Markdown Diagram Renderer

markdown.render_diagrams

ProductionEngine wrapper (Class A)verifiablemoderatev1.0.0

File inputNo network

Overview

You send Markdown containing exact ```mermaid fenced blocks. An evidence-backed allowlist of 25 Mermaid families is rendered by an identity-bound isolated worker and sanitized with a closed SVG policy. Unsupported families, caller configuration, HTML labels, scripts, click directives, URLs, CSS, and arbitrary Mermaid options are rejected. Other code fences remain ordinary code. Accepts file input via file_ref — no need to extract file content first.

Mermaid needs an isolated deterministic runtime and a separate closed SVG security boundary; ordinary Markdown rendering cannot safely provide that.

Reliability

STRICT for Mermaid 11.16.0, the pinned light DOM, Noto Sans package, worker identity, parser, theme, and SVG policy. The allowlist is closed and evidence-backed from the full-family spike: 25 SUPPORTED, kanban deferred as SUPPORTED_WITH_LIMITS, and remaining families UNSUPPORTED with proved reasons. Failures include DIAGRAM_SYNTAX_INVALID, DIAGRAM_TYPE_UNSUPPORTED, RENDERER_BUSY, RENDER_TIMEOUT, INTERNAL_RENDERER_UNAVAILABLE, DIAGRAM_SANITIZATION_FAILED, OUTPUT_LIMIT_EXCEEDED, MARKDOWN_INVALID_ENCODING (re-encode the source as UTF-8), and MARKDOWN_COMPLEXITY_LIMIT (split or simplify a document exceeding the fixed node or nesting cap).

Context footprint

At most 50 diagrams, 50000 characters per diagram, 1000000 bytes per SVG, 2000000 aggregate output bytes, and 30000 ms per diagram. A successful call costs 5 execution credits.

When to use it

When a Markdown document contains one of the 25 evidence-backed Mermaid families.

When diagrams need interaction, external resources, caller configuration, or a Mermaid family outside the SUPPORTED allowlist (for example gantt, mindmap, sankey, architecture, kanban, flowchart-elk). Upstream Mermaid support alone does not make a family supported here.

Scope

Note

Renders supported Mermaid fenced blocks inside one Markdown document.

Non-goals

No arbitrary Mermaid configuration
No HTML labels
No click handlers
No URL loading
No caller CSS
No diagrams outside exact mermaid fences

Properties

IdempotentRetry safeStreaming supportedFile input supportedRequires external service

Capabilities

document-processingformatting

Cost & billing

Flat rate per invocation

MetercallsBillable onsuccessCost per call5 credits

File handling

Accepts file_refProduces file_refMax input488.3 KBMax file size488.3 KB

File limits

Constraints this skill applies to your input and generated files. The “Limited by” column shows the static source of each cap; none of these can be raised by upgrading your plan.

Limit	Value	Limited by
Maximum size per input file	488.3 KiB	Skill maximum

How we handle your data

Sensitive output possible

What this means

This skill may receive sensitive content and may return submitted, transformed, extracted, or reformatted content.

Squillify guarantees

Runs inside Squillify using a self-contained open-source component
This skill runs inside Squillify.
Payloads are not sent to an external service by this skill.
Self contained open source component
Squillify does not permanently store submitted payloads.
Telemetry records metadata only, not submitted content.
Submitted payloads are not used for training.
Submitted payloads are not reviewed by humans.
This skill does not target sensitive data.
The response may contain submitted or transformed content.

Your responsibility

Squillify does not determine whether submitted content is sensitive. Your application is responsible for deciding what data it is allowed to submit. Your application is responsible for securing the response.

Read the Microskill Data Handling Policy

Input schema

Field	Type	Required	Description
markdown	string	No	Inline Markdown up to 200000 characters. Required unless file_ref is present; omit only when file_ref is present. If both are present, file_ref wins and _meta._input_conflict_resolved reports it.
file_ref	string	No	Tenant-scoped strict UTF-8 Markdown file up to 500000 bytes. When omitted, the inline markdown field is used.
profile	string	No	commonmark, gfm, or squillify-safe; defaults to squillify-safe.
theme	string	No	squillify (default) applies the fixed Squillify Design System palette and document chrome; neutral, default, or dark preserve Mermaid's legacy palettes.
includeCss	boolean	No	Embed the scoped Squillify Design System stylesheet when theme is squillify; defaults to true.
includeSource	boolean	No	Include original Mermaid source in each diagram object; defaults to false.
errorPolicy	string	No	preserve_source (default) keeps invalid fences with a warning; fail rejects the call.
accessibility	object	No	Optional bounded plain-text title and description applied to accessible SVG; when omitted, no caller accessibility override is applied.
maxDiagrams	integer	No	Maximum accepted diagrams, 1..50; defaults to 50.
timeoutMs	integer	No	Per-diagram worker timeout, 1..30000 milliseconds; defaults to 5000.

Output schema

Field	Type	Required	Description
html	string	Yes	Sanitized rendered Markdown HTML.
diagrams	array	Yes	From 0 through 50 closed sanitized diagram result objects in source order.
warnings	array	Yes	From 0 through 50 closed skipped-diagram warning objects in source order.
_meta	object	Yes	Closed receipt containing parser, renderer, sanitization, and bounded-execution provenance.

API contract

POST /v1/execute

curl

curl -sS -X POST "$BASE/v1/execute" -H "Authorization: Bearer $KEY" -H 'Content-Type: application/json' -d '{"skillKey":"markdown.render_diagrams","input":{"markdown":"```mermaid\nflowchart LR\nA --> B\n```"}}'

Integrations

TypeScript SDK

import { Squillify } from "@squillify/sdk";

const sq = new Squillify({ apiKey: process.env.SQUILLIFY_API_KEY });

const { output } = await sq.execute("markdown.render_diagrams", {"includeCss":false,"accessibility":{"title":"Flow","description":"A to B"},"markdown":"```mermaid\nflowchart LR\nA --> B\n```"});

Errors

Code	HTTP	Retryable	Description
VALIDATION_ERROR	400	No	The request payload failed schema validation.
UNAUTHORIZED	401	No	Missing or invalid API key.
SKILL_NOT_ACCESSIBLE	403	No	The API key is not granted access to this skill.
SKILL_NOT_AVAILABLE_FOR_PLAN	403	No	This skill is not included in your current plan.
PLAN_ELIGIBILITY_UNAVAILABLE	503	Yes	Plan eligibility could not be decided. Retry after backoff.
SKILL_NOT_FOUND	404	No	The requested skill or version does not exist.
TENANT_RATE_LIMITED	429	Yes	Request rate limit exceeded. Retry after backoff.
QUOTA_EXCEEDED	429	Yes	Plan quota exhausted. Retryable once the quota period resets.
EXECUTION_TIMEOUT	504	Yes	Execution exceeded the allowed time budget.
DIAGRAM_SYNTAX_INVALID	400	No	The request payload failed this skill's input validation.
DIAGRAM_TYPE_UNSUPPORTED	400	No	The request payload failed this skill's input validation.
RENDERER_BUSY	429	Yes	A size, quota, rate, or time limit was exceeded.
RENDER_TIMEOUT	503	Yes	A dependency required by this skill is unavailable.
INTERNAL_RENDERER_UNAVAILABLE	503	Yes	A dependency required by this skill is unavailable.
DIAGRAM_SANITIZATION_FAILED	500	No	The skill encountered an unexpected execution failure.
MARKDOWN_INVALID_ENCODING	400	No	The request payload failed this skill's input validation.
MARKDOWN_COMPLEXITY_LIMIT	429	No	A size, quota, rate, or time limit was exceeded.

Other limits

Limit	Value
Recommended inline bytes	32 KiB

Limitations

No arbitrary Mermaid configuration
No HTML labels
No click handlers
No URL loading
No caller CSS
No diagrams outside exact mermaid fences
Interactive diagrams
Custom Mermaid themes
Untrusted external resources

How to call

POST /v1/execute (requires authentication)

Request bodyjson

{
  "skillKey": "markdown.render_diagrams",
  "input": {
    "includeCss": false,
    "accessibility": {
      "title": "Flow",
      "description": "A to B"
    },
    "markdown": "```mermaid\nflowchart LR\nA --> B\n```"
  }
}

Examples

Render a flowchart

Inputjson

{
  "includeCss": false,
  "accessibility": {
    "title": "Flow",
    "description": "A to B"
  },
  "markdown": "```mermaid\nflowchart LR\nA --> B\n```"
}

Expected outputjson

{
  "_meta": {
    "themeVersion": "sqfy-markdown-v2",
    "_input_conflict_resolved": false,
    "inputChars": 23,
    "rendererVersion": "11.16.0",
    "parserVersion": "0.24.0",
    "sanitized": true,
    "diagramCount": 1,
    "truncated": false,
    "parser": "commonmark",
    "cssIncluded": false,
    "inputBytes": 23,
    "renderer": "mermaid",
    "profile": "squillify-safe",
    "theme": "squillify",
    "nodeCount": 2,
    "profileVersion": "1"
  },
  "warnings": [],
  "diagrams": [
    {
      "index": 0,
      "type": "flowchart",
      "svg": "<svg xmlns=\"http://www.w3.org/2000/svg\" role=\"img\">...</svg>",
      "sourceRange": {
        "start": {
          "line": 1,
          "offset": 0,
          "column": 1
        },
        "end": {
          "line": 4,
          "offset": 35,
          "column": 4
        }
      },
      "title": "Flow",
      "description": "A to B",
      "error": null
    }
  ],
  "html": "<article class=\"sqfy-markdown sqfy-markdown-v2 sqfy-theme-squillify sqfy-markdown-diagrams\"><div class=\"sqfy-diagram-slot\"><figure>...</figure></div></article>"
}

Preserve source for a rejected diagram