refactor(prompt): dedupe repeated skill guidance blocks

src/agents/atlas/prompt-section-builder.ts

@@ -6,7 +6,7 @@
  */
 
 import type { CategoryConfig } from "../../config/schema"
-import { formatCustomSkillsBlock, type AvailableAgent, type AvailableSkill } from "../dynamic-agent-prompt-builder"
+import type { AvailableAgent, AvailableSkill } from "../dynamic-agent-prompt-builder"
 import { CATEGORY_DESCRIPTIONS } from "../../tools/delegate-task/constants"
 import { mergeCategories } from "../../shared/merge-categories"
 import { truncateDescription } from "../../shared/truncate-description"
@@ -58,43 +58,16 @@ export function buildSkillsSection(skills: AvailableSkill[]): string {
   const builtinSkills = skills.filter((s) => s.location === "plugin")
   const customSkills = skills.filter((s) => s.location !== "plugin")
 
-   const builtinRows = builtinSkills.map((s) => {
-     const shortDesc = truncateDescription(s.description)
-     return `- **\`${s.name}\`** — ${shortDesc}`
-   })
-
-   const customRows = customSkills.map((s) => {
-     const shortDesc = truncateDescription(s.description)
-     const source = s.location === "project" ? "project" : "user"
-     return `- **\`${s.name}\`** (${source}): ${shortDesc}`
-   })
-
-  const customSkillBlock = formatCustomSkillsBlock(customRows, customSkills, "**")
-
-  let skillsTable: string
-
-  if (customSkills.length > 0 && builtinSkills.length > 0) {
-    skillsTable = `**Built-in Skills:**
-
-${builtinRows.join("\n")}
-
-${customSkillBlock}`
-  } else if (customSkills.length > 0) {
-    skillsTable = customSkillBlock
-  } else {
-    skillsTable = `${builtinRows.join("\n")}`
-  }
-
   return `
 #### 3.2.2: Skill Selection (PREPEND TO PROMPT)
 
-**Skills are specialized instructions that guide subagent behavior. Consider them alongside category selection.**
-
-${skillsTable}
+**Use the \`Category + Skills Delegation System\` section below as the single source of truth for skill details.**
+- Built-in skills available: ${builtinSkills.length}
+- User-installed skills available: ${customSkills.length}
 
 **MANDATORY: Evaluate ALL skills (built-in AND user-installed) for relevance to your task.**
 
-Read each skill's description and ask: "Does this skill's domain overlap with my task?"
+Read each skill's description in the section below and ask: "Does this skill's domain overlap with my task?"
 - If YES: INCLUDE in load_skills=[...]
 - If NO: You MUST justify why in your pre-delegation declaration
 

src/agents/dynamic-agent-prompt-builder.test.ts

@@ -43,16 +43,16 @@ describe("buildCategorySkillsDelegationGuide", () => {
     expect(result).toContain("HIGH PRIORITY")
   })
 
-  it("should include custom skill names in CRITICAL warning", () => {
+  it("should list custom skills and keep CRITICAL warning", () => {
     //#given: custom skills installed
     const allSkills = [...builtinSkills, ...customUserSkills]
 
     //#when: building the delegation guide
     const result = buildCategorySkillsDelegationGuide(categories, allSkills)
 
-    //#then: should mention custom skills by name in the warning
-    expect(result).toContain('"react-19"')
-    expect(result).toContain('"tailwind-4"')
+    //#then: should mention custom skills by name and include warning
+    expect(result).toContain("`react-19`")
+    expect(result).toContain("`tailwind-4`")
     expect(result).toContain("CRITICAL")
   })
 
@@ -180,8 +180,8 @@ describe("formatCustomSkillsBlock", () => {
     //#then: contains all expected elements
     expect(result).toContain("User-Installed Skills (HIGH PRIORITY)")
     expect(result).toContain("CRITICAL")
-    expect(result).toContain('"react-19"')
-    expect(result).toContain('"tailwind-4"')
+    expect(result).toContain("`react-19`")
+    expect(result).toContain("`tailwind-4`")
     expect(result).toContain("| user |")
     expect(result).toContain("| project |")
   })

src/agents/dynamic-agent-prompt-builder.ts

@@ -167,7 +167,6 @@ export function formatCustomSkillsBlock(
   customSkills: AvailableSkill[],
   headerLevel: "####" | "**" = "####"
 ): string {
-  const customSkillNames = customSkills.map((s) => `"${s.name}"`).join(", ")
   const header = headerLevel === "####"
     ? `#### User-Installed Skills (HIGH PRIORITY)`
     : `**User-Installed Skills (HIGH PRIORITY):**`
@@ -180,7 +179,7 @@ Subagents are STATELESS — they lose all custom knowledge unless you pass these
 ${customRows.join("\n")}
 
 > **CRITICAL**: Ignoring user-installed skills when they match the task domain is a failure.
-> The user installed ${customSkillNames} for a reason — USE THEM when the task overlaps with their domain.`
+> The user installed custom skills for a reason — USE THEM when the task overlaps with their domain.`
 }
 
 export function buildCategorySkillsDelegationGuide(categories: AvailableCategory[], skills: AvailableSkill[]): string {