tldraw-skill

name	tldraw-skill
description	Use when user requests diagrams, flowcharts, architecture charts, or visualizations. Also use proactively when explaining systems with 3+ components, complex data flows, or relationships that benefit from visual representation. Generates .tldr JSON files and exports to PNG/SVG locally using @kitschpatrol/tldraw-cli.
metadata	{"author":"Agents365-ai"}

tldraw Whiteboard Diagrams

Overview

Generate modern whiteboard-style diagrams as .tldr JSON files and export to PNG/SVG using @kitschpatrol/tldraw-cli. tldraw produces clean hand-drawn aesthetic diagrams with rich shape libraries and smooth arrow routing — well-suited for casual or whiteboard-style visualizations.

Format: .tldr JSON Export: PNG, SVG (via @kitschpatrol/tldraw-cli) Aesthetic: Hand-drawn whiteboard style by default; switchable to clean fonts via font prop.

When to Use

Explicit triggers: user says "diagram", "flowchart", "draw", "visualize", "whiteboard diagram", "tldraw diagram", "architecture diagram", "sketch this out".

Proactive triggers:

• Explaining a system with 3+ interacting components
• Describing a multi-step process, data flow, or pipeline
• Showing relationships between services/modules
• Architecture overviews, sequence flows, decision trees, ML model layers

Skip when: a simple list or table suffices, the user wants a polished business-presentation diagram (prefer drawio-skill), or the user is in a quick Q&A flow.

When NOT to use it — route elsewhere:

• Logos / solid-color graphics / filled icons: tldraw has no opaque fill (solid = light tint; white-on-dark can't be reproduced) → use the drawio skill or the original vector file.
• Precise vector geometry or strict (hollow-arrow) UML → drawio (or plantuml for UML).
• Auto-layout of many nodes → mermaid (tldraw needs manual coordinates).
• A pixel-faithful copy of an existing image → not a diagram-skill task.

Prerequisites

# Install tldraw-cli
npm install -g @kitschpatrol/tldraw-cli

# Verify
tldraw --version

Works identically on macOS, Windows, and Linux.

First-export note: tldraw export renders through a pinned Chrome build via puppeteer. The first export can fail with Could not find Chrome (ver. <x>). The error names the exact version it needs — install it once, then exports work:

# The error message names the version; substitute it here
npx puppeteer browsers install chrome@<version-from-error>

(Installs to ~/.cache/puppeteer; only needed once per CLI version.)

Workflow

Before starting, assess whether the user's request is specific enough. If key details are missing, ask 1-3 focused questions:

• Diagram type — which preset? (Architecture, Flowchart, Sequence, ML/DL, ERD, UML, or general)
• Output format — PNG (default), SVG?
• Output location — default is the user's working dir; honor any explicit path the user gives (e.g. "put it in ./artifacts/"). Don't ask if they didn't mention one.
• Scope/fidelity — how many components? Any specific technologies or labels?

Skip clarification if the request already specifies these details or is clearly simple (e.g., "draw a flowchart of X").

1. Check deps — verify tldraw --version succeeds; if missing, run npm install -g @kitschpatrol/tldraw-cli.
2. Plan — identify shapes (geo type per node), connections (arrows with source/target), and layout (TB or LR, group by tier/role). Sketch a coordinate grid before writing JSON.
3. Generate — write the .tldr JSON file. Default output dir is the user's working dir; if the user specified a path or directory (e.g. ./artifacts/), mkdir -p it first and write there. Apply the same dir choice to PNG/SVG exports in steps 4 and 7.
4. Export draft — run CLI to produce a PNG for preview.
5. Self-check — use the agent's built-in vision capability to read the exported PNG, catch obvious issues, auto-fix before showing the user (requires a vision-enabled model such as Claude Sonnet/Opus). If vision is unavailable, skip this step.
6. Review loop — show image to user, collect feedback, apply targeted JSON edits, re-export, repeat until approved.
7. Final export — export the approved version to all requested formats; report file paths for both the .tldr source and exported image(s).

Step 5: Self-Check

After exporting the draft PNG, use the agent's vision capability (e.g., Claude's image input) to read the image and check for these issues before showing the user. If the agent does not support vision, skip self-check and show the PNG directly.

tldraw's own AI agent flags exactly three structural defects — text overflow (a box too small for its label), overlapping text, and friendless arrows (an arrow with an unbound end). The first three rows below target those; size boxes correctly up front (see "Sizing boxes to fit labels") and they rarely occur.

Check	What to look for	Auto-fix action
Text overflow	Label spills past the shape's border, or the box looks taller than you set (tldraw auto-grows an undersized box)	Increase w/h to fit the label — see the sizing formula below
Overlapping text	Two text-bearing shapes' labels touch or overlap, hurting legibility	Shift shapes apart by ≥200px
Friendless arrow	An arrow with one end not connected to a shape (floats loose)	Bind both ends: every arrow's start and end need a boundShapeId matching an existing shape
Off-canvas shapes	Shapes at negative coordinates or far from the main group	Move to positive coordinates near the cluster
Arrow-shape overlap	An arrow visually crosses through an unrelated shape	Adjust bend value or move endpoints to a different normalizedAnchor side
Stacked arrows	Multiple arrows overlap each other on the same path	Distribute normalizedAnchor across the shape perimeter (use different x/y values)

• Max 2 self-check rounds — if issues remain after 2 fixes, show the user anyway.
• Re-export after each fix and re-read the new PNG.

Step 6: Review Loop

After self-check, show the exported image and ask the user for feedback.

Targeted edit rules — for each type of feedback, apply the minimal JSON change:

User request	JSON edit action
Change color of X	Find shape by props.text matching X, update props.color
Add a new node	Append a new shape record with next available index, position near related nodes
Remove a node	Delete the shape record and any arrow records bound to it
Move shape X	Update the shape's x/y fields
Resize shape X	Update props.w/props.h
Add arrow from A to B	Append a new arrow record binding to A and B's shape ids
Change label text	Update props.text on the matching shape or arrow
Change layout direction	Full regeneration — replan the grid and rebuild

Rules:

• For single-element changes: edit the existing JSON in place — preserves layout tuning from prior iterations.
• For layout-wide changes (e.g., swap LR↔TB, "start over"): regenerate full JSON.
• Overwrite the same {name}.png each iteration — do not create v1, v2, v3 files.
• After applying edits, re-export and show the updated image.
• Loop continues until user says approved / done / LGTM.
• Safety valve: after 5 iteration rounds, suggest the user open the .tldr file in tldraw.com or the desktop app for fine-grained adjustments.

---

File Format

Complete .tldr Skeleton

{
  "tldrawFileFormatVersion": 1,
  "schema": {
    "schemaVersion": 1,
    "storeVersion": 4,
    "recordVersions": {
      "asset": {"version": 1, "subTypeKey": "type", "subTypeVersions": {"image": 2, "video": 2, "bookmark": 0}},
      "camera": {"version": 1},
      "document": {"version": 
        
        
        
                                     
        
        
    
  
   
             
             
    
  

Critical rules:

• document:document and page:page1 records are ALWAYS required.
• All shapes go in the records array after the page record.
• All shapes have "parentId": "page:page1".
• Shape IDs use format "shape:xxx" with unique suffix (e.g., "shape:s1", "shape:a1").
• index values are fractional-index keys. Use "a" + one base-62 character, in order: "a0"–"a9", then "aA"–"aZ", then "aa"–"az" (62 ordered keys — enough for any normal diagram).
• Do not append a second character: "a10" is invalid. And never use a leading "b"/"c" ("b1", "c1", "b0") — those encode a longer integer part, so they are malformed fractional keys and trigger invalidRecords. Stick to the single-character "a*" keys above.

---

Geo Shape Record

{
  "id": "shape:s1",
  "typeName": "shape",
  "type": "geo",
  "parentId": "page:page1",
  "index": "a1",
  "x": 100,
  "y": 100,
  "rotation": 0,
  "isLocked": false,
  "opacity": 1,
  "meta": {},
  "props": {
    "w": 180,
    "h": 60,
    "geo": "rectangle"
     
     
     
     
     
     
     
     
     
     
     
  

Geo Types

geo value	Use for
rectangle	services, modules, components
ellipse	databases, start/end nodes
oval	pill-shaped start/end terminators (flowcharts)
diamond	decision points
cloud	external services, infrastructure
hexagon	event hubs, message buses
triangle	gateways, load balancers
star	highlights, key features
pentagon	stages, milestones
octagon	stop / terminal / blocking states
trapezoid	manual operations, transforms
rhombus / rhombus-2	parallelograms — I/O steps (left/right slant)
arrow-right / arrow-left / arrow-up / arrow-down	directional flow blocks, data movement
x-box	failed / invalid / rejected states (box with ✕)
check-box	passed / validated / done states (box with ✓)
heart	accents (rarely needed for technical diagrams)

All 20 geo values are valid; the above are the useful subset for technical diagrams.

Color Palette

color	Use for
blue	clients, core services
green	success, databases, storage
orange	queues, event buses, warnings
red	external APIs, errors, alerts
light-red	soft alerts, secondary warnings
violet	gateways, security, auth
yellow	decisions, caches
grey	neutral, background, legacy
light-blue	secondary services, metadata
light-violet	soft auth/security, secondary gateways
light-green	soft success, secondary storage
white	blank/empty nodes, placeholders (pair with fill: solid)
black	titles, emphasis

Full palette (13): black, grey, light-violet, violet, blue, light-blue, yellow, orange, green, light-green, light-red, red, white.

Style Options

Property	Values	Notes
fill	semi, solid, none, pattern	semi = tinted fill (recommended)
dash	draw, solid, dashed, dotted	draw = hand-drawn default
size	s, m, l, xl	m = default
font	draw, sans, serif, mono	draw = default whiteboard style

---

Arrow Record

{
  "id": "shape:a1",
  "typeName": "shape",
  "type": "arrow",
  "parentId": "page:page1",
  "index": "aG",
  "x": 0,
  "y": 0,
  "rotation": 0,
  "isLocked": false,
  "opacity": 1,
  "meta": {},
  "props": {
    "dash": "draw",
    "size": "m",
    "fill": "none"
     
     
     
     
       
       
          
       
    
     
       
       
          
       
    
     
     
     
     
  

Arrow Connection Rules

• Arrow record x and y are always 0, 0.
• Use "type": "binding" with boundShapeId to connect to a specific shape.
• normalizedAnchor specifies WHERE on the target shape the arrow connects (0–1 range):
  • {x: 0.5, y: 0} = top center
  • {x: 0.5, y: 1} = bottom center
  • {x: 0, y: 0.5} = left center
  • {x: 1, y: 0.5} = right center
  • {x: 0.5, y: 0.5} = center
• Add "text": "label" in arrow props for labeled connections.
• Use "bend": 20 (or -20) for slight curves to avoid overlap with other arrows.
• For dashed/dotted arrows (e.g., async flows, optional links), set "dash": "dashed" or "dotted".
• Set "spline": "cubic" for a smooth curved arrow (default "line" is straight/elbow). Useful for skip connections and back-edges.

Arrowheads

arrowheadStart and arrowheadEnd each accept any of these 9 values (all render in @kitschpatrol/tldraw-cli):

Value	Looks like	Use for
none	(no head)	start of a one-way arrow
arrow	open V	default flow direction
triangle	filled ▶	UML inheritance / "is-a"
diamond	filled ◆	UML composition / aggregation (on the owner end)
dot	●	sequence-diagram message endpoints
square	■	terminal / fixed endpoint
bar	|	"stop" / boundary marker
pipe	||	alternative boundary marker
inverted	hollow V	de-emphasized direction

Default arrows use "arrowheadStart": "none", "arrowheadEnd": "arrow". For bidirectional links set both ends to "arrow".

Distributing Arrows on a Shape

When multiple arrows connect to the same shape, assign different normalizedAnchor points to prevent stacking:

Position	x	y	Use when
Top center	0.5	0	connecting to node above
Top-left	0.25	0	2nd connection from top
Top-right	0.75	0	3rd connection from top
Right center	1	0.5	connecting to node on right
Bottom center	0.5	1	connecting to node below
Left center	0	0.5	connecting to node on left

Rule: if a shape has N connections on one side, space them evenly (e.g., 3 connections on bottom → x = 0.25, 0.5, 0.75).

Multiple Arrows Between the Same Two Nodes

The anchor-distribution rule above spreads arrows going to different nodes. When N arrows connect the same pair (e.g., bidirectional request/response, or several relationships A↔B), anchors can't separate them — instead spread the bend values symmetrically so the arrows fan out into distinct arcs:

• Pick a max bend amount (≈ 30–60; larger for nodes that are far apart).
• Assign the N arrows bends evenly spaced from −amount to +amount:
  • 2 arrows → bend: -amount, bend: +amount
  • 3 arrows → bend: -amount, 0, +amount
  • General: bend[i] = -amount + i * (2*amount / (N-1)) for i = 0..N-1
• A straight arrow plus a single curved one (bend: 0 and bend: 40) reads cleanly for a request/response pair.

---

Container & Annotation Shapes

Beyond geo and arrow, two more shape types are useful for technical diagrams.

Frame (labeled container — tiers, subsystems, swimlanes)

A frame is a native rectangular container with a title. Use it to group a tier or subsystem with a visible boundary; stack several frames to approximate swimlanes.

{
  "id": "shape:frame1", "typeName": "shape", "type": "frame",
  "parentId": "page:page1", "index": "a1",
  "x": 60, "y": 60, "rotation": 0, "isLocked": false, "opacity": 1, "meta": {},
  "props": { "w": 360, "h": 220, "name": "Backend Tier"   

• props.name is the title shown at the frame's top-left.
• Child shapes set "parentId": "shape:frame1" (not page:page1), and their x/y are relative to the frame's top-left corner, not the page. A child at x: 40, y: 60 sits 40px in and 60px down from the frame's origin.
• Frames render as a clean (non-hand-drawn) rectangle — good for structural grouping. Arrows can still bind across frames normally.

Note (sticky-note annotation / callout)

A note is a sticky note — ideal for TODOs, callouts, and comments layered onto a diagram.

{
  "id": "shape:n1", "typeName": "shape", "type": "note",
  "parentId": "page:page1", "index": "a4",
  "x": 480, "y": 80, "rotation": 0, "isLocked": false, "opacity": 1, "meta": {},
  "props": { "color": "yellow", "size": "m", "text": "TODO: add retry\nlogic here"
         
              

• A note has no w/h — it's a fixed square (~200px) that auto-grows for longer text. Don't add w/h.
• yellow is the classic sticky color; any palette color works.
• Use notes sparingly — for annotations about the diagram, not as primary nodes (use geo for those).

---

Index Ordering Rules

Indices control z-order (stacking). Use this sequence:

a1, a2, a3, a4, a5, a6, a7, a8, a9,
aA, aB, aC, aD, aE, aF, aG, aH, aI, aJ, aK, aL, aM,
aN, aO, aP, aQ, aR, aS, aT, aU, aV, aW, aX, aY, aZ,
aa, ab, ac, ... az          ← continue here past aZ; never "a10"

• Geo shapes first: a1 through aF (or as many as needed).
• Arrow shapes after: aG, aH, etc.
• Every shape must have a unique index.

---

Layout Tips

Spacing — scale with complexity:

Diagram complexity	Nodes	Horizontal gap	Vertical gap
Simple	≤5	200px	150px
Medium	6–10	280px	200px
Complex	>10	350px	250px

Sizing boxes to fit labels (do this up front, not in self-check): the draw font is wide. Compute w/h from the label so text never clips. Approximate per-character width and line height for the default draw font:

size	char width (px)	line height (px)
s	11	18
m (default)	15	28
l	22	40
xl	32	56

With padding = 16 on each side:

• w = ceil(longest_line_chars * char_width + 2*padding), then round up to the next multiple of 10.
• h = ceil(num_lines * line_height + 2*padding), rounded up to a multiple of 10.

Example: a size-m box labeled "API Gateway" (11 chars, 1 line) → w ≈ 11*15 + 32 = 197 → 200, h ≈ 28 + 32 = 60. Multi-line labels (with \n) count the longest line for w and the line count for h. Err slightly large — extra padding looks fine, a too-narrow box hard-wraps a word mid-letters.

Why this matters: if a box is too short for its text, tldraw silently grows it taller on render (it sets the shape's growY) — so the box ends up bigger than the h you wrote and collides with whatever you placed below it. Sizing correctly up front keeps growY at 0 and your layout intact. This is the single most common cause of "the diagram looks cramped / boxes overlap" after export.

Routing corridors: between shape rows/columns, leave an extra ~80px empty corridor where arrows can route without crossing other shapes. Never place a shape in a gap that arrows need to traverse.

Grid alignment: snap all x, y, w, h values to multiples of 10 — this matches tldraw's default gridSize: 10 and makes manual editing easier.

General rules:

• Plan the grid before assigning x/y coordinates — sketch node positions mentally first.
• Group related nodes in the same horizontal or vertical band.
• Place heavily-connected "hub" nodes centrally so arrows radiate outward instead of crossing.
• For wide shapes (like an API Gateway spanning multiple downstream services), set w to cover the full span.
• Center-align a child node under its parent (same center x) to avoid diagonal routing.
• Event bus pattern: place the bus (hexagon) in the center of the service row, not below — services on either side reach it with short horizontal arrows (normalizedAnchor.x = 1 left side, 0 right side), eliminating crossings.
• Horizontal connections never cross vertical nodes in the same row; use them for peer-to-peer and publish connections.

Avoiding arrow-shape overlap:

• Before finalizing coordinates, trace each arrow path mentally — if it must cross an unrelated shape, either move the shape or use bend to curve around.
• For tree/hierarchical layouts: assign nodes to layers (rows), connect only between adjacent layers to minimize crossings.
• For star/hub layouts: place the hub center, satellites around it — arrows stay short and radial.

---

Diagram Type Presets

When the user requests a specific diagram type, apply the matching preset below for shapes, colors, and layout conventions.

Architecture Diagram

Element	geo	color	Notes
Client (web/mobile)	rectangle	blue	Top row, label by client type
Service / module	rectangle	blue	Mid rows, group by tier
Database	ellipse	green	Bottom row, one per service
Cache	ellipse	yellow	Sits beside its owning service
Queue / event bus	hexagon	orange	Center of service row for hub pattern
Gateway / load balancer	triangle	violet	Above services
External API	cloud	red	Edge of canvas, dashed arrows in
Auth / security	rectangle	violet	Often near gateway

Layout: TB or LR by tier count; ≥4 tiers → TB. Hub nodes centered. Spacing scales with complexity (see table above).

Flowchart

Element	geo	color	Notes
Start / End	ellipse	green	Always at top and bottom
Process step	rectangle	blue	Default action box
Decision	diamond	yellow	Always label outgoing arrows (Yes / No)
I/O	rectangle (with dash: dashed)	orange	Distinguish from process via dashed border
Subprocess	rectangle	violet	Indicates a callable sub-flow

Layout: TB, ~200px vertical gap. Decisions branch left/right, then merge back to center. Always label decision branches in the arrow's props.text.

Sequence Diagram

tldraw doesn't have native lifeline shapes. Approximate with:

Element	geo	color	Notes
Actor / object header	rectangle	blue	Top of column
Lifeline	rectangle (w: 2, fill: solid, color: grey)	grey	Thin vertical line under each actor header
Sync message	arrow with arrowheadEnd: arrow	black	Solid horizontal arrow
Async message	arrow with dash: dashed	black	Dashed horizontal arrow
Return message	arrow with dash: dashed, color: grey	grey	Grey dashed

Layout: LR for actors (200–280px apart), TB for time. Each message is a horizontal arrow between two lifelines at increasing y.

ML / Deep Learning Model Diagram

For neural network architecture diagrams — useful for paper figures and explainers.

Element	geo	color	Notes
Input / Output	rectangle	green	Top and bottom of stack
Conv / Pooling	rectangle	blue	Standard layer block
Attention / Transformer	rectangle	violet	Distinct color for self-attention blocks
RNN / LSTM / GRU	rectangle	yellow	Recurrent layers
FC / Linear	rectangle	orange	Dense projection layers
Loss / Activation	rectangle	red	Final loss / softmax / activation
Skip connection	arrow with bend: 30, dash: dashed	grey	Curved dashed bypass

Tensor shape annotation: include the dimensions in props.text on a second line. tldraw renders \n literally inside JSON strings, so use a real newline (the JSON encoder will write \n):

"text": "Conv2D\n(B, 64, 32, 32)"

Layout: TB (data flows top → bottom), layers ~150px apart. Skip connections curve around the main stack.

ER Diagram (ERD)

tldraw lacks native table/row shapes. Approximate each entity as a tall rectangle with multi-line text.

Element	geo	color	Notes
Entity	rectangle (fill: solid, color: light-blue)	light-blue	Title + columns as one multi-line text label
Column list	embedded in props.text with \n between rows	—	Mark PK with * prefix, FK with >
Relationship	arrow with arrowheadStart: arrow, arrowheadEnd: arrow	black	Both ends arrowed for many-to-many
Optional / weak relationship	arrow with dash: dashed	grey	Dashed for optional FK

Label the arrow with cardinality (e.g., 1..*, 0..1) via props.text.

Layout: TB or grid; entities spaced ≥300px apart to leave room for column lists.

UML Class Diagram

Element	geo	color	Notes
Class	rectangle (fill: solid, color: light-blue)	light-blue	Title + attributes + methods as one multi-line text
Inheritance	arrow with arrowheadEnd: triangle	black	tldraw renders a filled triangle arrowhead — point it at the parent class
Composition	arrow with arrowheadStart: diamond, arrowheadEnd: none	black	tldraw renders a filled diamond head — put it on the owner (whole) end
Aggregation	arrow with arrowheadStart: diamond	black	Same diamond head; distinguish from composition via a label or note
Association	arrow with arrowheadEnd: arrow	black	Standard arrow

Note: tldraw's triangle/diamond arrowheads are filled, whereas strict UML uses hollow triangles (inheritance) and either filled/hollow diamonds (composition/aggregation). The shapes read correctly for sketches and explainers; for publication-grade UML with hollow heads, drawio-skill (separate skill) is a better fit.

Layout: TB, classes ~250px apart, interfaces above implementations.

---

Export Commands

# Check CLI version
tldraw --version

# PNG at 2x scale (recommended) — outputs diagram.png in ./
tldraw export diagram.tldr -f png --scale 2 -o ./

# SVG — outputs diagram.svg in ./
tldraw export diagram.tldr -f svg -o ./

# Transparent background
tldraw export diagram.tldr -f png --scale 2 --transparent -o ./

# Dark theme
tldraw export diagram.tldr -f png --scale 2 --dark -o ./

# Custom output directory (e.g. CI artifacts dir) — create if missing, then export there
mkdir -p ./artifacts && tldraw export diagram.tldr -f png --scale 2 -o ./artifacts/

Note: -o is an output directory, not a file path. The output file is named after the input file (diagram.tldr → diagram.png).

Auto-launch after export

Offer to open the .tldr file in the user's default tldraw viewer/editor:

OS	Command
macOS	open diagram.tldr
Linux	xdg-open diagram.tldr
Windows	start diagram.tldr

Or upload to https://tldraw.com (drag-and-drop the .tldr file) for browser editing.

---

Common Mistakes

Mistake	Fix
tldraw command not found	Run npm install -g @kitschpatrol/tldraw-cli
Could not find Chrome (ver. X) on export	Install the pinned build: npx puppeteer browsers install chrome@X (use the exact version from the error)
invalidRecords on export	Use single-character a keys (a1…a9, aA…aZ, aa…az); a10, b1, c1 are malformed fractional-index keys
Blank/empty export	Verify document:document and page:page1 records are present
Output file not found	-o is a directory; file name matches input: tldraw export foo.tldr -o ./ → ./foo.png
Arrow doesn't appear	Use "type": "binding" with boundShapeId; set arrow x/y to 0,0
Shapes overlap	Plan a 200px+ grid before assigning x/y; scale spacing with complexity
Box taller than expected / collides below	Label overflowed an undersized box, so tldraw auto-grew it (growY). Size w/h to the label up front using the sizing formula
Text not visible	Check props.text is set; if fill: "none", ensure text color contrasts
Index collision	All shapes must have unique index values
Shape ID clash	Use unique IDs: "shape:s1", "shape:s2", "shape:a1", etc.
Export fails	Ensure the .tldr file is valid JSON: python3 -m json.tool file.tldr > /dev/null

---

Fallback Chain

When tools are unavailable, degrade gracefully:

Scenario	Behavior
tldraw-cli missing	Generate .tldr JSON only; instruct user to drag-and-drop into https://tldraw.com or install the CLI
Vision unavailable for self-check	Skip self-check (step 5); proceed directly to showing user the exported PNG
Export fails	Validate JSON with python3 -m json.tool; deliver the .tldr file and suggest opening in tldraw.com

---

Source: Agents365-ai/tldraw-skill — distributed by TomeVault.