Drawio Bpmn Skill for Claude

Draw.io BPMN

Produce correct BPMN (Business Process Model and Notation) swimlane diagrams in

draw.io. This skill is a thin frontend; the deterministic engine, validator, and

rules live in the drawio-ai-kit package, reached via the drawio-ai CLI.

0. Preflight — the CLI must be installed

command -v drawio-ai >/dev/null 2>&1 || echo "Install the Kit first:  npm i -g github:sparklabx/drawio-ai-kit"

If drawio-ai is not on PATH, stop and tell the user to run

npm i -g github:sparklabx/drawio-ai-kit. Never run npm i -g yourself — nothing mutates the

user's global environment without their say-so.

1. Delegate the build (preferred when your harness supports it)

If your harness can spawn autonomous subagents that run shell commands AND read

images (e.g. Claude Code's Task tool, a general-purpose agent), run the whole

build loop in a subagent — the rules, icon searches, and every render/fix

iteration then cost this conversation nothing. If it can't (or the subagent

can't read images), skip to Inline path below — same loop, same rules.

Before spawning, resolve what the subagent cannot ask about: diagram scope,

output directory (absolute path under the user's project), filename. Run the

preflight above yourself. For a multi-diagram request, spawn one subagent per

diagram in parallel with distinct filenames.

Model routing — if your harness lets you choose the subagent's model, route by

task weight: a fast/cheap tier (Claude Haiku-class — must support vision) when

the request matches a template from the rules' Templates table (reproduction is

mechanical; the validator's advice strings teach every fix), your **default strong

model** for free-hand or novel architectures. If a cheap subagent returns VALIDATE

not ok or ITERATIONS > 3, respawn ONCE on the strong model before taking over

inline. Multi-diagram requests: route each diagram independently.

Subagent prompt (fill every <...>):

Build a BPMN swimlane .drawio diagram with the drawio-ai CLI.
Request: <user's request + clarifications, verbatim>
Output: <ABS_PROJECT_DIR>/<NAME>.drawio — never write inside the Kit, never into cwd.
Follow exactly:
1. Set ROOT="$(drawio-ai root)". Read $ROOT/docs/api-cheatsheet.md — the full layout-engine
   API in one file; never read library source.
2. Run `drawio-ai workflow` and `drawio-ai principles --mode bpmn` — the source of
   truth. (Fallback if a command is blocked: read $ROOT/rules/*.md directly.)
3. Look up every icon with ONE batched `drawio-ai search "a, b, c"`; never recolor icons.
4. Scaffold, don't write: `drawio-ai scaffold --list`, pick the closest template, then
   `drawio-ai scaffold <name>.mjs -o <dir>/build.mjs` — the script arrives runnable
   (absolute imports, self-validating, self-rendering with an issues list). Edit only the
   deltas. If no template is close AND you'd change more than half of it, Write a new
   script instead (keep the scaffold's self-check tail). Layout engine only
   (group/frame/grid/icon/box + renderTree), NO hand-written coordinates.
5. Each `node build.mjs` run prints validate JSON AND the render's machine-readable
   `issues` list. Fix from THAT checklist — all issues in one Edit round — then re-run.
   Loop until issues is empty.
6. Only when issues is empty: Read the PNG once as final visual confirmation (list any
   remaining visual problems, fix ALL in one round). Target <= 2 PNG reads total. Then
   render once WITHOUT --check for the final deliverable PNG.
Do NOT invoke any drawio skill — this prompt already contains the full procedure.
Do not ask questions — make the standard choice and record it under ASSUMPTIONS.
Return EXACTLY this block, nothing else:
DRAWIO: <absolute path to .drawio>
PNG: <absolute path to .png>
VALIDATE: <verbatim final validate JSON>
ICONS: <comma-separated icon names used>
ITERATIONS: <number of render/fix cycles>
SUMMARY: <one sentence describing the diagram>
ASSUMPTIONS: <choices made without asking, or "none">

Relay DRAWIO, PNG and SUMMARY to the user verbatim; do NOT re-read the

.drawio or PNG in this conversation — the subagent already ran the vision

self-check. If VALIDATE is not ok, take over via the Inline path (the build

.mjs and .drawio are on disk at the returned paths).

Inline path (no subagent support)

1. Shared Workflow

drawio-ai workflow

Prints the build → validate → render → write-to-project-path loop every diagram

follows. Read it; it is the source of truth for the process.

2. Domain rules

drawio-ai principles --mode bpmn

Returns the BPMN rules + shared principles + catalog shape groups.

3. Build with the engine, then validate + render

Resolve the Kit's install dir, then import the engine by absolute path (the

Shared Workflow shows the exact pattern):

ROOT="$(drawio-ai root)"     # absolute path to the installed Kit

Build with the declarative layout engine (NO hand-written coordinates) using the

src/bpmn.mjs creators and the pool() primitive, then:

drawio-ai validate <file> → drawio-ai render <file> -o <file>.png (Read

the PNG for the vision self-check) → write the .drawio to an **absolute path

under the user's project** (never the Kit, never cwd).

Domain notes

Structure: pool → lanes (roles) × phases (milestones). Use the creators in

src/bpmn.mjs — start, intermediate, end, gateway (exclusive/parallel/

inclusive/event), typed tasks (userTask, serviceTask, manualTask,

scriptTask, businessRuleTask), plain task, subProcess. Each node carries

{ lane, col } cell tags; the engine places them automatically.

A gateway MUST split (≥2 outgoing) or merge (≥2 incoming) — never neither. Red

accent ONLY for blocker end events (error/cancel/terminate); everything else is

monochrome. Sequence flow: solid lines, rounded corners. One start event (no

incoming flow); end events on the right (no outgoing flow). Horizontal by default;

pass orientation: "vertical" to pool() for vertical swimlanes.

Self-check (before delivering)

• [ ] Built with the layout engine — no hand-written coordinates.
• [ ] drawio-ai validate → ok, no warnings, no advice.
• [ ] Every icon came from drawio-ai search (category colors intact).
• [ ] drawio-ai render vision self-check passed.
• [ ] Output written under the user's project, not the Kit.