diff --git a/package.json b/package.json
index 10cffd12ce..e290cc0fc9 100644
--- a/package.json
+++ b/package.json
@@ -99,6 +99,7 @@
     "@typescript-eslint/parser": "^4.0.1",
     "babel-plugin-rewire-ts": "^1.4.0",
     "callsites": "^3.1.0",
+    "diff": "^4.0.1",
     "difflib": "^0.2.4",
     "es-check": "^6.0.0",
     "eslint": "^7.2.0",
diff --git a/tools/check-openapi b/tools/check-openapi
index 139bf0a6f1..c30ed98a81 100755
--- a/tools/check-openapi
+++ b/tools/check-openapi
@@ -4,6 +4,7 @@
 
 const fs = require("fs");
 
+const Diff = require("diff");
 const ExampleValidator = require("openapi-examples-validator");
 const Prettier = require("prettier");
 const SwaggerParser = require("swagger-parser");
@@ -64,7 +65,20 @@ async function checkFile(file) {
                 if (formatted !== node.value.value) {
                     ok = false;
                     const {line, col} = lineCounter.linePos(node.value.range[0]);
-                    console.error("%s:%d:%d: Format description with Prettier", file, line, col);
+                    console.error("%s:%d:%d: Format description with Prettier:", file, line, col);
+                    let diff = "";
+                    for (const part of Diff.diffLines(node.value.value, formatted)) {
+                        const prefix = part.added
+                            ? "\u001B[32m+"
+                            : part.removed
+                            ? "\u001B[31m-"
+                            : "\u001B[34m ";
+                        diff += prefix;
+                        diff += part.value.replace(/\n$/, "").replace(/\n/g, "\n" + prefix);
+                        diff += "\n";
+                    }
+                    diff += "\u001B[0m";
+                    console.error(diff);
                 }
             }
         },