Ascii Explainer

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name: ascii-explainer description: Explains code, algorithms, system design using ASCII diagrams. Trigger phrases - "explain visually", "I don't get it", "show me", "ascii diagram", "help me understand". Produces diagram-first explanations ending with TL;DR tables. license: MIT

Thinking

Before drawing, DIAGNOSE:

1. Mental Model Gap: What does user THINK vs what IS true? Name both.
2. Primitive: Which structure captures the essence? (see Quick Pick below)
3. Hierarchy: ONE main thing + 2-3 supporting details. Max 6 boxes.
4. Verify: Can diagram be understood WITHOUT surrounding text?

CRITICAL: Diagnosis IS the skill. Surfacing "user assumes X, but actually Y" is the value—not drawing boxes.

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Quick Pick (90% of cases)

If the concept has...	Use	ASCII Pattern
Steps in order	DAG	A → B → C
States + events	State Machine	[S1] --evt--> [S2]
Parent-child hierarchy	Tree	Root with / \ branches
Cycles/feedback	Graph	Arrows that loop back
Stages that transform	Pipeline	[Stage1] ──▶ [Stage2]
2D relationships	Matrix	Grid with ┌─┬─┐

For full primitive taxonomy → see PRIMITIVES.md

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Primitive Selection Flowchart

Continuous (infinite states)? ──Yes──▶ MANIFOLD
         │No
Time/order focused? ──Yes──▶ SEQUENCE│QUEUE│STACK│PIPELINE│TIMELINE
         │No
Concurrent states? ──Yes──▶ PETRI NET
         │No
States + transitions? ──Yes──▶ STATE MACHINE
         │No
Two distinct node types? ──Yes──▶ BIPARTITE
         │No
Edges connect 3+ nodes? ──Yes──▶ HYPERGRAPH
         │No
Partial ordering? ──Yes──▶ LATTICE
         │No
Spatial cells? ──Yes──▶ GRID
         │No
N-dimensional? ──Yes──▶ TENSOR/MATRIX
         │No
Direction matters? ──No──▶ UNDIRECTED GRAPH
         │Yes
Can loop back? ──Yes──▶ CYCLIC GRAPH
         │No
Multiple parents? ──Yes──▶ DAG
         │No──▶ TREE

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Process

1. Clarify (1 question max)

• What are the "things"? (nodes/states/events)
• What are the "connections"? (edges/transitions/order)
• Can you loop back?

If obvious, skip.

2. Identify Primitive

Use Quick Pick or flowchart. State: "This is a [PRIMITIVE] because [ONE REASON]."

3. Render ASCII

• Max 20 lines
• Use: ─ │ ┌ ┐ └ ┘ ├ ┤ ┬ ┴ ┼ ← → ↑ ↓ ● ○ █
• Label with user's domain terms

4. Verify

"Does this capture the structure? What's missing?"

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Output Structure

[1-line context]

┌─────────────────────────────────────┐
│     WHAT [USER/ISSUE] ASSUMES:      │
├─────────────────────────────────────┤
│  [Their mental model]               │
└─────────────────────────────────────┘

┌─────────────────────────────────────┐
│          ACTUAL STATE:              │
├─────────────────────────────────────┤
│  [Reality]                          │
│     ↑ key difference                │
└─────────────────────────────────────┘

Primitive: [NAME] — "[reason]"

[ASCII DIAGRAM]

┌─────────┬────────────┬─────────────┐
│ Aspect  │  Assumed   │   Actual    │
├─────────┼────────────┼─────────────┤
│ X       │ state A    │  state B    │
└─────────┴────────────┴─────────────┘

★ Insight ─────────────────────────────
[Transferable lesson]
───────────────────────────────────────

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Constraints

• Emoji sparingly: 🟣🔵🟢 for state, ✓✗⚠️ for status
• Nested concepts: 3-space indent
• Pointer annotations: ↑ or ← with 1-line labels
• Never: prose paragraphs first, box soup, mixed styles (+--+ with ┌──┐)