refactor: reuse shared skills prompt formatter

src/skills/loading/session.ts

@@ -7,6 +7,7 @@ import type { ResourceDiagnostic } from "../../agents/sessions/diagnostics.js";
 import { createSyntheticSourceInfo, type SourceInfo } from "../../agents/sessions/source-info.js";
 import { parseFrontmatter } from "../../agents/utils/frontmatter.js";
 import { canonicalizePath } from "../../agents/utils/paths.js";
+import { formatSkillsForPrompt as formatSkillContractForPrompt } from "./skill-contract.js";
 
 /** Max name length per spec */
 const MAX_NAME_LENGTH = 64;
@@ -343,39 +344,7 @@ function loadSkillFromFile(
  */
 export function formatSkillsForPrompt(skills: Skill[]): string {
   const visibleSkills = skills.filter((s) => !s.disableModelInvocation);
-
-  if (visibleSkills.length === 0) {
-    return "";
-  }
-
-  const lines = [
-    "\n\nThe following skills provide specialized instructions for specific tasks.",
-    "Use the read tool to load a skill's file when the task matches its description.",
-    "When a skill file references a relative path, resolve it against the skill directory (parent of SKILL.md / dirname of the path) and use that absolute path in tool commands.",
-    "",
-    "<available_skills>",
-  ];
-
-  for (const skill of visibleSkills) {
-    lines.push("  <skill>");
-    lines.push(`    <name>${escapeXml(skill.name)}</name>`);
-    lines.push(`    <description>${escapeXml(skill.description)}</description>`);
-    lines.push(`    <location>${escapeXml(skill.filePath)}</location>`);
-    lines.push("  </skill>");
-  }
-
-  lines.push("</available_skills>");
-
-  return lines.join("\n");
-}
-
-function escapeXml(str: string): string {
-  return str
-    .replace(/&/g, "&amp;")
-    .replace(/</g, "&lt;")
-    .replace(/>/g, "&gt;")
-    .replace(/"/g, "&quot;")
-    .replace(/'/g, "&apos;");
+  return formatSkillContractForPrompt(visibleSkills);
 }
 
 export interface LoadSkillsOptions {