Process Flow Architecture Lens

Cognitive Mode: Physiological Primary Question: "How does it behave?" Focus: Runtime Behavior, State Transitions, Decision Points, Control Flow

When to Use

• Need to understand runtime execution paths
• Documenting state machines or workflows
• Analyzing decision points and branching logic
• User invokes /arch-lens-process-flow or /make-arch-diag process

Critical Constraints

NEVER:

• Modify any source code files
• Include static structure details (that's C4 lens)
• Show data storage details (that's data lineage lens)

ALWAYS:

• Focus on BEHAVIOR and STATE TRANSITIONS
• Show decision points as diamonds
• Include loop mechanisms and retry logic
• BEFORE creating any diagram, LOAD the /mermaid skill using the Skill tool - this is MANDATORY

Analysis Workflow

Step 1: Launch Parallel Exploration Subagents

Spawn Explore subagents to investigate:

State Machines & Workflows

• Find state definitions and transitions
• Identify workflow orchestration
• Look for: state machine patterns, workflow graphs, FSM implementations, state enum/constants

Entry Points & Triggers

• Find how processes are started
• Identify triggers and events
• Look for: main(), run(), execute(), start(), call, async handlers

Decision Points

• Find conditional logic that affects flow
• Identify routing functions
• Look for: if/else chains, switch/case, route_, should_, can_, is_

Loop Mechanisms

• Find iteration and retry patterns
• Identify continuation conditions
• Look for: while, for, retry logic, max_iterations, loop constructs

Terminal States

• Find completion conditions
• Identify error termination
• Look for: return, raise/throw, complete, error, success, failure states

Step 2: Map State Transitions

For each workflow/state machine discovered:

• States/Nodes: List all distinct states
• Transitions: Map state-to-state connections
• Guards: Conditions that determine transitions
• Actions: What happens during transitions

Step 3: Identify Flow Patterns

Document key patterns:

• Linear sequences (A -> B -> C)
• Branches (decision points)
• Loops (with termination conditions)
• Error paths
• Parallel paths (if any)

CRITICAL - Analyze Read/Write Direction: For EVERY node that interacts with state or storage:

• Reads from: What data does this node consume? From where?
• Writes to: What data does this node produce? To where?
• State mutations: Does it modify in-memory state, database, or files?

Label state interactions on edges:

• "reads" / "loads" / "queries" for input
• "writes" / "saves" / "updates" for output
• Distinguish primary storage (read/write) from write-only artifacts

Step 4: Create the Diagram

Use flowchart with:

Direction: TB for hierarchical flow, LR for sequential processes

Node Types:

• ([Label]) - Rounded: Start/End terminals
• {Label} - Diamond: Decision points
• [Label] - Rectangle: Process nodes
• [[Label]] - Subroutine: Subgraph calls

Subgraphs for Phases:

• Group related states into phases
• Keep START/END outside subgraphs

Node Styling:

• terminal class: START, END, ERROR nodes
• phase class: Control flow, analysis nodes
• handler class: Processing, execution nodes
• stateNode class: Decision, routing nodes
• detector class: Validation gates, failure handling

Edge Labels:

• Show conditions on decision branches
• Include loop counts where relevant

Step 5: Write Output

Write the diagram to: temp/arch-lens-process-flow/arch_diag_process_flow_{YYYY-MM-DD_HHMMSS}.md

Output Template

# Process Flow Diagram: {Workflow Name}

**Lens:** Process Flow (Physiological)
**Question:** How does it behave?
**Date:** {YYYY-MM-DD}
**Scope:** {What was analyzed}

## Workflow Overview

| Phase | Nodes | Key Decision Points | Loop Mechanism |
|-------|-------|---------------------|----------------|
| {phase} | {count} | {decisions} | {loop info} |

## Flow Diagram

```mermaid
%%{init: {'flowchart': {'nodeSpacing': 40, 'rankSpacing': 50, 'curve': 'basis'}}}%%
flowchart TB
    %% CLASS DEFINITIONS %%
    classDef terminal 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 detector fill:#b71c1c,stroke:#ef5350,stroke-width:2px,color:#fff;

    %% TERMINALS %%
    START([START])
    COMPLETE([COMPLETE])
    ERROR([ERROR])

    subgraph Phase1 ["Phase Name"]
        direction TB
        N1["Node Name<br/>━━━━━━━━━━<br/>Description"]
        N2{"Decision<br/>━━━━━━━━━━<br/>Condition?"}
        N3["Process Node<br/>━━━━━━━━━━<br/>Action"]
    end

    %% FLOW %%
    START --> N1
    N1 --> N2
    N2 -->|"condition A"| N3
    N2 -->|"condition B"| ERROR
    N3 --> COMPLETE

    %% CLASS ASSIGNMENTS %%
    class START,COMPLETE,ERROR terminal;
    class N1,N3 handler;
    class N2 stateNode;

Color Legend:

State Machine Characteristics

Critical Routing Logic

• Condition A: {what triggers this path}
• Condition B: {what triggers this path}

---

## Pre-Diagram Checklist

Before creating the diagram, verify:

- [ ] LOADED `/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

- `/make-arch-diag` - Parent skill for lens selection
- `/mermaid` - MUST BE LOADED before creating diagram
- `/arch-lens-concurrency` - For parallel execution details
- `/arch-lens-error-resilience` - For failure handling specifics