fix: serialize skill scaffold YAML safely 🤖🤖🤖

eng/create-skill.mjs

@@ -3,6 +3,7 @@
 import fs from "fs";
 import path from "path";
 import readline from "readline";
+import { dump } from "js-yaml";
 import { SKILLS_DIR } from "./constants.mjs";
 
 const rl = readline.createInterface({
@@ -107,10 +108,12 @@ async function createSkillTemplate() {
     fs.mkdirSync(skillFolder, { recursive: true });
 
     // Create SKILL.md template
+    const frontmatter = dump(
+      { name: skillName, description },
+      { forceQuotes: true, quotingType: "'", lineWidth: -1 }
+    );
     const skillMdContent = `---
-name: ${skillName}
-description: ${description}
----
+${frontmatter}---
 
 # ${skillTitle}
 

eng/create-skill.test.mjs

@@ -0,0 +1,106 @@
+import assert from "node:assert/strict";
+import { spawn } from "node:child_process";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { test } from "node:test";
+import { fileURLToPath } from "node:url";
+import { load } from "js-yaml";
+
+const engDir = path.dirname(fileURLToPath(import.meta.url));
+
+async function createSkill(t, description) {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "create-skill-"));
+  const modulesLink = path.join(root, "node_modules");
+  const scriptDir = path.join(root, "eng");
+  fs.mkdirSync(scriptDir);
+  for (const file of ["create-skill.mjs", "constants.mjs"]) {
+    fs.copyFileSync(path.join(engDir, file), path.join(scriptDir, file));
+  }
+  fs.symlinkSync(
+    path.join(engDir, "..", "node_modules"),
+    modulesLink,
+    process.platform === "win32" ? "junction" : "dir"
+  );
+
+  const child = spawn(
+    process.execPath,
+    [
+      path.join(scriptDir, "create-skill.mjs"),
+      "--name",
+      "yaml-roundtrip",
+      "--description",
+      description,
+    ],
+    { cwd: root, stdio: ["pipe", "pipe", "pipe"] }
+  );
+  t.after(async () => {
+    if (child.exitCode === null && child.signalCode === null) {
+      const closed = new Promise((resolve) => child.once("close", resolve));
+      child.kill();
+      await closed;
+    }
+    // Unlink the junction before recursively removing only the fixture.
+    fs.unlinkSync(modulesLink);
+    fs.rmSync(root, { recursive: true, force: true });
+  });
+
+  let stdout = "";
+  let stderr = "";
+  let answeredTitle = false;
+  let answeredAssets = false;
+  child.stdout.on("data", (chunk) => {
+    stdout += chunk;
+    if (!answeredTitle && stdout.includes("Skill title (default:")) {
+      answeredTitle = true;
+      child.stdin.write("\n");
+    }
+    if (!answeredAssets && stdout.includes("Would you like to add bundled assets?")) {
+      answeredAssets = true;
+      child.stdin.end("n\n");
+    }
+  });
+  child.stderr.on("data", (chunk) => {
+    stderr += chunk;
+  });
+  const exitCode = await new Promise((resolve, reject) => {
+    child.once("error", reject);
+    child.once("close", resolve);
+  });
+  assert.equal(exitCode, 0, `${stdout}\n${stderr}`);
+
+  const content = fs.readFileSync(
+    path.join(root, "skills", "yaml-roundtrip", "SKILL.md"),
+    "utf8"
+  );
+  const frontmatter = /^---\r?\n([\s\S]*?)\r?\n---(?:\r?\n|$)/.exec(content);
+  assert.ok(frontmatter, "generated skill must have YAML frontmatter");
+  return load(frontmatter[1]);
+}
+
+test(
+  "creates parseable frontmatter for descriptions containing a colon",
+  { timeout: 10000 },
+  async (t) => {
+    const description = "Review API: protobuf and gRPC contracts";
+    const metadata = await createSkill(t, description);
+
+    assert.equal(metadata.name, "yaml-roundtrip");
+    assert.equal(metadata.description, description);
+  }
+);
+
+test(
+  "preserves hashes, apostrophes, backslashes, and multiline descriptions",
+  { timeout: 10000 },
+  async (t) => {
+    for (const description of [
+      "Review developer's contracts # keep C:\\schemas\\protobuf intact",
+      "Review developer's API contracts\nKeep # details and C:\\schemas\\protobuf intact",
+    ]) {
+      const metadata = await createSkill(t, description);
+
+      assert.equal(metadata.description, description);
+    }
+  }
+);