Markdown Validator

Overview

You send Markdown and we return stable, source-positioned diagnostics without changing the document or rendering HTML. Choose CommonMark, GFM, or squillify-safe, and select the rule families you need. The validator checks syntax, references, security policy, accessibility, and profile compatibility. It never follows links, fetches assets, or contacts MathJax; math validation is structural only. Use markdown.render when you need sanitized HTML. Accepts file input via file_ref — no need to extract file content first.

A parser can recover malformed Markdown into ordinary text, so a safe pre-publication check needs both the parsed structure and the original source.

When to use it

Scope

Non-goals

• Does not render or rewrite the document
• Does not test whether remote links or images are reachable
• Does not typeset or semantically validate TeX
• Does not repair malformed Markdown

Properties

Capabilities

Cost & billing

Flat rate per invocation

File handling

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.

How we handle your data

Input schema

Output schema

API contract

curl -sS -X POST "$BASE/v1/execute" -H "Authorization: Bearer $KEY" -H 'Content-Type: application/json' -d '{"skillKey":"markdown.validate","input":{"markdown":"# Title\n\n![](x.png)"}}'

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

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

const { output } = await sq.execute("markdown.validate", {"markdown":"# Title\n\n![](x.png)"});

Errors

Other limits

Limitations

• Does not render or rewrite the document
• Does not test whether remote links or images are reachable
• Does not typeset or semantically validate TeX
• Does not repair malformed Markdown
• Checking whether external URLs are online
• Producing a browser-ready preview
• Automatically fixing formatting
• Validating TeX semantics

How to call

POST /v1/execute (requires authentication)

{
  "skillKey": "markdown.validate",
  "input": {
    "markdown": "# Title\n\n![](x.png)"
  }
}

Examples

{
  "markdown": "# Title\n\n![](x.png)"
}

{
  "warnings": 1,
  "valid": true,
  "_meta": {
    "profile": "squillify-safe",
    "truncated": false,
    "profileVersion": "1",
    "parser": "commonmark",
    "parserVersion": "0.24.0",
    "inputChars": 19,
    "inputBytes": 19,
    "nodeCount": 4,
    "rulesRun": 10
  },
  "diagnostics": [
    {
      "range": {
        "start": {
          "line": 3,
          "offset": 9,
          "column": 1
        },
        "end": {
          "line": 3,
          "offset": 19,
          "column": 11
        }
      },
      "suggestion": "Add concise alternative text inside the image brackets.",
      "code": "MARKDOWN_IMAGE_ALT_MISSING",
      "severity": "warning",
      "message": "The image has no alternative text."
    }
  ],
  "errors": 0
}

{
  "rulesets": [
    "accessibility"
  ],
  "failFast": true,
  "markdown": "# Start\n\n### Detail"
}

{
  "warnings": 1,
  "valid": true,
  "_meta": {
    "profile": "squillify-safe",
    "truncated": false,
    "profileVersion": "1",
    "parser": "commonmark",
    "parserVersion": "0.24.0",
    "inputChars": 19,
    "inputBytes": 19,
    "nodeCount": 4,
    "rulesRun": 3
  },
  "diagnostics": [
    {
      "range": {
        "start": {
          "line": 3,
          "offset": 9,
          "column": 1
        },
        "end": {
          "line": 3,
          "offset": 19,
          "column": 11
        }
      },
      "suggestion": "Use the next heading level to preserve document structure.",
      "code": "MARKDOWN_HEADING_LEVEL_SKIPPED",
      "severity": "warning",
      "message": "The heading level jumps from 1 to 3."
    }
  ],
  "errors": 0
}

Recommended use cases

• Check generated documentation before publishing it
• Find missing image descriptions and broken reference definitions
• Enforce one Markdown profile across a content pipeline
• Inspect a stored Markdown file without rendering it

Avoid for

• Checking whether external URLs are online
• Producing a browser-ready preview
• Automatically fixing formatting
• Validating TeX semantics

Related skills

Composable with

Safety & privacy

• Runs without calling any external service.
• Your payloads are never stored permanently.
• Telemetry captures metadata only — never your payload contents.
• We never train models on your payloads.
• No human reviews your payloads.

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