorators cause match failure.

```
diagram_path = {absolute_path_to_diagram_file}
```

---

## Output Template

```markdown
# Data Lineage Diagram: {System Name}

**Lens:** Data Lineage (Data-Centric)
**Question:** Where is the data?
**Date:** {YYYY-MM-DD}
**Scope:** {What was analyzed}

## Data Flow Overview

| Stage | Format | Key Transformation |
|-------|--------|-------------------|
| Input | {format} | {description} |
| Processing | {format} | {description} |
| Storage | {format} | {description} |

## Lineage Diagram

```mermaid
%%{init: {'flowchart': {'nodeSpacing': 50, 'rankSpacing': 60, 'curve': 'basis'}}}%%
flowchart LR
    %% CLASS DEFINITIONS %%
    classDef cli fill:#1a237e,stroke:#7986cb,stroke-width:2px,color:#fff;
    classDef stateNode fill:#004d40,stroke:#4db6ac,stroke-width:2px,color:#fff;
    classDef handler fill:#e65100,stroke:#ffb74d,stroke-width:2px,color:#fff;
    classDef phase fill:#6a1b9a,stroke:#ba68c8,stroke-width:2px,color:#fff;
    classDef output fill:#00695c,stroke:#4db6ac,stroke-width:2px,color:#fff;
    classDef integration fill:#c62828,stroke:#ef9a9a,stroke-width:2px,color:#fff;

    subgraph Input ["Data Origins"]
        USER["User Input━━━━━━━━━━Source typeFormat"]
    end

    subgraph Transform ["Transformation"]
        direction TB
        ADAPTER["Adapter━━━━━━━━━━Conversion type"]
    end

    subgraph Storage ["Primary Storage (Source of Truth)"]
        direction TB
        DB[("Database Table━━━━━━━━━━Key fields")]
    end

    subgraph Artifacts ["Write-Only Artifacts"]
        direction TB
        FILE["output.json━━━━━━━━━━For debugging"]
    end

    %% FLOWS %%
    USER -->|"input"| ADAPTER
    ADAPTER -->|"save()"| DB
    DB -.->|"write-only"| FILE

    %% CLASS ASSIGNMENTS %%
    class USER cli;
    class ADAPTER handler;
    class DB stateNode;
    class FILE output;
```

**Color Legend:**
| Color | Category | Description |
|-------|----------|-------------|
| Dark Blue | Input | Data origins (user, external) |
| Orange | Transform | Format conversion and adapters |
| Teal | Storage | Primary storage (source of truth) |
| Dark Teal | Artifacts | Write-only outputs |
| Red | Sync | External sync services |

## Data Transformation Summary

| Stage | Format | Key Conversion |
|-------|--------|----------------|
| {stage} | {format} | {conversion} |

## Storage Destinations

| Entity | Primary Storage | Secondary | Access Pattern |
|--------|-----------------|-----------|----------------|
| {entity} | {location} | {artifact} | {how accessed} |

## Critical Design Principle

> **Source of Truth**: {e.g., "Database is single source of truth. File outputs are write-only."}
```

---

## Pre-Diagram Checklist

Before creating the diagram, verify:

- [ ] LOADED `/autoskillit:mermaid` skill using the Skill tool
- [ ] Using ONLY classDef styles from the mermaid skill (no invented colors)
- [ ] Diagram will include a color legend table

---

## Related Skills

- `/autoskillit:make-arch-diag` - Parent skill for lens selection
- `/autoskillit:mermaid` - MUST BE LOADED before creating diagram
- `/autoskillit:arch-lens-c4-container` - For container-level storage view

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [TalonT-Org](https://github.com/TalonT-Org)
- **Source:** [TalonT-Org/AutoSkillit](https://github.com/TalonT-Org/AutoSkillit)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-talont-org-autoskillit-arch-lens-data-lineage
- Seller: https://agentstack.voostack.com/s/talont-org
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.