Detect skill install failures and surface them as agent failure context; fix needex/skills fallback crash (#42642)

* Add skill install failure detection and fix needex/skills fallback

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* Address code review feedback on skill install failure detection

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* Harden skill install failure serialization and reporting

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* Tighten failure record validation and compatibility parsing

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>
Co-authored-by: Peli de Halleux <pelikhan@users.noreply.github.com>

Author: Copilot

.github/workflows/impeccable-skills-reviewer.lock.yml

@@ -2,7 +2,7 @@
 private: true
 emoji: "🧵"
 name: "Impeccable Skills Reviewer"
-description: Reviews pull requests using Impeccable skills from needex/skills and applies the most relevant skills based on changed files
+description: Reviews pull requests using Impeccable skills and applies the most relevant skills based on changed files
 on:
   pull_request:
     types: [ready_for_review]
@@ -12,7 +12,7 @@ permissions:
   pull-requests: read
   copilot-requests: write
 skills:
-  - skill: ${{ vars.IMPECCABLE_SKILLS_REF || 'needex/skills' }}
+  - skill: ${{ vars.IMPECCABLE_SKILLS_REF }}
     github-token: ${{ secrets.GITHUB_TOKEN }}
 
 sandbox:
@@ -77,7 +77,7 @@ timeout-minutes: 15
 
 # Impeccable Skills Reviewer
 
-You are a pull request reviewer that uses Impeccable skills from `needex/skills`.
+You are a pull request reviewer that uses Impeccable skills.
 
 ## Mission
 

.github/workflows/impeccable-skills-reviewer.md

@@ -0,0 +1,46 @@
+// @ts-check
+/// <reference types="@actions/github-script" />
+
+const fs = require("fs");
+
+/** Path written by install_frontmatter_skills.cjs during the activation job. */
+const SKILL_FAILURES_FILE = "/tmp/gh-aw/skill_install_failures.json";
+
+/**
+ * Read the shared failures file produced by install_frontmatter_skills.cjs.
+ * Returns an empty array when the file does not exist or cannot be parsed.
+ * @returns {Array<{skill: string; error: string}>}
+ */
+function readSkillInstallFailures() {
+  try {
+    if (!fs.existsSync(SKILL_FAILURES_FILE)) {
+      return [];
+    }
+    const raw = fs.readFileSync(SKILL_FAILURES_FILE, "utf8");
+    const parsed = JSON.parse(raw);
+    if (!Array.isArray(parsed)) {
+      return [];
+    }
+    return parsed.filter(entry => entry && typeof entry.skill === "string" && typeof entry.error === "string");
+  } catch (readErr) {
+    // Warn so "no failures" vs "couldn't read failures file" is distinguishable in logs
+    core.warning(`Could not read skill install failures file: ${readErr instanceof Error ? readErr.message : String(readErr)}`);
+    return [];
+  }
+}
+
+async function main() {
+  const failures = readSkillInstallFailures();
+  const failureCount = failures.length;
+
+  core.info(`Skill install failures detected: ${failureCount}`);
+
+  core.setOutput("failure_count", String(failureCount));
+  core.setOutput("errors", failures.map(f => `${f.skill}\t${f.error.replace(/\r?\n/g, " ").replace(/\t/g, " ")}`).join("\n"));
+
+  if (failureCount > 0) {
+    core.warning(`${failureCount} skill(s) failed to install — see agent failure issue/comment for details`);
+  }
+}
+
+module.exports = { main, readSkillInstallFailures };

.github/workflows/mattpocock-skills-reviewer.lock.yml

@@ -0,0 +1,46 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import fs from "fs";
+import { createRequire } from "module";
+
+const require = createRequire(import.meta.url);
+const script = require("./collect_skill_install_failures.cjs");
+
+describe("collect_skill_install_failures", () => {
+  let originalCore;
+
+  beforeEach(() => {
+    originalCore = global.core;
+    global.core = {
+      info: vi.fn(),
+      warning: vi.fn(),
+      setOutput: vi.fn(),
+    };
+  });
+
+  afterEach(() => {
+    global.core = originalCore;
+    fs.rmSync("/tmp/gh-aw/skill_install_failures.json", { force: true });
+  });
+
+  it("returns empty array when failures file is missing", () => {
+    expect(script.readSkillInstallFailures()).toEqual([]);
+  });
+
+  it("filters malformed entries and emits sanitized outputs", async () => {
+    fs.mkdirSync("/tmp/gh-aw", { recursive: true });
+    fs.writeFileSync("/tmp/gh-aw/skill_install_failures.json", JSON.stringify([{ skill: "owner/repo", error: "line1\nline2" }, { skill: "missing-error" }]), "utf8");
+
+    await script.main();
+
+    expect(global.core.setOutput).toHaveBeenCalledWith("failure_count", "1");
+    expect(global.core.setOutput).toHaveBeenCalledWith("errors", "owner/repo\tline1 line2");
+  });
+
+  it("warns and returns empty array on unreadable failures file", () => {
+    fs.mkdirSync("/tmp/gh-aw", { recursive: true });
+    fs.writeFileSync("/tmp/gh-aw/skill_install_failures.json", "{invalid", "utf8");
+
+    expect(script.readSkillInstallFailures()).toEqual([]);
+    expect(global.core.warning).toHaveBeenCalledWith(expect.stringContaining("Could not read skill install failures file"));
+  });
+});