fix(ce-compound): quote YAML array items starting with reserved indicators (#613)

Co-authored-by: Nathan Vale <hi@nathanvale.com>

tests/compound-support-files.test.ts

@@ -1,6 +1,7 @@
 import { readFile } from "fs/promises"
 import path from "path"
 import { describe, expect, test } from "bun:test"
+import { load } from "js-yaml"
 
 const PLUGIN_ROOT = path.join(process.cwd(), "plugins", "compound-engineering", "skills")
 
@@ -28,3 +29,86 @@ describe("ce-compound support file drift", () => {
     })
   }
 })
+
+/**
+ * Regression tests for the YAML-safety quoting rule for array items.
+ *
+ * Array items in frontmatter fields like `symptoms:` that start with a YAML
+ * reserved indicator (`, [, *, &, !, |, >, %, @, ?) or contain `: ` must be
+ * wrapped in double quotes — otherwise strict YAML parsers reject the file.
+ * See issue #606.
+ */
+describe("ce-compound YAML safety rule presence", () => {
+  for (const skill of SKILLS_WITH_COPIES) {
+    test(`${skill}/references/schema.yaml validation_rules includes YAML-safety entry`, async () => {
+      const raw = await readFile(
+        path.join(PLUGIN_ROOT, skill, "references/schema.yaml"),
+        "utf8",
+      )
+      const parsed = load(raw) as { validation_rules?: string[] } | null
+      expect(parsed).not.toBeNull()
+      expect(Array.isArray(parsed?.validation_rules)).toBe(true)
+      const hasSafetyRule = (parsed?.validation_rules ?? []).some((rule) =>
+        /array.*(quote|reserved indicator)|reserved indicator.*quote|YAML[- ]safety/i.test(rule),
+      )
+      expect(hasSafetyRule).toBe(true)
+    })
+
+    test(`${skill}/references/yaml-schema.md contains YAML Safety Rules section`, async () => {
+      const raw = await readFile(
+        path.join(PLUGIN_ROOT, skill, "references/yaml-schema.md"),
+        "utf8",
+      )
+      expect(/^##\s+YAML\s+Safety\s+Rules/mi.test(raw)).toBe(true)
+      // Concrete example stays present so the rule remains actionable.
+      expect(raw).toMatch(/"`sudo dscacheutil/)
+    })
+
+    test(`${skill}/assets/resolution-template.md references YAML safety rules`, async () => {
+      const raw = await readFile(
+        path.join(PLUGIN_ROOT, skill, "assets/resolution-template.md"),
+        "utf8",
+      )
+      expect(/YAML[- ]safety/i.test(raw)).toBe(true)
+      expect(raw).toMatch(/yaml-schema\.md/)
+    })
+  }
+
+  test("ce-compound/SKILL.md points at YAML Safety Rules in both frontmatter-writing spots", async () => {
+    const raw = await readFile(
+      path.join(PLUGIN_ROOT, "ce-compound", "SKILL.md"),
+      "utf8",
+    )
+    // Match the distinctive write-path pointer phrase, not generic yaml-schema.md
+    // references (which also appear in the support-files list and inputs section).
+    // Both Full-mode Phase 2 step 5 and Lightweight mode step 3 must carry the
+    // pointer so dropping either one is caught.
+    const pointer = /YAML[- ]safety\s+quoting\s+rule\s+for\s+array\s+items/gi
+    const pointerMatches = raw.match(pointer) ?? []
+    expect(pointerMatches.length).toBeGreaterThanOrEqual(2)
+
+    // Each pointer must sit in the frontmatter-write step (step 5 of Full mode,
+    // step 3 of Lightweight mode), not drift to an unrelated location. Both
+    // steps carry the "YAML frontmatter" phrase adjacent to the pointer.
+    const frontmatterAdjacent = raw.match(
+      /YAML\s+frontmatter[\s\S]{0,400}?YAML[- ]safety\s+quoting\s+rule\s+for\s+array\s+items/gi,
+    ) ?? []
+    expect(frontmatterAdjacent.length).toBeGreaterThanOrEqual(2)
+  })
+
+  test("ce-compound-refresh/SKILL.md points at YAML-safety rules in the Replace flow", async () => {
+    const raw = await readFile(
+      path.join(PLUGIN_ROOT, "ce-compound-refresh", "SKILL.md"),
+      "utf8",
+    )
+    // Anchor to the Replace Flow section so a drifted or deleted pointer is
+    // caught even if the phrase still appears elsewhere in the file.
+    const replaceFlowMatch = raw.match(
+      /###\s+Replace\s+Flow\b([\s\S]*?)(?=\n###\s+\w|\n##\s+\w|$)/,
+    )
+    expect(replaceFlowMatch).not.toBeNull()
+    const replaceFlow = replaceFlowMatch?.[1] ?? ""
+    expect(/YAML[- ]safety/i.test(replaceFlow)).toBe(true)
+    expect(replaceFlow).toMatch(/yaml-schema\.md/)
+  })
+})