feat: Added url output type (#26)

* feat: add mermaid ink url output types

* Address review feedback

Author: aakashH242

README.md

@@ -7,7 +7,9 @@ Generate <img src="https://mermaid.js.org/favicon.svg" height="14"/> [mermaid](h
 
 - Fully support all features and syntax of `Mermaid`.
 - Support configuration of `backgroundColor` and `theme`, enabling large AI models to output rich style configurations.
-- Support exporting to `base64`, `svg`, `mermaid`, and `file` formats, with validation for `Mermaid` to facilitate the model's multi-round output of correct syntax and graphics. Use `outputType: "file"` to automatically save PNG diagrams to disk for AI agents.
+
+- Support exporting to `base64`, `svg`, `mermaid`, `file`, and remote-friendly `svg_url`, `png_url` formats, with validation for `Mermaid` to facilitate the model's multi-round output of correct syntax and graphics. Use `outputType: "file"` to automatically save PNG diagrams to disk for AI agents, or the URL modes to share diagrams through public mermaid.ink links.
+
 
 <img width="720" alt="mcp-mermaid" src="https://mermaid.js.org/header.png" />
 

__tests__/tools/mermaid.json

@@ -22,8 +22,8 @@
       },
       "outputType": {
         "type": "string",
-        "enum": ["base64", "svg", "mermaid", "file"],
-        "description": "The output type of the diagram. Can be 'base64', 'svg', 'mermaid', or 'file'. Default is 'base64'. 'base64' returns PNG image as base64 encoded string. 'file' will save the PNG image to disk and return the file path.",
+        "enum": ["base64", "svg", "mermaid", "file", "svg_url", "png_url"],
+        "description": "The output type of the diagram. Can be 'base64', 'svg', 'mermaid', 'file', 'svg_url', or 'png_url'. Default is 'base64'. 'base64' returns PNG image as base64 encoded string. 'file' saves the PNG image to disk. The *_url options return public mermaid.ink links for remote-friendly sharing.",
         "default": "base64"
       }
     },

package.json

@@ -1,7 +1,7 @@
 {
   "name": "mcp-mermaid",
   "description": "❤️ Generate mermaid diagram and chart with AI MCP dynamically.",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "main": "build/index.js",
   "type": "module",
   "scripts": {

src/server.ts

@@ -14,7 +14,7 @@ import {
   startStdioMcpServer,
 } from "./services";
 import { schema, tool } from "./tools";
-import { renderMermaid } from "./utils";
+import { createMermaidInkUrl, renderMermaid } from "./utils";
 import { Logger } from "./utils/logger";
 
 /**
@@ -88,6 +88,18 @@ function setupToolHandlers(server: Server): void {
             ],
           };
         }
+        if (outputType === "svg_url" || outputType === "png_url") {
+          const variant = outputType === "svg_url" ? "svg" : "img";
+          const url = createMermaidInkUrl(mermaid as string, variant);
+          return {
+            content: [
+              {
+                type: "text",
+                text: url,
+              },
+            ],
+          };
+        }
         if (outputType === "file") {
           if (!screenshot) {
             throw new McpError(

src/tools/index.ts

@@ -23,9 +23,9 @@ C-->D;.`)
     .optional()
     .default("white"),
   outputType: z
-    .enum(["base64", "svg", "mermaid", "file"])
+    .enum(["base64", "svg", "mermaid", "file", "svg_url", "png_url"])
     .describe(
-      "The output type of the diagram. Can be 'base64', 'svg', 'mermaid', or 'file'. Default is 'base64'. 'base64' returns PNG image as base64 encoded string. 'file' will save the PNG image to disk and return the file path.",
+      "The output type of the diagram. Can be 'base64', 'svg', 'mermaid', 'file', 'svg_url', or 'png_url'. Default is 'base64'. 'base64' returns PNG image as base64 encoded string. 'file' saves the PNG image to disk. The *_url options return public mermaid.ink links for remote-friendly sharing.",
     )
     .optional()
     .default("base64"),

src/utils/index.ts

@@ -1,3 +1,5 @@
 export { zodToJsonSchema } from "./schema";
 export { renderMermaid } from "./render";
 export { Logger } from "./logger";
+export { createMermaidInkUrl } from "./mermaidUrl";
+

src/utils/mermaidUrl.ts

@@ -0,0 +1,25 @@
+import { deflateSync } from "node:zlib";
+
+/**
+ * Encodes mermaid text into the Base64URL deflated format used by mermaid.ink.
+ */
+
+function encodeMermaidToBase64Url(mermaid: string): string {
+  const compressed = deflateSync(mermaid, { level: 9 });
+  return compressed
+    .toString("base64")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=+$/g, "");
+}
+
+/**
+ * Creates a public mermaid.ink URL for the given mermaid definition.
+ */
+export function createMermaidInkUrl(
+  mermaid: string,
+  variant: "svg" | "img",
+): string {
+  const encoded = encodeMermaidToBase64Url(mermaid);
+  return `https://mermaid.ink/${variant}/pako:${encoded}`;
+}