From a52595fdbce684ee9d46c1b0adc210431e96eced Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:20:27 -0400
Subject: [PATCH 01/15] feat: add copilot host support to gen-skill-docs

Add 'copilot' as a recognized host type alongside 'claude' and 'codex'.
Copilot uses the same .agents/skills/ output directory and dynamic
GSTACK_ROOT preamble pattern as codex, with ~/.copilot/skills/gstack
as the default global path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 scripts/gen-skill-docs.ts | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/scripts/gen-skill-docs.ts b/scripts/gen-skill-docs.ts
index 340dbb3ca..6a57ac641 100644
--- a/scripts/gen-skill-docs.ts
+++ b/scripts/gen-skill-docs.ts
@@ -19,7 +19,7 @@ const DRY_RUN = process.argv.includes('--dry-run');
 
 // ─── Template Context ───────────────────────────────────────
 
-type Host = 'claude' | 'codex';
+type Host = 'claude' | 'codex' | 'copilot';
 const OPENAI_SHORT_DESCRIPTION_LIMIT = 120;
 
 const HOST_ARG = process.argv.find(a => a.startsWith('--host'));
@@ -27,8 +27,9 @@ const HOST: Host = (() => {
   if (!HOST_ARG) return 'claude';
   const val = HOST_ARG.includes('=') ? HOST_ARG.split('=')[1] : process.argv[process.argv.indexOf(HOST_ARG) + 1];
   if (val === 'codex' || val === 'agents') return 'codex';
+  if (val === 'copilot') return 'copilot';
   if (val === 'claude') return 'claude';
-  throw new Error(`Unknown host: ${val}. Use claude, codex, or agents.`);
+  throw new Error(`Unknown host: ${val}. Use claude, codex, copilot, or agents.`);
 })();
 
 interface HostPaths {
@@ -51,6 +52,12 @@ const HOST_PATHS: Record<Host, HostPaths> = {
     binDir: '$GSTACK_BIN',
     browseDir: '$GSTACK_BROWSE',
   },
+  copilot: {
+    skillRoot: '$GSTACK_ROOT',
+    localSkillRoot: '.agents/skills/gstack',
+    binDir: '$GSTACK_BIN',
+    browseDir: '$GSTACK_BROWSE',
+  },
 };
 
 interface TemplateContext {
@@ -183,6 +190,13 @@ GSTACK_ROOT="$HOME/.codex/skills/gstack"
 [ -n "$_ROOT" ] && [ -d "$_ROOT/.agents/skills/gstack" ] && GSTACK_ROOT="$_ROOT/.agents/skills/gstack"
 GSTACK_BIN="$GSTACK_ROOT/bin"
 GSTACK_BROWSE="$GSTACK_ROOT/browse/dist"
+`
+    : ctx.host === 'copilot'
+    ? `_ROOT=$(git rev-parse --show-toplevel 2>/dev/null)
+GSTACK_ROOT="$HOME/.copilot/skills/gstack"
+[ -n "$_ROOT" ] && [ -d "$_ROOT/.agents/skills/gstack" ] && GSTACK_ROOT="$_ROOT/.agents/skills/gstack"
+GSTACK_BIN="$GSTACK_ROOT/bin"
+GSTACK_BROWSE="$GSTACK_ROOT/browse/dist"
 `
     : '';
 
@@ -2969,8 +2983,8 @@ function processTemplate(tmplPath: string, host: Host = 'claude'): { outputPath:
   // Determine skill directory relative to ROOT
   const skillDir = path.relative(ROOT, path.dirname(tmplPath));
 
-  // For codex host, route output to .agents/skills/{codexSkillName}/SKILL.md
-  if (host === 'codex') {
+  // For codex/copilot host, route output to .agents/skills/{codexSkillName}/SKILL.md
+  if (host === 'codex' || host === 'copilot') {
     const codexName = codexSkillName(skillDir === '.' ? '' : skillDir);
     outputDir = path.join(ROOT, '.agents', 'skills', codexName);
     fs.mkdirSync(outputDir, { recursive: true });
@@ -3002,8 +3016,8 @@ function processTemplate(tmplPath: string, host: Host = 'claude'): { outputPath:
     throw new Error(`Unresolved placeholders in ${relTmplPath}: ${remaining.join(', ')}`);
   }
 
-  // For codex host: transform frontmatter and replace Claude-specific paths
-  if (host === 'codex') {
+  // For codex/copilot host: transform frontmatter and replace Claude-specific paths
+  if (host === 'codex' || host === 'copilot') {
     // Extract hook safety prose BEFORE transforming frontmatter (which strips hooks)
     const safetyProse = extractHookSafetyProse(tmplContent);
 
@@ -3063,8 +3077,8 @@ function findTemplates(): string[] {
 let hasChanges = false;
 
 for (const tmplPath of findTemplates()) {
-  // Skip /codex skill for codex host (self-referential — it's a Claude wrapper around codex exec)
-  if (HOST === 'codex') {
+  // Skip /codex skill for codex/copilot host (self-referential — it's a Claude wrapper around codex exec)
+  if (HOST === 'codex' || HOST === 'copilot') {
     const dir = path.basename(path.dirname(tmplPath));
     if (dir === 'codex') continue;
   }

From 4bf114c98190a8d8bec991e4123d330d69d9fcfa Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:21:39 -0400
Subject: [PATCH 02/15] feat: add --host copilot to setup script

Add copilot as a recognized host alongside claude, codex, and kiro.
Auto-detection checks for 'gh copilot --version'. Global install
goes to ~/.copilot/skills/gstack following the same pattern as kiro.
Copies .agents/skills/ output and rewrites paths for copilot.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 setup | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 71 insertions(+), 10 deletions(-)

diff --git a/setup b/setup
index 4d7d29c01..544cae3d0 100755
--- a/setup
+++ b/setup
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# gstack setup — build browser binary + register skills with Claude Code / Codex
+# gstack setup — build browser binary + register skills with Claude Code / Codex / Copilot
 set -e
 
 if ! command -v bun >/dev/null 2>&1; then
@@ -14,6 +14,8 @@ INSTALL_SKILLS_DIR="$(dirname "$INSTALL_GSTACK_DIR")"
 BROWSE_BIN="$SOURCE_GSTACK_DIR/browse/dist/browse"
 CODEX_SKILLS="$HOME/.codex/skills"
 CODEX_GSTACK="$CODEX_SKILLS/gstack"
+COPILOT_SKILLS="$HOME/.copilot/skills"
+COPILOT_GSTACK="$COPILOT_SKILLS/gstack"
 
 IS_WINDOWS=0
 case "$(uname -s)" in
@@ -24,33 +26,37 @@ esac
 HOST="claude"
 while [ $# -gt 0 ]; do
   case "$1" in
-    --host) [ -z "$2" ] && echo "Missing value for --host (expected claude, codex, kiro, or auto)" >&2 && exit 1; HOST="$2"; shift 2 ;;
+    --host) [ -z "$2" ] && echo "Missing value for --host (expected claude, codex, copilot, kiro, or auto)" >&2 && exit 1; HOST="$2"; shift 2 ;;
     --host=*) HOST="${1#--host=}"; shift ;;
     *) shift ;;
   esac
 done
 
 case "$HOST" in
-  claude|codex|kiro|auto) ;;
-  *) echo "Unknown --host value: $HOST (expected claude, codex, kiro, or auto)" >&2; exit 1 ;;
+  claude|codex|copilot|kiro|auto) ;;
+  *) echo "Unknown --host value: $HOST (expected claude, codex, copilot, kiro, or auto)" >&2; exit 1 ;;
 esac
 
 # For auto: detect which agents are installed
 INSTALL_CLAUDE=0
 INSTALL_CODEX=0
+INSTALL_COPILOT=0
 INSTALL_KIRO=0
 if [ "$HOST" = "auto" ]; then
   command -v claude >/dev/null 2>&1 && INSTALL_CLAUDE=1
   command -v codex >/dev/null 2>&1 && INSTALL_CODEX=1
+  command -v gh >/dev/null 2>&1 && gh copilot --version >/dev/null 2>&1 && INSTALL_COPILOT=1
   command -v kiro-cli >/dev/null 2>&1 && INSTALL_KIRO=1
   # If none found, default to claude
-  if [ "$INSTALL_CLAUDE" -eq 0 ] && [ "$INSTALL_CODEX" -eq 0 ] && [ "$INSTALL_KIRO" -eq 0 ]; then
+  if [ "$INSTALL_CLAUDE" -eq 0 ] && [ "$INSTALL_CODEX" -eq 0 ] && [ "$INSTALL_COPILOT" -eq 0 ] && [ "$INSTALL_KIRO" -eq 0 ]; then
     INSTALL_CLAUDE=1
   fi
 elif [ "$HOST" = "claude" ]; then
   INSTALL_CLAUDE=1
 elif [ "$HOST" = "codex" ]; then
   INSTALL_CODEX=1
+elif [ "$HOST" = "copilot" ]; then
+  INSTALL_COPILOT=1
 elif [ "$HOST" = "kiro" ]; then
   INSTALL_KIRO=1
 fi
@@ -128,11 +134,12 @@ if [ ! -x "$BROWSE_BIN" ]; then
   exit 1
 fi
 
-# 1b. Generate .agents/ Codex skill docs — always regenerate to prevent stale descriptions.
+# 1b. Generate .agents/ skill docs — always regenerate to prevent stale descriptions.
 # .agents/ is no longer committed — generated at setup time from .tmpl templates.
 # bun run build already does this, but we need it when NEEDS_BUILD=0 (binary is fresh).
 # Always regenerate: generation is fast (<2s) and mtime-based staleness checks are fragile
 # (miss stale files when timestamps match after clone/checkout/upgrade).
+# Codex and Copilot both use .agents/skills/ — generate once with --host codex.
 AGENTS_DIR="$SOURCE_GSTACK_DIR/.agents/skills"
 NEEDS_AGENTS_GEN=1
 
@@ -421,14 +428,68 @@ if [ "$INSTALL_KIRO" -eq 1 ]; then
   fi
 fi
 
-# 7. Create .agents/ sidecar symlinks for the real Codex skill target.
-# The root Codex skill ends up pointing at $SOURCE_GSTACK_DIR/.agents/skills/gstack,
+# 7. Install for Copilot CLI (copy from .agents/skills, rewrite paths)
+if [ "$INSTALL_COPILOT" -eq 1 ]; then
+  AGENTS_DIR="$SOURCE_GSTACK_DIR/.agents/skills"
+  mkdir -p "$COPILOT_SKILLS"
+
+  # Create gstack dir with symlinks for runtime assets, copy+sed for SKILL.md
+  # Remove old whole-dir symlink from previous installs
+  [ -L "$COPILOT_GSTACK" ] && rm -f "$COPILOT_GSTACK"
+  mkdir -p "$COPILOT_GSTACK" "$COPILOT_GSTACK/browse" "$COPILOT_GSTACK/gstack-upgrade" "$COPILOT_GSTACK/review"
+  ln -snf "$SOURCE_GSTACK_DIR/bin" "$COPILOT_GSTACK/bin"
+  ln -snf "$SOURCE_GSTACK_DIR/browse/dist" "$COPILOT_GSTACK/browse/dist"
+  ln -snf "$SOURCE_GSTACK_DIR/browse/bin" "$COPILOT_GSTACK/browse/bin"
+  # ETHOS.md — referenced by "Search Before Building" in all skill preambles
+  if [ -f "$SOURCE_GSTACK_DIR/ETHOS.md" ]; then
+    ln -snf "$SOURCE_GSTACK_DIR/ETHOS.md" "$COPILOT_GSTACK/ETHOS.md"
+  fi
+  # gstack-upgrade skill
+  if [ -f "$AGENTS_DIR/gstack-upgrade/SKILL.md" ]; then
+    ln -snf "$AGENTS_DIR/gstack-upgrade/SKILL.md" "$COPILOT_GSTACK/gstack-upgrade/SKILL.md"
+  fi
+  # Review runtime assets (individual files, not whole dir)
+  for f in checklist.md design-checklist.md greptile-triage.md TODOS-format.md; do
+    if [ -f "$SOURCE_GSTACK_DIR/review/$f" ]; then
+      ln -snf "$SOURCE_GSTACK_DIR/review/$f" "$COPILOT_GSTACK/review/$f"
+    fi
+  done
+
+  # Rewrite root SKILL.md paths for Copilot
+  sed -e "s|~/.claude/skills/gstack|~/.copilot/skills/gstack|g" \
+      -e "s|\.claude/skills/gstack|.copilot/skills/gstack|g" \
+      -e "s|\.claude/skills|.copilot/skills|g" \
+      "$SOURCE_GSTACK_DIR/SKILL.md" > "$COPILOT_GSTACK/SKILL.md"
+
+  if [ ! -d "$AGENTS_DIR" ]; then
+    echo "  warning: no .agents/skills/ directory found — run 'bun run build' first" >&2
+  else
+    for skill_dir in "$AGENTS_DIR"/gstack*/; do
+      [ -f "$skill_dir/SKILL.md" ] || continue
+      skill_name="$(basename "$skill_dir")"
+      target_dir="$COPILOT_SKILLS/$skill_name"
+      mkdir -p "$target_dir"
+      # Generated Codex skills use $HOME/.codex (not ~/), plus $GSTACK_ROOT variables.
+      # Rewrite the default GSTACK_ROOT value and any remaining literal paths.
+      sed -e 's|\$HOME/.codex/skills/gstack|$HOME/.copilot/skills/gstack|g' \
+          -e "s|~/.codex/skills/gstack|~/.copilot/skills/gstack|g" \
+          -e "s|~/.claude/skills/gstack|~/.copilot/skills/gstack|g" \
+          "$skill_dir/SKILL.md" > "$target_dir/SKILL.md"
+    done
+    echo "gstack ready (copilot)."
+    echo "  browse: $BROWSE_BIN"
+    echo "  copilot skills: $COPILOT_SKILLS"
+  fi
+fi
+
+# 8. Create .agents/ sidecar symlinks for the real Codex/Copilot skill target.
+# The root Codex/Copilot skill ends up pointing at $SOURCE_GSTACK_DIR/.agents/skills/gstack,
 # so the runtime assets must live there for both global and repo-local installs.
-if [ "$INSTALL_CODEX" -eq 1 ]; then
+if [ "$INSTALL_CODEX" -eq 1 ] || [ "$INSTALL_COPILOT" -eq 1 ]; then
   create_agents_sidecar "$SOURCE_GSTACK_DIR"
 fi
 
-# 8. First-time welcome + legacy cleanup
+# 9. First-time welcome + legacy cleanup
 if [ ! -d "$HOME/.gstack" ]; then
   mkdir -p "$HOME/.gstack"
   echo "  Welcome! Run /gstack-upgrade anytime to stay current."

From 944fd3cc688f2ff8ef4bb31230f54b7583ab590b Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:23:13 -0400
Subject: [PATCH 03/15] feat: add Copilot CLI session scanning to global
 discover

Add 'copilot' as a tool type alongside claude_code, codex, and gemini.
Scans ~/.config/gh-copilot/ for conversation logs. Includes copilot
in all session counts, repo aggregations, and summary output.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 bin/gstack-global-discover.ts | 73 +++++++++++++++++++++++++++++------
 1 file changed, 62 insertions(+), 11 deletions(-)

diff --git a/bin/gstack-global-discover.ts b/bin/gstack-global-discover.ts
index e6c64f561..810d41d6a 100644
--- a/bin/gstack-global-discover.ts
+++ b/bin/gstack-global-discover.ts
@@ -1,6 +1,6 @@
 #!/usr/bin/env bun
 /**
- * gstack-global-discover — Discover AI coding sessions across Claude Code, Codex CLI, and Gemini CLI.
+ * gstack-global-discover — Discover AI coding sessions across Claude Code, Codex CLI, Gemini CLI, and Copilot CLI.
  * Resolves each session's working directory to a git repo, deduplicates by normalized remote URL,
  * and outputs structured JSON to stdout.
  *
@@ -17,7 +17,7 @@ import { homedir } from "os";
 // ── Types ──────────────────────────────────────────────────────────────────
 
 interface Session {
-  tool: "claude_code" | "codex" | "gemini";
+  tool: "claude_code" | "codex" | "gemini" | "copilot";
   cwd: string;
 }
 
@@ -25,7 +25,7 @@ interface Repo {
   name: string;
   remote: string;
   paths: string[];
-  sessions: { claude_code: number; codex: number; gemini: number };
+  sessions: { claude_code: number; codex: number; gemini: number; copilot: number };
 }
 
 interface DiscoveryResult {
@@ -36,6 +36,7 @@ interface DiscoveryResult {
     claude_code: { total_sessions: number; repos: number };
     codex: { total_sessions: number; repos: number };
     gemini: { total_sessions: number; repos: number };
+    copilot: { total_sessions: number; repos: number };
   };
   total_sessions: number;
   total_repos: number;
@@ -440,7 +441,53 @@ function scanGemini(since: Date): Session[] {
   return sessions;
 }
 
-// ── Deduplication ──────────────────────────────────────────────────────────
+function scanCopilot(since: Date): Session[] {
+  // GitHub Copilot CLI stores conversation history in ~/.config/gh-copilot/
+  const configDir = join(homedir(), ".config", "gh-copilot");
+  if (!existsSync(configDir)) return [];
+
+  const sessions: Session[] = [];
+
+  // Scan for conversation log files
+  try {
+    const entries = readdirSync(configDir);
+    for (const entry of entries) {
+      const filePath = join(configDir, entry);
+      try {
+        const stat = statSync(filePath);
+        if (!stat.isFile() || stat.mtime < since) continue;
+        if (!entry.endsWith(".json") && !entry.endsWith(".jsonl")) continue;
+
+        // Try to extract cwd from the conversation file
+        const fd = openSync(filePath, "r");
+        const buf = Buffer.alloc(4096);
+        const bytesRead = readSync(fd, buf, 0, 4096, 0);
+        closeSync(fd);
+        const text = buf.toString("utf-8", 0, bytesRead);
+
+        // Look for cwd in JSON metadata
+        for (const line of text.split("\n").slice(0, 15)) {
+          if (!line.trim()) continue;
+          try {
+            const obj = JSON.parse(line);
+            if (obj.cwd && existsSync(obj.cwd)) {
+              sessions.push({ tool: "copilot", cwd: obj.cwd });
+              break;
+            }
+          } catch {
+            continue;
+          }
+        }
+      } catch {
+        continue;
+      }
+    }
+  } catch {
+    // Directory read error
+  }
+
+  return sessions;
+}
 
 async function resolveAndDeduplicate(sessions: Session[]): Promise<Repo[]> {
   // Group sessions by cwd
@@ -496,7 +543,7 @@ async function resolveAndDeduplicate(sessions: Session[]): Promise<Repo[]> {
       }
     }
 
-    const sessionCounts = { claude_code: 0, codex: 0, gemini: 0 };
+    const sessionCounts = { claude_code: 0, codex: 0, gemini: 0, copilot: 0 };
     for (const s of data.sessions) {
       sessionCounts[s.tool]++;
     }
@@ -512,8 +559,8 @@ async function resolveAndDeduplicate(sessions: Session[]): Promise<Repo[]> {
   // Sort by total sessions descending
   repos.sort(
     (a, b) =>
-      b.sessions.claude_code + b.sessions.codex + b.sessions.gemini -
-      (a.sessions.claude_code + a.sessions.codex + a.sessions.gemini)
+      b.sessions.claude_code + b.sessions.codex + b.sessions.gemini + b.sessions.copilot -
+      (a.sessions.claude_code + a.sessions.codex + a.sessions.gemini + a.sessions.copilot)
   );
 
   return repos;
@@ -530,12 +577,13 @@ async function main() {
   const ccSessions = scanClaudeCode(sinceDate);
   const codexSessions = scanCodex(sinceDate);
   const geminiSessions = scanGemini(sinceDate);
+  const copilotSessions = scanCopilot(sinceDate);
 
-  const allSessions = [...ccSessions, ...codexSessions, ...geminiSessions];
+  const allSessions = [...ccSessions, ...codexSessions, ...geminiSessions, ...copilotSessions];
 
   // Summary to stderr
   console.error(
-    `Discovered: ${ccSessions.length} CC sessions, ${codexSessions.length} Codex sessions, ${geminiSessions.length} Gemini sessions`
+    `Discovered: ${ccSessions.length} CC sessions, ${codexSessions.length} Codex sessions, ${geminiSessions.length} Gemini sessions, ${copilotSessions.length} Copilot sessions`
   );
 
   // Deduplicate
@@ -547,6 +595,7 @@ async function main() {
   const ccRepos = new Set(repos.filter((r) => r.sessions.claude_code > 0).map((r) => r.remote)).size;
   const codexRepos = new Set(repos.filter((r) => r.sessions.codex > 0).map((r) => r.remote)).size;
   const geminiRepos = new Set(repos.filter((r) => r.sessions.gemini > 0).map((r) => r.remote)).size;
+  const copilotRepos = new Set(repos.filter((r) => r.sessions.copilot > 0).map((r) => r.remote)).size;
 
   const result: DiscoveryResult = {
     window: since,
@@ -556,6 +605,7 @@ async function main() {
       claude_code: { total_sessions: ccSessions.length, repos: ccRepos },
       codex: { total_sessions: codexSessions.length, repos: codexRepos },
       gemini: { total_sessions: geminiSessions.length, repos: geminiRepos },
+      copilot: { total_sessions: copilotSessions.length, repos: copilotRepos },
     },
     total_sessions: allSessions.length,
     total_repos: repos.length,
@@ -566,15 +616,16 @@ async function main() {
   } else {
     // Summary format
     console.log(`Window: ${since} (since ${startDate})`);
-    console.log(`Sessions: ${allSessions.length} total (CC: ${ccSessions.length}, Codex: ${codexSessions.length}, Gemini: ${geminiSessions.length})`);
+    console.log(`Sessions: ${allSessions.length} total (CC: ${ccSessions.length}, Codex: ${codexSessions.length}, Gemini: ${geminiSessions.length}, Copilot: ${copilotSessions.length})`);
     console.log(`Repos: ${repos.length} unique`);
     console.log("");
     for (const repo of repos) {
-      const total = repo.sessions.claude_code + repo.sessions.codex + repo.sessions.gemini;
+      const total = repo.sessions.claude_code + repo.sessions.codex + repo.sessions.gemini + repo.sessions.copilot;
       const tools = [];
       if (repo.sessions.claude_code > 0) tools.push(`CC:${repo.sessions.claude_code}`);
       if (repo.sessions.codex > 0) tools.push(`Codex:${repo.sessions.codex}`);
       if (repo.sessions.gemini > 0) tools.push(`Gemini:${repo.sessions.gemini}`);
+      if (repo.sessions.copilot > 0) tools.push(`Copilot:${repo.sessions.copilot}`);
       console.log(`  ${repo.name} (${total} sessions) — ${tools.join(", ")}`);
       console.log(`    Remote: ${repo.remote}`);
       console.log(`    Paths: ${repo.paths.join(", ")}`);

From 3d8b839192f9d1066b1279023e3b70342a88fe75 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:23:33 -0400
Subject: [PATCH 04/15] feat: add Copilot freshness check to skill:check

Add a Copilot freshness section alongside the existing Codex check.
Runs gen-skill-docs with --host copilot --dry-run to verify generated
files are up to date.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 scripts/skill-check.ts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/scripts/skill-check.ts b/scripts/skill-check.ts
index 59f306c2c..358a18f46 100644
--- a/scripts/skill-check.ts
+++ b/scripts/skill-check.ts
@@ -163,5 +163,19 @@ try {
   console.log('      Run: bun run gen:skill-docs --host codex');
 }
 
+console.log('\n  Freshness (Copilot):');
+try {
+  execSync('bun run scripts/gen-skill-docs.ts --host copilot --dry-run', { cwd: ROOT, stdio: 'pipe' });
+  console.log('  \u2705 All Copilot generated files are fresh');
+} catch (err: any) {
+  hasErrors = true;
+  const output = err.stdout?.toString() || '';
+  console.log('  \u274c Copilot generated files are stale:');
+  for (const line of output.split('\n').filter((l: string) => l.startsWith('STALE'))) {
+    console.log(`      ${line}`);
+  }
+  console.log('      Run: bun run gen:skill-docs --host copilot');
+}
+
 console.log('');
 process.exit(hasErrors ? 1 : 0);

From 084b0f4e55f3c3a1bd8e3dc321e96609e9444bd7 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:23:53 -0400
Subject: [PATCH 05/15] feat: add copilot to build pipeline and package
 description

Build script now generates skill docs for copilot host alongside
claude and codex. Package description mentions Copilot CLI.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 package.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/package.json b/package.json
index b24b52535..412b9bde4 100644
--- a/package.json
+++ b/package.json
@@ -1,14 +1,14 @@
 {
   "name": "gstack",
   "version": "0.11.9.0",
-  "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
+  "description": "Garry's Stack — Claude Code / Codex / Copilot CLI skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",
   "bin": {
     "browse": "./browse/dist/browse"
   },
   "scripts": {
-    "build": "bun run gen:skill-docs && bun run gen:skill-docs --host codex && bun build --compile browse/src/cli.ts --outfile browse/dist/browse && bun build --compile browse/src/find-browse.ts --outfile browse/dist/find-browse && bun build --compile bin/gstack-global-discover.ts --outfile bin/gstack-global-discover && bash browse/scripts/build-node-server.sh && git rev-parse HEAD > browse/dist/.version && rm -f .*.bun-build || true",
+    "build": "bun run gen:skill-docs && bun run gen:skill-docs --host codex && bun run gen:skill-docs --host copilot && bun build --compile browse/src/cli.ts --outfile browse/dist/browse && bun build --compile browse/src/find-browse.ts --outfile browse/dist/find-browse && bun build --compile bin/gstack-global-discover.ts --outfile bin/gstack-global-discover && bash browse/scripts/build-node-server.sh && git rev-parse HEAD > browse/dist/.version && rm -f .*.bun-build || true",
     "gen:skill-docs": "bun run scripts/gen-skill-docs.ts",
     "dev": "bun run browse/src/cli.ts",
     "server": "bun run browse/src/server.ts",

From db8552f0a530b893074075289e32cf94eff4b91f Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:24:07 -0400
Subject: [PATCH 06/15] ci: add copilot host freshness check to skill-docs
 workflow

Verify that gen-skill-docs --host copilot succeeds alongside the
existing claude and codex checks.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .github/workflows/skill-docs.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/skill-docs.yml b/.github/workflows/skill-docs.yml
index c9c96d8e6..11e74d4a7 100644
--- a/.github/workflows/skill-docs.yml
+++ b/.github/workflows/skill-docs.yml
@@ -12,3 +12,5 @@ jobs:
       - run: git diff --exit-code || (echo "Generated SKILL.md files are stale. Run: bun run gen:skill-docs" && exit 1)
       - name: Check Codex host generation succeeds
         run: bun run gen:skill-docs --host codex
+      - name: Check Copilot host generation succeeds
+        run: bun run gen:skill-docs --host copilot

From eca7a4bd37c45bf9cbe20f4bfb2ec17d878fc50b Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:25:15 -0400
Subject: [PATCH 07/15] docs: add Copilot CLI to README install instructions
 and AGENTS.md

Add copilot alongside codex in the multi-agent install section.
Document --host copilot flag and ~/.copilot/skills/ install path.
Add Copilot to the retro global tool list and AGENTS.md gen command.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 AGENTS.md |  1 +
 README.md | 15 ++++++++-------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/AGENTS.md b/AGENTS.md
index d87217453..2ac79a8ee 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -45,5 +45,6 @@ bun run skill:check      # health dashboard for all skills
 
 - SKILL.md files are **generated** from `.tmpl` templates. Edit the template, not the output.
 - Run `bun run gen:skill-docs --host codex` to regenerate Codex-specific output.
+- Run `bun run gen:skill-docs --host copilot` to regenerate Copilot-specific output.
 - The browse binary provides headless browser access. Use `$B <command>` in skills.
 - Safety skills (careful, freeze, guard) use inline advisory prose — always confirm before destructive operations.
diff --git a/README.md b/README.md
index 253d54252..128a612da 100644
--- a/README.md
+++ b/README.md
@@ -54,7 +54,7 @@ Open Claude Code and paste this. Claude does the rest.
 
 Real files get committed to your repo (not a submodule), so `git clone` just works. Everything lives inside `.claude/`. Nothing touches your PATH or runs in the background.
 
-### Codex, Gemini CLI, or Cursor
+### Codex, Gemini CLI, Copilot CLI, or Cursor
 
 gstack works on any agent that supports the [SKILL.md standard](https://github.com/anthropics/claude-code). Skills live in `.agents/skills/` and are discovered automatically.
 
@@ -62,20 +62,21 @@ Install to one repo:
 
 ```bash
 git clone https://github.com/garrytan/gstack.git .agents/skills/gstack
-cd .agents/skills/gstack && ./setup --host codex
+cd .agents/skills/gstack && ./setup --host codex   # or --host copilot
 ```
 
-When setup runs from `.agents/skills/gstack`, it installs the generated Codex skills next to it in the same repo and does not write to `~/.codex/skills`.
+When setup runs from `.agents/skills/gstack`, it installs the generated Codex/Copilot skills next to it in the same repo and does not write to `~/.codex/skills` or `~/.copilot/skills`.
 
 Install once for your user account:
 
 ```bash
 git clone https://github.com/garrytan/gstack.git ~/gstack
-cd ~/gstack && ./setup --host codex
+cd ~/gstack && ./setup --host codex   # or --host copilot
 ```
 
 `setup --host codex` creates the runtime root at `~/.codex/skills/gstack` and
-links the generated Codex skills at the top level. This avoids duplicate skill
+links the generated Codex skills at the top level. `setup --host copilot` does
+the same at `~/.copilot/skills/gstack`. This avoids duplicate skill
 discovery from the source repo checkout.
 
 Or let setup auto-detect which agents you have installed:
@@ -85,7 +86,7 @@ git clone https://github.com/garrytan/gstack.git ~/gstack
 cd ~/gstack && ./setup --host auto
 ```
 
-For Codex-compatible hosts, setup now supports both repo-local installs from `.agents/skills/gstack` and user-global installs from `~/.codex/skills/gstack`. All 28 skills work across all supported agents. Hook-based safety skills (careful, freeze, guard) use inline safety advisory prose on non-Claude hosts.
+For Codex/Copilot-compatible hosts, setup now supports both repo-local installs from `.agents/skills/gstack` and user-global installs from `~/.codex/skills/gstack` or `~/.copilot/skills/gstack`. All 28 skills work across all supported agents. Hook-based safety skills (careful, freeze, guard) use inline safety advisory prose on non-Claude hosts.
 
 ## See it work
 
@@ -156,7 +157,7 @@ Each skill feeds into the next. `/office-hours` writes a design doc that `/plan-
 | `/canary` | **SRE** | Post-deploy monitoring loop. Watches for console errors, performance regressions, and page failures. |
 | `/benchmark` | **Performance Engineer** | Baseline page load times, Core Web Vitals, and resource sizes. Compare before/after on every PR. |
 | `/document-release` | **Technical Writer** | Update all project docs to match what you just shipped. Catches stale READMEs automatically. |
-| `/retro` | **Eng Manager** | Team-aware weekly retro. Per-person breakdowns, shipping streaks, test health trends, growth opportunities. `/retro global` runs across all your projects and AI tools (Claude Code, Codex, Gemini). |
+| `/retro` | **Eng Manager** | Team-aware weekly retro. Per-person breakdowns, shipping streaks, test health trends, growth opportunities. `/retro global` runs across all your projects and AI tools (Claude Code, Codex, Gemini, Copilot). |
 | `/browse` | **QA Engineer** | Real Chromium browser, real clicks, real screenshots. ~100ms per command. |
 | `/setup-browser-cookies` | **Session Manager** | Import cookies from your real browser (Chrome, Arc, Brave, Edge) into the headless session. Test authenticated pages. |
 | `/autoplan` | **Review Pipeline** | One command, fully reviewed plan. Runs CEO → design → eng review automatically with encoded decision principles. Surfaces only taste decisions for your approval. |

From 5faf8cdcfca91823bb8b6d13b717673e12454325 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:27:11 -0400
Subject: [PATCH 08/15] test: add Copilot CLI E2E tests and update existing
 test expectations

- Create copilot-session-runner.ts paralleling codex-session-runner.ts
- Create copilot-e2e.test.ts paralleling codex-e2e.test.ts
- Update gen-skill-docs tests to expect --host copilot support
- Update global-discover tests to expect copilot session property
- Add test:copilot and test:copilot:all npm scripts
- Include copilot-e2e.test.ts in eval/e2e test suites

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 package.json                           |  12 ++-
 test/copilot-e2e.test.ts               | 118 +++++++++++++++++++++
 test/gen-skill-docs.test.ts            |   7 +-
 test/global-discover.test.ts           |   4 +-
 test/helpers/copilot-session-runner.ts | 138 +++++++++++++++++++++++++
 5 files changed, 270 insertions(+), 9 deletions(-)
 create mode 100644 test/copilot-e2e.test.ts
 create mode 100644 test/helpers/copilot-session-runner.ts

diff --git a/package.json b/package.json
index 412b9bde4..507764d36 100644
--- a/package.json
+++ b/package.json
@@ -12,16 +12,18 @@
     "gen:skill-docs": "bun run scripts/gen-skill-docs.ts",
     "dev": "bun run browse/src/cli.ts",
     "server": "bun run browse/src/server.ts",
-    "test": "bun test browse/test/ test/ --ignore 'test/skill-e2e-*.test.ts' --ignore test/skill-llm-eval.test.ts --ignore test/skill-routing-e2e.test.ts --ignore test/codex-e2e.test.ts --ignore test/gemini-e2e.test.ts",
-    "test:evals": "EVALS=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-llm-eval.test.ts test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts",
-    "test:evals:all": "EVALS=1 EVALS_ALL=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-llm-eval.test.ts test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts",
-    "test:e2e": "EVALS=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts",
-    "test:e2e:all": "EVALS=1 EVALS_ALL=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts",
+    "test": "bun test browse/test/ test/ --ignore 'test/skill-e2e-*.test.ts' --ignore test/skill-llm-eval.test.ts --ignore test/skill-routing-e2e.test.ts --ignore test/codex-e2e.test.ts --ignore test/gemini-e2e.test.ts --ignore test/copilot-e2e.test.ts",
+    "test:evals": "EVALS=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-llm-eval.test.ts test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts test/copilot-e2e.test.ts",
+    "test:evals:all": "EVALS=1 EVALS_ALL=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-llm-eval.test.ts test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts test/copilot-e2e.test.ts",
+    "test:e2e": "EVALS=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts test/copilot-e2e.test.ts",
+    "test:e2e:all": "EVALS=1 EVALS_ALL=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts test/codex-e2e.test.ts test/gemini-e2e.test.ts test/copilot-e2e.test.ts",
     "test:e2e:fast": "EVALS=1 EVALS_FAST=1 bun test --retry 2 --concurrent --max-concurrency ${EVALS_CONCURRENCY:-15} test/skill-e2e-*.test.ts test/skill-routing-e2e.test.ts",
     "test:codex": "EVALS=1 bun test test/codex-e2e.test.ts",
     "test:codex:all": "EVALS=1 EVALS_ALL=1 bun test test/codex-e2e.test.ts",
     "test:gemini": "EVALS=1 bun test test/gemini-e2e.test.ts",
     "test:gemini:all": "EVALS=1 EVALS_ALL=1 bun test test/gemini-e2e.test.ts",
+    "test:copilot": "EVALS=1 bun test test/copilot-e2e.test.ts",
+    "test:copilot:all": "EVALS=1 EVALS_ALL=1 bun test test/copilot-e2e.test.ts",
     "skill:check": "bun run scripts/skill-check.ts",
     "dev:skill": "bun run scripts/dev-skill.ts",
     "start": "bun run browse/src/server.ts",
diff --git a/test/copilot-e2e.test.ts b/test/copilot-e2e.test.ts
new file mode 100644
index 000000000..dab882256
--- /dev/null
+++ b/test/copilot-e2e.test.ts
@@ -0,0 +1,118 @@
+/**
+ * Copilot CLI E2E tests — verify skills work when invoked by GitHub Copilot CLI.
+ *
+ * Spawns `gh copilot suggest` with skills installed in a temp HOME, captures
+ * output, and validates results. Follows the same pattern as codex-e2e.test.ts
+ * but adapted for the GitHub Copilot CLI (gh extension).
+ *
+ * Prerequisites:
+ * - `gh` CLI installed with the copilot extension (`gh extension install github/gh-copilot`)
+ * - Copilot authenticated via GitHub CLI
+ * - EVALS=1 env var set (same gate as Claude/Codex E2E tests)
+ *
+ * Skips gracefully when prerequisites are not met.
+ */
+
+import { describe, test, expect, afterAll } from 'bun:test';
+import { runCopilotSkill, installSkillToTempHome } from './helpers/copilot-session-runner';
+import type { CopilotResult } from './helpers/copilot-session-runner';
+import { EvalCollector } from './helpers/eval-store';
+import type { EvalTestEntry } from './helpers/eval-store';
+import { selectTests, detectBaseBranch, getChangedFiles, E2E_TOUCHFILES, GLOBAL_TOUCHFILES } from './helpers/touchfiles';
+import * as fs from 'fs';
+import * as path from 'path';
+import * as os from 'os';
+
+const ROOT = path.resolve(import.meta.dir, '..');
+
+// --- Prerequisites check ---
+
+const COPILOT_AVAILABLE = (() => {
+  try {
+    const result = Bun.spawnSync(['gh', 'copilot', '--version']);
+    return result.exitCode === 0;
+  } catch { return false; }
+})();
+
+const evalsEnabled = !!process.env.EVALS;
+
+// Skip all tests if gh copilot is not available or EVALS is not set.
+const SKIP = !COPILOT_AVAILABLE || !evalsEnabled;
+
+const describeCopilot = SKIP ? describe.skip : describe;
+
+// Log why we're skipping (helpful for debugging CI)
+if (!evalsEnabled) {
+  // Silent — same as Claude/Codex E2E tests, EVALS=1 required
+} else if (!COPILOT_AVAILABLE) {
+  process.stderr.write('\nCopilot E2E: SKIPPED — gh copilot not found (install: gh extension install github/gh-copilot)\n');
+}
+
+// --- Diff-based test selection ---
+
+// Copilot E2E touchfiles — keyed by test name, same pattern as Codex E2E_TOUCHFILES
+const COPILOT_E2E_TOUCHFILES: Record<string, string[]> = {
+  'copilot-discover-skill':    ['codex/**', '.agents/skills/**', 'test/helpers/copilot-session-runner.ts'],
+};
+
+let selectedTests: string[] | null = null; // null = run all
+
+// --- Eval collector ---
+
+const evalCollector = new EvalCollector('copilot-e2e');
+
+afterAll(async () => {
+  if (!SKIP) {
+    await evalCollector.flush();
+  }
+});
+
+// --- Tests ---
+
+describeCopilot('Copilot CLI E2E', () => {
+  test('copilot-discover-skill: gh copilot can suggest with gstack skill context', async () => {
+    // Diff-based test selection
+    if (selectedTests !== null && !selectedTests.includes('copilot-discover-skill')) {
+      return; // skip — not affected by current diff
+    }
+
+    const agentsDir = path.join(ROOT, '.agents', 'skills');
+    if (!fs.existsSync(agentsDir)) {
+      process.stderr.write('  Copilot E2E: .agents/skills/ not found — skipping\n');
+      return;
+    }
+
+    // Use the generated root gstack skill
+    const skillDir = path.join(agentsDir, 'gstack');
+    if (!fs.existsSync(path.join(skillDir, 'SKILL.md'))) {
+      process.stderr.write('  Copilot E2E: gstack SKILL.md not found in .agents/skills/ — skipping\n');
+      return;
+    }
+
+    const result = await runCopilotSkill({
+      skillDir,
+      prompt: 'list available gstack skills',
+      timeoutMs: 120_000,
+      cwd: ROOT,
+      skillName: 'gstack',
+    });
+
+    // Record eval
+    const entry: EvalTestEntry = {
+      test_name: 'copilot-discover-skill',
+      skill_name: 'gstack',
+      host: 'copilot',
+      prompt: 'list available gstack skills',
+      expected_behavior: 'Copilot acknowledges gstack skill context',
+      actual_output: result.output.slice(0, 1000),
+      exit_code: result.exitCode,
+      duration_ms: result.durationMs,
+      pass: result.exitCode === 0 && result.output.length > 0,
+    };
+    evalCollector.add(entry);
+
+    // Basic validation — copilot ran and produced output
+    expect(result.exitCode).toBe(0);
+    expect(result.output.length).toBeGreaterThan(0);
+  }, 180_000);
+});
diff --git a/test/gen-skill-docs.test.ts b/test/gen-skill-docs.test.ts
index 32e77a368..c04ccdff7 100644
--- a/test/gen-skill-docs.test.ts
+++ b/test/gen-skill-docs.test.ts
@@ -1308,14 +1308,15 @@ describe('setup script validation', () => {
     expect(fnBody).toContain('ln -snf "gstack/$skill_name"');
   });
 
-  test('setup supports --host auto|claude|codex|kiro', () => {
+  test('setup supports --host auto|claude|codex|copilot|kiro', () => {
     expect(setupContent).toContain('--host');
-    expect(setupContent).toContain('claude|codex|kiro|auto');
+    expect(setupContent).toContain('claude|codex|copilot|kiro|auto');
   });
 
-  test('auto mode detects claude, codex, and kiro binaries', () => {
+  test('auto mode detects claude, codex, copilot, and kiro binaries', () => {
     expect(setupContent).toContain('command -v claude');
     expect(setupContent).toContain('command -v codex');
+    expect(setupContent).toContain('gh copilot --version');
     expect(setupContent).toContain('command -v kiro-cli');
   });
 
diff --git a/test/global-discover.test.ts b/test/global-discover.test.ts
index c8d489f4a..aecd2c8ff 100644
--- a/test/global-discover.test.ts
+++ b/test/global-discover.test.ts
@@ -151,6 +151,7 @@ describe("gstack-global-discover", () => {
         expect(repo.sessions).toHaveProperty("claude_code");
         expect(repo.sessions).toHaveProperty("codex");
         expect(repo.sessions).toHaveProperty("gemini");
+        expect(repo.sessions).toHaveProperty("copilot");
       }
     });
 
@@ -166,7 +167,8 @@ describe("gstack-global-discover", () => {
       const toolTotal =
         json.tools.claude_code.total_sessions +
         json.tools.codex.total_sessions +
-        json.tools.gemini.total_sessions;
+        json.tools.gemini.total_sessions +
+        json.tools.copilot.total_sessions;
       expect(json.total_sessions).toBe(toolTotal);
     });
 
diff --git a/test/helpers/copilot-session-runner.ts b/test/helpers/copilot-session-runner.ts
new file mode 100644
index 000000000..afca4f2a3
--- /dev/null
+++ b/test/helpers/copilot-session-runner.ts
@@ -0,0 +1,138 @@
+/**
+ * Copilot CLI subprocess runner for skill E2E testing.
+ *
+ * Spawns `gh copilot suggest` as a completely independent process and returns
+ * structured results. Follows the same pattern as codex-session-runner.ts but
+ * adapted for the GitHub Copilot CLI (gh copilot extension).
+ *
+ * Key differences from Codex session-runner:
+ * - Uses `gh copilot suggest` instead of `codex exec`
+ * - Copilot CLI is a gh extension, not a standalone binary
+ * - Needs temp HOME with skill installed at ~/.copilot/skills/{skillName}/SKILL.md
+ */
+
+import * as fs from 'fs';
+import * as path from 'path';
+import * as os from 'os';
+
+// --- Interfaces ---
+
+export interface CopilotResult {
+  output: string;           // Full agent message text
+  exitCode: number;         // Process exit code
+  durationMs: number;       // Wall clock time
+  rawOutput: string;        // Raw stdout for debugging
+}
+
+// --- Skill installation helper ---
+
+/**
+ * Install a SKILL.md into a temp HOME directory for Copilot to discover.
+ * Creates ~/.copilot/skills/{skillName}/SKILL.md in the temp HOME.
+ *
+ * Returns the temp HOME path. Caller is responsible for cleanup.
+ */
+export function installSkillToTempHome(
+  skillDir: string,
+  skillName: string,
+  tempHome?: string,
+): string {
+  const home = tempHome || fs.mkdtempSync(path.join(os.tmpdir(), 'copilot-e2e-'));
+  const destDir = path.join(home, '.copilot', 'skills', skillName);
+  fs.mkdirSync(destDir, { recursive: true });
+
+  const srcSkill = path.join(skillDir, 'SKILL.md');
+  if (fs.existsSync(srcSkill)) {
+    fs.copyFileSync(srcSkill, path.join(destDir, 'SKILL.md'));
+  }
+
+  return home;
+}
+
+// --- Main runner ---
+
+/**
+ * Run a Copilot skill via `gh copilot suggest` and return structured results.
+ *
+ * Spawns gh copilot in a temp HOME with the skill installed, captures output,
+ * and returns a CopilotResult. Skips gracefully if gh copilot is not found.
+ */
+export async function runCopilotSkill(opts: {
+  skillDir: string;         // Path to skill directory containing SKILL.md
+  prompt: string;           // What to ask Copilot to suggest
+  timeoutMs?: number;       // Default 300000 (5 min)
+  cwd?: string;             // Working directory
+  skillName?: string;       // Skill name for installation (default: dirname)
+}): Promise<CopilotResult> {
+  const {
+    skillDir,
+    prompt,
+    timeoutMs = 300_000,
+    cwd,
+    skillName,
+  } = opts;
+
+  const startTime = Date.now();
+  const name = skillName || path.basename(skillDir) || 'gstack';
+
+  // Check if gh copilot is available
+  const whichResult = Bun.spawnSync(['gh', 'copilot', '--version']);
+  if (whichResult.exitCode !== 0) {
+    return {
+      output: 'SKIP: gh copilot not found',
+      exitCode: -1,
+      durationMs: Date.now() - startTime,
+      rawOutput: '',
+    };
+  }
+
+  // Set up temp HOME with skill installed
+  const tempHome = fs.mkdtempSync(path.join(os.tmpdir(), 'copilot-e2e-'));
+
+  try {
+    installSkillToTempHome(skillDir, name, tempHome);
+
+    // Build gh copilot suggest command
+    const args = ['copilot', 'suggest', '-t', 'shell', prompt];
+
+    // Spawn gh copilot with temp HOME
+    const proc = Bun.spawn(['gh', ...args], {
+      cwd: cwd || skillDir,
+      stdout: 'pipe',
+      stderr: 'pipe',
+      env: {
+        ...process.env,
+        HOME: tempHome,
+      },
+    });
+
+    // Race against timeout
+    let timedOut = false;
+    const timeoutId = setTimeout(() => {
+      timedOut = true;
+      proc.kill();
+    }, timeoutMs);
+
+    const stdoutText = await new Response(proc.stdout).text();
+    const stderrText = await new Response(proc.stderr).text();
+    const exitCode = await proc.exited;
+    clearTimeout(timeoutId);
+
+    const durationMs = Date.now() - startTime;
+
+    // Log stderr if non-empty
+    if (stderrText.trim()) {
+      process.stderr.write(`  [copilot stderr] ${stderrText.trim().slice(0, 200)}\n`);
+    }
+
+    return {
+      output: stdoutText.trim(),
+      exitCode: timedOut ? 124 : exitCode,
+      durationMs,
+      rawOutput: stdoutText,
+    };
+  } finally {
+    // Clean up temp HOME
+    try { fs.rmSync(tempHome, { recursive: true, force: true }); } catch { /* non-fatal */ }
+  }
+}

From 746db55b4d51980c563479ab1be91b1bc212c4ba Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:32:51 -0400
Subject: [PATCH 09/15] docs: update CONTRIBUTING.md for multi-host development
 with Copilot

Rename 'Dual-host' section to 'Multi-host', add copilot generation
commands, update comparison table, and add copilot to new skill
instructions and freshness check commands.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 CONTRIBUTING.md | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c4c315716..517bff50e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -213,11 +213,12 @@ SKILL.md files are **generated** from `.tmpl` templates. Don't edit the `.md` di
 # 1. Edit the template
 vim SKILL.md.tmpl              # or browse/SKILL.md.tmpl
 
-# 2. Regenerate for both hosts
+# 2. Regenerate for all hosts
 bun run gen:skill-docs
 bun run gen:skill-docs --host codex
+bun run gen:skill-docs --host copilot
 
-# 3. Check health (reports both Claude and Codex)
+# 3. Check health (reports Claude, Codex, and Copilot)
 bun run skill:check
 
 # Or use watch mode — auto-regenerates on save
@@ -228,11 +229,11 @@ For template authoring best practices (natural language over bash-isms, dynamic
 
 To add a browse command, add it to `browse/src/commands.ts`. To add a snapshot flag, add it to `SNAPSHOT_FLAGS` in `browse/src/snapshot.ts`. Then rebuild.
 
-## Dual-host development (Claude + Codex)
+## Multi-host development (Claude + Codex + Copilot)
 
-gstack generates SKILL.md files for two hosts: **Claude** (`.claude/skills/`) and **Codex** (`.agents/skills/`). Every template change needs to be generated for both.
+gstack generates SKILL.md files for multiple hosts: **Claude** (`.claude/skills/`), **Codex** (`.agents/skills/`), and **Copilot** (`.agents/skills/`). Codex and Copilot share the same `.agents/skills/` output directory. Every template change needs to be generated for all hosts.
 
-### Generating for both hosts
+### Generating for all hosts
 
 ```bash
 # Generate Claude output (default)
@@ -242,43 +243,47 @@ bun run gen:skill-docs
 bun run gen:skill-docs --host codex
 # --host agents is an alias for --host codex
 
-# Or use build, which does both + compiles binaries
+# Generate Copilot output (same .agents/skills/ directory as codex)
+bun run gen:skill-docs --host copilot
+
+# Or use build, which does all three + compiles binaries
 bun run build
 ```
 
 ### What changes between hosts
 
-| Aspect | Claude | Codex |
-|--------|--------|-------|
+| Aspect | Claude | Codex / Copilot |
+|--------|--------|-----------------|
 | Output directory | `{skill}/SKILL.md` | `.agents/skills/gstack-{skill}/SKILL.md` (generated at setup, gitignored) |
 | Frontmatter | Full (name, description, allowed-tools, hooks, version) | Minimal (name + description only) |
-| Paths | `~/.claude/skills/gstack` | `$GSTACK_ROOT` (`.agents/skills/gstack` in a repo, otherwise `~/.codex/skills/gstack`) |
+| Paths | `~/.claude/skills/gstack` | `$GSTACK_ROOT` (`.agents/skills/gstack` in a repo, otherwise `~/.codex/skills/gstack` or `~/.copilot/skills/gstack`) |
 | Hook skills | `hooks:` frontmatter (enforced by Claude) | Inline safety advisory prose (advisory only) |
 | `/codex` skill | Included (Claude wraps codex exec) | Excluded (self-referential) |
 
-### Testing Codex output
+### Testing Codex/Copilot output
 
 ```bash
-# Run all static tests (includes Codex validation)
+# Run all static tests (includes Codex/Copilot validation)
 bun test
 
-# Check freshness for both hosts
+# Check freshness for all hosts
 bun run gen:skill-docs --dry-run
 bun run gen:skill-docs --host codex --dry-run
+bun run gen:skill-docs --host copilot --dry-run
 
-# Health dashboard covers both hosts
+# Health dashboard covers all hosts
 bun run skill:check
 ```
 
 ### Dev setup for .agents/
 
-When you run `bin/dev-setup`, it creates symlinks in both `.claude/skills/` and `.agents/skills/` (if applicable), so Codex-compatible agents can discover your dev skills too. The `.agents/` directory is generated at setup time from `.tmpl` templates — it is gitignored and not committed.
+When you run `bin/dev-setup`, it creates symlinks in both `.claude/skills/` and `.agents/skills/` (if applicable), so Codex/Copilot-compatible agents can discover your dev skills too. The `.agents/` directory is generated at setup time from `.tmpl` templates — it is gitignored and not committed.
 
 ### Adding a new skill
 
 When you add a new skill template, both hosts get it automatically:
 1. Create `{skill}/SKILL.md.tmpl`
-2. Run `bun run gen:skill-docs` (Claude output) and `bun run gen:skill-docs --host codex` (Codex output)
+2. Run `bun run gen:skill-docs` (Claude output), `bun run gen:skill-docs --host codex` (Codex output), and `bun run gen:skill-docs --host copilot` (Copilot output)
 3. The dynamic template discovery picks it up — no static list to update
 4. Commit `{skill}/SKILL.md` — `.agents/` is generated at setup time and gitignored
 

From c5247f33e5df7c60b02afad1a4140ec8889db001 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:33:24 -0400
Subject: [PATCH 10/15] docs: mention Copilot E2E test prerequisites in
 CLAUDE.md

Add note about gh CLI + copilot extension requirement for the
copilot-e2e.test.ts E2E tests.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 CLAUDE.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CLAUDE.md b/CLAUDE.md
index 5c0389c1f..081bffe6b 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -22,6 +22,7 @@ bun run eval:summary # aggregate stats across all eval runs
 
 `test:evals` requires `ANTHROPIC_API_KEY`. Codex E2E tests (`test/codex-e2e.test.ts`)
 use Codex's own auth from `~/.codex/` config — no `OPENAI_API_KEY` env var needed.
+Copilot E2E tests (`test/copilot-e2e.test.ts`) require `gh` CLI with the copilot extension.
 E2E tests stream progress in real-time (tool-by-tool via `--output-format stream-json
 --verbose`). Results are persisted to `~/.gstack-dev/evals/` with auto-comparison
 against the previous run.

From bbb58277d8d3d5f2e98d855547431bd68c249da7 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:42:35 -0400
Subject: [PATCH 11/15] fix: update Copilot CLI references from gh extension to
 standalone app

The GitHub Copilot CLI went GA in February 2026 as a standalone binary
(\copilot\) installed via \
pm install -g @github/copilot\. Update all
references from the old gh extension (\gh copilot\) to the new standalone:

- setup: auto-detect via \command -v copilot\ (not gh copilot --version)
- gstack-global-discover: scan ~/.copilot/session-state/ (not ~/.config/gh-copilot/)
- copilot-e2e.test.ts: check for \copilot\ binary, update skip messages
- copilot-session-runner.ts: spawn \copilot -p\ (not gh copilot suggest)
- gen-skill-docs.test.ts: update auto-detect assertion
- CLAUDE.md: update prereqs note

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 CLAUDE.md                              |  2 +-
 bin/gstack-global-discover.ts          |  4 ++--
 setup                                  |  2 +-
 test/copilot-e2e.test.ts               | 16 +++++++--------
 test/gen-skill-docs.test.ts            |  2 +-
 test/helpers/copilot-session-runner.ts | 28 +++++++++++++-------------
 6 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/CLAUDE.md b/CLAUDE.md
index 081bffe6b..bc603356a 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -22,7 +22,7 @@ bun run eval:summary # aggregate stats across all eval runs
 
 `test:evals` requires `ANTHROPIC_API_KEY`. Codex E2E tests (`test/codex-e2e.test.ts`)
 use Codex's own auth from `~/.codex/` config — no `OPENAI_API_KEY` env var needed.
-Copilot E2E tests (`test/copilot-e2e.test.ts`) require `gh` CLI with the copilot extension.
+Copilot E2E tests (`test/copilot-e2e.test.ts`) require the standalone Copilot CLI (`npm install -g @github/copilot`).
 E2E tests stream progress in real-time (tool-by-tool via `--output-format stream-json
 --verbose`). Results are persisted to `~/.gstack-dev/evals/` with auto-comparison
 against the previous run.
diff --git a/bin/gstack-global-discover.ts b/bin/gstack-global-discover.ts
index 810d41d6a..98ffaade6 100644
--- a/bin/gstack-global-discover.ts
+++ b/bin/gstack-global-discover.ts
@@ -442,8 +442,8 @@ function scanGemini(since: Date): Session[] {
 }
 
 function scanCopilot(since: Date): Session[] {
-  // GitHub Copilot CLI stores conversation history in ~/.config/gh-copilot/
-  const configDir = join(homedir(), ".config", "gh-copilot");
+  // GitHub Copilot CLI (standalone) stores session data in ~/.copilot/session-state/
+  const configDir = join(homedir(), ".copilot", "session-state");
   if (!existsSync(configDir)) return [];
 
   const sessions: Session[] = [];
diff --git a/setup b/setup
index 544cae3d0..9686c68b3 100755
--- a/setup
+++ b/setup
@@ -45,7 +45,7 @@ INSTALL_KIRO=0
 if [ "$HOST" = "auto" ]; then
   command -v claude >/dev/null 2>&1 && INSTALL_CLAUDE=1
   command -v codex >/dev/null 2>&1 && INSTALL_CODEX=1
-  command -v gh >/dev/null 2>&1 && gh copilot --version >/dev/null 2>&1 && INSTALL_COPILOT=1
+  command -v copilot >/dev/null 2>&1 && INSTALL_COPILOT=1
   command -v kiro-cli >/dev/null 2>&1 && INSTALL_KIRO=1
   # If none found, default to claude
   if [ "$INSTALL_CLAUDE" -eq 0 ] && [ "$INSTALL_CODEX" -eq 0 ] && [ "$INSTALL_COPILOT" -eq 0 ] && [ "$INSTALL_KIRO" -eq 0 ]; then
diff --git a/test/copilot-e2e.test.ts b/test/copilot-e2e.test.ts
index dab882256..bac72ef7b 100644
--- a/test/copilot-e2e.test.ts
+++ b/test/copilot-e2e.test.ts
@@ -1,13 +1,13 @@
 /**
  * Copilot CLI E2E tests — verify skills work when invoked by GitHub Copilot CLI.
  *
- * Spawns `gh copilot suggest` with skills installed in a temp HOME, captures
+ * Spawns `copilot -p` with skills installed in a temp HOME, captures
  * output, and validates results. Follows the same pattern as codex-e2e.test.ts
- * but adapted for the GitHub Copilot CLI (gh extension).
+ * but adapted for the standalone GitHub Copilot CLI.
  *
  * Prerequisites:
- * - `gh` CLI installed with the copilot extension (`gh extension install github/gh-copilot`)
- * - Copilot authenticated via GitHub CLI
+ * - Copilot CLI installed (`npm install -g @github/copilot`)
+ * - Copilot authenticated (`copilot` → `/login`)
  * - EVALS=1 env var set (same gate as Claude/Codex E2E tests)
  *
  * Skips gracefully when prerequisites are not met.
@@ -29,14 +29,14 @@ const ROOT = path.resolve(import.meta.dir, '..');
 
 const COPILOT_AVAILABLE = (() => {
   try {
-    const result = Bun.spawnSync(['gh', 'copilot', '--version']);
+    const result = Bun.spawnSync(['copilot', '--version']);
     return result.exitCode === 0;
   } catch { return false; }
 })();
 
 const evalsEnabled = !!process.env.EVALS;
 
-// Skip all tests if gh copilot is not available or EVALS is not set.
+// Skip all tests if copilot CLI is not available or EVALS is not set.
 const SKIP = !COPILOT_AVAILABLE || !evalsEnabled;
 
 const describeCopilot = SKIP ? describe.skip : describe;
@@ -45,7 +45,7 @@ const describeCopilot = SKIP ? describe.skip : describe;
 if (!evalsEnabled) {
   // Silent — same as Claude/Codex E2E tests, EVALS=1 required
 } else if (!COPILOT_AVAILABLE) {
-  process.stderr.write('\nCopilot E2E: SKIPPED — gh copilot not found (install: gh extension install github/gh-copilot)\n');
+  process.stderr.write('\nCopilot E2E: SKIPPED — copilot CLI not found (install: npm install -g @github/copilot)\n');
 }
 
 // --- Diff-based test selection ---
@@ -70,7 +70,7 @@ afterAll(async () => {
 // --- Tests ---
 
 describeCopilot('Copilot CLI E2E', () => {
-  test('copilot-discover-skill: gh copilot can suggest with gstack skill context', async () => {
+  test('copilot-discover-skill: copilot CLI can run with gstack skill context', async () => {
     // Diff-based test selection
     if (selectedTests !== null && !selectedTests.includes('copilot-discover-skill')) {
       return; // skip — not affected by current diff
diff --git a/test/gen-skill-docs.test.ts b/test/gen-skill-docs.test.ts
index c04ccdff7..a992c5a21 100644
--- a/test/gen-skill-docs.test.ts
+++ b/test/gen-skill-docs.test.ts
@@ -1316,7 +1316,7 @@ describe('setup script validation', () => {
   test('auto mode detects claude, codex, copilot, and kiro binaries', () => {
     expect(setupContent).toContain('command -v claude');
     expect(setupContent).toContain('command -v codex');
-    expect(setupContent).toContain('gh copilot --version');
+    expect(setupContent).toContain('command -v copilot');
     expect(setupContent).toContain('command -v kiro-cli');
   });
 
diff --git a/test/helpers/copilot-session-runner.ts b/test/helpers/copilot-session-runner.ts
index afca4f2a3..99c43a360 100644
--- a/test/helpers/copilot-session-runner.ts
+++ b/test/helpers/copilot-session-runner.ts
@@ -1,13 +1,13 @@
 /**
  * Copilot CLI subprocess runner for skill E2E testing.
  *
- * Spawns `gh copilot suggest` as a completely independent process and returns
+ * Spawns `copilot -p` as a completely independent process and returns
  * structured results. Follows the same pattern as codex-session-runner.ts but
- * adapted for the GitHub Copilot CLI (gh copilot extension).
+ * adapted for the standalone GitHub Copilot CLI.
  *
  * Key differences from Codex session-runner:
- * - Uses `gh copilot suggest` instead of `codex exec`
- * - Copilot CLI is a gh extension, not a standalone binary
+ * - Uses `copilot -p` instead of `codex exec`
+ * - Copilot CLI is a standalone binary (not a gh extension)
  * - Needs temp HOME with skill installed at ~/.copilot/skills/{skillName}/SKILL.md
  */
 
@@ -52,10 +52,10 @@ export function installSkillToTempHome(
 // --- Main runner ---
 
 /**
- * Run a Copilot skill via `gh copilot suggest` and return structured results.
+ * Run a Copilot skill via `copilot -p` and return structured results.
  *
- * Spawns gh copilot in a temp HOME with the skill installed, captures output,
- * and returns a CopilotResult. Skips gracefully if gh copilot is not found.
+ * Spawns copilot in a temp HOME with the skill installed, captures output,
+ * and returns a CopilotResult. Skips gracefully if copilot is not found.
  */
 export async function runCopilotSkill(opts: {
   skillDir: string;         // Path to skill directory containing SKILL.md
@@ -75,11 +75,11 @@ export async function runCopilotSkill(opts: {
   const startTime = Date.now();
   const name = skillName || path.basename(skillDir) || 'gstack';
 
-  // Check if gh copilot is available
-  const whichResult = Bun.spawnSync(['gh', 'copilot', '--version']);
+  // Check if copilot CLI is available
+  const whichResult = Bun.spawnSync(['copilot', '--version']);
   if (whichResult.exitCode !== 0) {
     return {
-      output: 'SKIP: gh copilot not found',
+      output: 'SKIP: copilot CLI not found',
       exitCode: -1,
       durationMs: Date.now() - startTime,
       rawOutput: '',
@@ -92,11 +92,11 @@ export async function runCopilotSkill(opts: {
   try {
     installSkillToTempHome(skillDir, name, tempHome);
 
-    // Build gh copilot suggest command
-    const args = ['copilot', 'suggest', '-t', 'shell', prompt];
+    // Build copilot command
+    const args = ['-p', prompt];
 
-    // Spawn gh copilot with temp HOME
-    const proc = Bun.spawn(['gh', ...args], {
+    // Spawn copilot with temp HOME
+    const proc = Bun.spawn(['copilot', ...args], {
       cwd: cwd || skillDir,
       stdout: 'pipe',
       stderr: 'pipe',

From 8d6d1f61822769cff8277fbff9b2691ccf65a858 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 10:52:38 -0400
Subject: [PATCH 12/15] chore: bump version to 0.11.9.0 and add CHANGELOG entry
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Add Copilot CLI support changelog entry following the project's
user-facing style: what you can now do, not implementation details.
VERSION: 0.11.7.0 → 0.11.9.0.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 CHANGELOG.md | 16 ++++++++++++++++
 VERSION      |  2 +-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ed769e54..dbd496392 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,21 @@
 # Changelog
 
+## [0.11.10.0] - 2026-03-23 — Copilot CLI Support
+
+### Added
+
+- **gstack now works with GitHub Copilot CLI.** Run `./setup --host copilot` and all 28 skills install to `~/.copilot/skills/`. Works the same as Codex — skills live in `.agents/skills/` and are discovered automatically.
+- **Auto-detection finds Copilot CLI.** `./setup --host auto` now detects `copilot` alongside Claude Code, Codex, and Kiro. Install once, works everywhere.
+- **Session discovery includes Copilot.** The global discover tool (`bin/gstack-global-discover.ts`) scans `~/.copilot/session-state/` so `/retro` and cross-project dashboards count Copilot sessions.
+- **Health checks cover Copilot.** `bun run skill:check` and CI now verify Copilot skill freshness alongside Claude and Codex.
+
+### For contributors
+
+- Added `'copilot'` host type to `gen-skill-docs.ts`, `setup`, `gstack-global-discover.ts`, and `skill-check.ts`.
+- New E2E test infrastructure: `copilot-e2e.test.ts` and `copilot-session-runner.ts` paralleling Codex equivalents.
+- Updated `CONTRIBUTING.md` "Dual-host" → "Multi-host" with Copilot generation commands and testing guidance.
+- Targets the standalone GA Copilot CLI (`copilot` binary via `npm install -g @github/copilot`), not the legacy `gh copilot` extension.
+
 ## [0.11.9.0] - 2026-03-23 — Codex Skill Loading Fix
 
 ### Fixed
diff --git a/VERSION b/VERSION
index b1d9a7913..6bfbae754 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.11.9.0
+0.11.10.0

From 8c6f6d4465e127f5d2ca0a2867ad447bc5cce661 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 11:00:46 -0400
Subject: [PATCH 13/15] docs: treat Copilot as first-class throughout (not a
 Codex suffix)

Expand the host comparison table in CONTRIBUTING.md from 3 columns
(Claude | Codex / Copilot) to 4 columns (Claude | Codex | Copilot)
so each host has its own column. Replace 'Codex/Copilot' shorthand
with explicit enumeration in README.md, CONTRIBUTING.md, setup, and
gen-skill-docs.ts comments.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 CONTRIBUTING.md           | 20 ++++++++++----------
 README.md                 |  4 ++--
 scripts/gen-skill-docs.ts |  6 +++---
 setup                     |  6 +++---
 4 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 517bff50e..8cd0f5932 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -252,18 +252,18 @@ bun run build
 
 ### What changes between hosts
 
-| Aspect | Claude | Codex / Copilot |
-|--------|--------|-----------------|
-| Output directory | `{skill}/SKILL.md` | `.agents/skills/gstack-{skill}/SKILL.md` (generated at setup, gitignored) |
-| Frontmatter | Full (name, description, allowed-tools, hooks, version) | Minimal (name + description only) |
-| Paths | `~/.claude/skills/gstack` | `$GSTACK_ROOT` (`.agents/skills/gstack` in a repo, otherwise `~/.codex/skills/gstack` or `~/.copilot/skills/gstack`) |
-| Hook skills | `hooks:` frontmatter (enforced by Claude) | Inline safety advisory prose (advisory only) |
-| `/codex` skill | Included (Claude wraps codex exec) | Excluded (self-referential) |
+| Aspect | Claude | Codex | Copilot |
+|--------|--------|-------|---------|
+| Output directory | `{skill}/SKILL.md` | `.agents/skills/gstack-{skill}/SKILL.md` (generated at setup, gitignored) | `.agents/skills/gstack-{skill}/SKILL.md` (generated at setup, gitignored) |
+| Frontmatter | Full (name, description, allowed-tools, hooks, version) | Minimal (name + description only) | Minimal (name + description only) |
+| Paths | `~/.claude/skills/gstack` | `$GSTACK_ROOT` (`.agents/skills/gstack` in a repo, otherwise `~/.codex/skills/gstack`) | `$GSTACK_ROOT` (`.agents/skills/gstack` in a repo, otherwise `~/.copilot/skills/gstack`) |
+| Hook skills | `hooks:` frontmatter (enforced by Claude) | Inline safety advisory prose (advisory only) | Inline safety advisory prose (advisory only) |
+| `/codex` skill | Included (Claude wraps codex exec) | Excluded (self-referential) | Excluded (self-referential) |
 
-### Testing Codex/Copilot output
+### Testing Codex and Copilot output
 
 ```bash
-# Run all static tests (includes Codex/Copilot validation)
+# Run all static tests (includes Codex and Copilot validation)
 bun test
 
 # Check freshness for all hosts
@@ -277,7 +277,7 @@ bun run skill:check
 
 ### Dev setup for .agents/
 
-When you run `bin/dev-setup`, it creates symlinks in both `.claude/skills/` and `.agents/skills/` (if applicable), so Codex/Copilot-compatible agents can discover your dev skills too. The `.agents/` directory is generated at setup time from `.tmpl` templates — it is gitignored and not committed.
+When you run `bin/dev-setup`, it creates symlinks in both `.claude/skills/` and `.agents/skills/` (if applicable), so Codex, Copilot, and other compatible agents can discover your dev skills too. The `.agents/` directory is generated at setup time from `.tmpl` templates — it is gitignored and not committed.
 
 ### Adding a new skill
 
diff --git a/README.md b/README.md
index 128a612da..6bad1e848 100644
--- a/README.md
+++ b/README.md
@@ -65,7 +65,7 @@ git clone https://github.com/garrytan/gstack.git .agents/skills/gstack
 cd .agents/skills/gstack && ./setup --host codex   # or --host copilot
 ```
 
-When setup runs from `.agents/skills/gstack`, it installs the generated Codex/Copilot skills next to it in the same repo and does not write to `~/.codex/skills` or `~/.copilot/skills`.
+When setup runs from `.agents/skills/gstack`, it installs the generated Codex and Copilot skills next to it in the same repo and does not write to `~/.codex/skills` or `~/.copilot/skills`.
 
 Install once for your user account:
 
@@ -86,7 +86,7 @@ git clone https://github.com/garrytan/gstack.git ~/gstack
 cd ~/gstack && ./setup --host auto
 ```
 
-For Codex/Copilot-compatible hosts, setup now supports both repo-local installs from `.agents/skills/gstack` and user-global installs from `~/.codex/skills/gstack` or `~/.copilot/skills/gstack`. All 28 skills work across all supported agents. Hook-based safety skills (careful, freeze, guard) use inline safety advisory prose on non-Claude hosts.
+For Codex, Copilot, and other compatible hosts, setup supports both repo-local installs from `.agents/skills/gstack` and user-global installs from `~/.codex/skills/gstack` or `~/.copilot/skills/gstack`. All 28 skills work across all supported agents. Hook-based safety skills (careful, freeze, guard) use inline safety advisory prose on non-Claude hosts.
 
 ## See it work
 
diff --git a/scripts/gen-skill-docs.ts b/scripts/gen-skill-docs.ts
index 6a57ac641..2ad2ac890 100644
--- a/scripts/gen-skill-docs.ts
+++ b/scripts/gen-skill-docs.ts
@@ -2983,7 +2983,7 @@ function processTemplate(tmplPath: string, host: Host = 'claude'): { outputPath:
   // Determine skill directory relative to ROOT
   const skillDir = path.relative(ROOT, path.dirname(tmplPath));
 
-  // For codex/copilot host, route output to .agents/skills/{codexSkillName}/SKILL.md
+  // For non-Claude hosts (codex, copilot), route output to .agents/skills/{codexSkillName}/SKILL.md
   if (host === 'codex' || host === 'copilot') {
     const codexName = codexSkillName(skillDir === '.' ? '' : skillDir);
     outputDir = path.join(ROOT, '.agents', 'skills', codexName);
@@ -3016,7 +3016,7 @@ function processTemplate(tmplPath: string, host: Host = 'claude'): { outputPath:
     throw new Error(`Unresolved placeholders in ${relTmplPath}: ${remaining.join(', ')}`);
   }
 
-  // For codex/copilot host: transform frontmatter and replace Claude-specific paths
+  // For non-Claude hosts (codex, copilot): transform frontmatter and replace Claude-specific paths
   if (host === 'codex' || host === 'copilot') {
     // Extract hook safety prose BEFORE transforming frontmatter (which strips hooks)
     const safetyProse = extractHookSafetyProse(tmplContent);
@@ -3077,7 +3077,7 @@ function findTemplates(): string[] {
 let hasChanges = false;
 
 for (const tmplPath of findTemplates()) {
-  // Skip /codex skill for codex/copilot host (self-referential — it's a Claude wrapper around codex exec)
+  // Skip /codex skill for non-Claude hosts (self-referential — it's a Claude wrapper around codex exec)
   if (HOST === 'codex' || HOST === 'copilot') {
     const dir = path.basename(path.dirname(tmplPath));
     if (dir === 'codex') continue;
diff --git a/setup b/setup
index 9686c68b3..d23296d8c 100755
--- a/setup
+++ b/setup
@@ -139,7 +139,7 @@ fi
 # bun run build already does this, but we need it when NEEDS_BUILD=0 (binary is fresh).
 # Always regenerate: generation is fast (<2s) and mtime-based staleness checks are fragile
 # (miss stale files when timestamps match after clone/checkout/upgrade).
-# Codex and Copilot both use .agents/skills/ — generate once with --host codex.
+# Codex, Copilot, and other .agents/ hosts share .agents/skills/ — generate once with --host codex.
 AGENTS_DIR="$SOURCE_GSTACK_DIR/.agents/skills"
 NEEDS_AGENTS_GEN=1
 
@@ -482,8 +482,8 @@ if [ "$INSTALL_COPILOT" -eq 1 ]; then
   fi
 fi
 
-# 8. Create .agents/ sidecar symlinks for the real Codex/Copilot skill target.
-# The root Codex/Copilot skill ends up pointing at $SOURCE_GSTACK_DIR/.agents/skills/gstack,
+# 8. Create .agents/ sidecar symlinks for Codex and Copilot skill targets.
+# The root skill ends up pointing at $SOURCE_GSTACK_DIR/.agents/skills/gstack,
 # so the runtime assets must live there for both global and repo-local installs.
 if [ "$INSTALL_CODEX" -eq 1 ] || [ "$INSTALL_COPILOT" -eq 1 ]; then
   create_agents_sidecar "$SOURCE_GSTACK_DIR"

From 0a492bebae6051792631e9b1a6c47408351f3dc4 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 11:10:17 -0400
Subject: [PATCH 14/15] =?UTF-8?q?fix:=20address=20PR=20review=20=E2=80=94?=
 =?UTF-8?q?=20build=20overwrite,=20session=20scanning,=20and=20E2E=20auth?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fix three issues found in code review:

1. P1: Remove --host copilot from build pipeline, CI, and skill:check.
   Copilot and Codex share .agents/skills/ — running both overwrites
   codex output with copilot-flavored preambles. Copilot-specific paths
   are rewritten at setup time via sed (same pattern as Kiro).

2. P1: Rewrite scanCopilot() to walk session subdirectories.
   Copilot CLI stores sessions as ~/.copilot/session-state/{id}/ dirs
   containing events.jsonl and workspace.yaml, not top-level files.

3. P2: Copy auth config from real ~/.copilot/ to temp HOME in E2E runner.
   Without this, copilot -p in temp HOME loses login state and fails
   instead of running the test.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .github/workflows/skill-docs.yml       |  2 -
 AGENTS.md                              |  3 +-
 CONTRIBUTING.md                        | 17 +++----
 bin/gstack-global-discover.ts          | 64 ++++++++++++++++----------
 package.json                           |  2 +-
 scripts/skill-check.ts                 | 14 ------
 test/helpers/copilot-session-runner.ts | 12 +++++
 7 files changed, 60 insertions(+), 54 deletions(-)

diff --git a/.github/workflows/skill-docs.yml b/.github/workflows/skill-docs.yml
index 11e74d4a7..c9c96d8e6 100644
--- a/.github/workflows/skill-docs.yml
+++ b/.github/workflows/skill-docs.yml
@@ -12,5 +12,3 @@ jobs:
       - run: git diff --exit-code || (echo "Generated SKILL.md files are stale. Run: bun run gen:skill-docs" && exit 1)
       - name: Check Codex host generation succeeds
         run: bun run gen:skill-docs --host codex
-      - name: Check Copilot host generation succeeds
-        run: bun run gen:skill-docs --host copilot
diff --git a/AGENTS.md b/AGENTS.md
index 2ac79a8ee..fcb8e96f8 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -44,7 +44,6 @@ bun run skill:check      # health dashboard for all skills
 ## Key conventions
 
 - SKILL.md files are **generated** from `.tmpl` templates. Edit the template, not the output.
-- Run `bun run gen:skill-docs --host codex` to regenerate Codex-specific output.
-- Run `bun run gen:skill-docs --host copilot` to regenerate Copilot-specific output.
+- Run `bun run gen:skill-docs --host codex` to regenerate Codex output (Copilot derives from this at setup time).
 - The browse binary provides headless browser access. Use `$B <command>` in skills.
 - Safety skills (careful, freeze, guard) use inline advisory prose — always confirm before destructive operations.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8cd0f5932..2a8e22e39 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -216,9 +216,8 @@ vim SKILL.md.tmpl              # or browse/SKILL.md.tmpl
 # 2. Regenerate for all hosts
 bun run gen:skill-docs
 bun run gen:skill-docs --host codex
-bun run gen:skill-docs --host copilot
 
-# 3. Check health (reports Claude, Codex, and Copilot)
+# 3. Check health (reports Claude and Codex; Copilot derives from Codex at setup time)
 bun run skill:check
 
 # Or use watch mode — auto-regenerates on save
@@ -231,7 +230,7 @@ To add a browse command, add it to `browse/src/commands.ts`. To add a snapshot f
 
 ## Multi-host development (Claude + Codex + Copilot)
 
-gstack generates SKILL.md files for multiple hosts: **Claude** (`.claude/skills/`), **Codex** (`.agents/skills/`), and **Copilot** (`.agents/skills/`). Codex and Copilot share the same `.agents/skills/` output directory. Every template change needs to be generated for all hosts.
+gstack generates SKILL.md files for multiple hosts: **Claude** (`.claude/skills/`), **Codex** (`.agents/skills/`), and **Copilot** (`.agents/skills/`). Codex and Copilot share the same `.agents/skills/` output directory — only `--host codex` needs to be run during generation. Copilot-specific paths are rewritten at `setup --host copilot` time (same pattern as Kiro). Every template change needs to be generated for Claude and Codex.
 
 ### Generating for all hosts
 
@@ -239,14 +238,11 @@ gstack generates SKILL.md files for multiple hosts: **Claude** (`.claude/skills/
 # Generate Claude output (default)
 bun run gen:skill-docs
 
-# Generate Codex output
+# Generate Codex output (Copilot shares this — paths are rewritten at setup time)
 bun run gen:skill-docs --host codex
 # --host agents is an alias for --host codex
 
-# Generate Copilot output (same .agents/skills/ directory as codex)
-bun run gen:skill-docs --host copilot
-
-# Or use build, which does all three + compiles binaries
+# Or use build, which does both + compiles binaries
 bun run build
 ```
 
@@ -269,7 +265,6 @@ bun test
 # Check freshness for all hosts
 bun run gen:skill-docs --dry-run
 bun run gen:skill-docs --host codex --dry-run
-bun run gen:skill-docs --host copilot --dry-run
 
 # Health dashboard covers all hosts
 bun run skill:check
@@ -281,9 +276,9 @@ When you run `bin/dev-setup`, it creates symlinks in both `.claude/skills/` and
 
 ### Adding a new skill
 
-When you add a new skill template, both hosts get it automatically:
+When you add a new skill template, all hosts get it automatically:
 1. Create `{skill}/SKILL.md.tmpl`
-2. Run `bun run gen:skill-docs` (Claude output), `bun run gen:skill-docs --host codex` (Codex output), and `bun run gen:skill-docs --host copilot` (Copilot output)
+2. Run `bun run gen:skill-docs` (Claude output) and `bun run gen:skill-docs --host codex` (Codex output — Copilot derives from this at setup time)
 3. The dynamic template discovery picks it up — no static list to update
 4. Commit `{skill}/SKILL.md` — `.agents/` is generated at setup time and gitignored
 
diff --git a/bin/gstack-global-discover.ts b/bin/gstack-global-discover.ts
index 98ffaade6..2e1670041 100644
--- a/bin/gstack-global-discover.ts
+++ b/bin/gstack-global-discover.ts
@@ -443,36 +443,52 @@ function scanGemini(since: Date): Session[] {
 
 function scanCopilot(since: Date): Session[] {
   // GitHub Copilot CLI (standalone) stores session data in ~/.copilot/session-state/
-  const configDir = join(homedir(), ".copilot", "session-state");
-  if (!existsSync(configDir)) return [];
+  // Each session is a subdirectory: ~/.copilot/session-state/{session-id}/
+  // containing events.jsonl, workspace.yaml, and other session files.
+  const sessionStateDir = join(homedir(), ".copilot", "session-state");
+  if (!existsSync(sessionStateDir)) return [];
 
   const sessions: Session[] = [];
 
-  // Scan for conversation log files
   try {
-    const entries = readdirSync(configDir);
-    for (const entry of entries) {
-      const filePath = join(configDir, entry);
+    const sessionDirs = readdirSync(sessionStateDir);
+    for (const sessionId of sessionDirs) {
+      const sessionDir = join(sessionStateDir, sessionId);
       try {
-        const stat = statSync(filePath);
-        if (!stat.isFile() || stat.mtime < since) continue;
-        if (!entry.endsWith(".json") && !entry.endsWith(".jsonl")) continue;
-
-        // Try to extract cwd from the conversation file
-        const fd = openSync(filePath, "r");
-        const buf = Buffer.alloc(4096);
-        const bytesRead = readSync(fd, buf, 0, 4096, 0);
-        closeSync(fd);
-        const text = buf.toString("utf-8", 0, bytesRead);
-
-        // Look for cwd in JSON metadata
-        for (const line of text.split("\n").slice(0, 15)) {
-          if (!line.trim()) continue;
+        const dirStat = statSync(sessionDir);
+        if (!dirStat.isDirectory() || dirStat.mtime < since) continue;
+
+        // Look for session files within the subdirectory
+        const sessionFiles = readdirSync(sessionDir);
+        let found = false;
+
+        for (const file of sessionFiles) {
+          if (found) break;
+          const filePath = join(sessionDir, file);
           try {
-            const obj = JSON.parse(line);
-            if (obj.cwd && existsSync(obj.cwd)) {
-              sessions.push({ tool: "copilot", cwd: obj.cwd });
-              break;
+            const fileStat = statSync(filePath);
+            if (!fileStat.isFile()) continue;
+            if (!file.endsWith(".json") && !file.endsWith(".jsonl") && !file.endsWith(".yaml")) continue;
+
+            const fd = openSync(filePath, "r");
+            const buf = Buffer.alloc(4096);
+            const bytesRead = readSync(fd, buf, 0, 4096, 0);
+            closeSync(fd);
+            const text = buf.toString("utf-8", 0, bytesRead);
+
+            // Look for cwd in JSON/JSONL metadata
+            for (const line of text.split("\n").slice(0, 15)) {
+              if (!line.trim()) continue;
+              try {
+                const obj = JSON.parse(line);
+                if (obj.cwd && existsSync(obj.cwd)) {
+                  sessions.push({ tool: "copilot", cwd: obj.cwd });
+                  found = true;
+                  break;
+                }
+              } catch {
+                continue;
+              }
             }
           } catch {
             continue;
diff --git a/package.json b/package.json
index 507764d36..a7096f4f1 100644
--- a/package.json
+++ b/package.json
@@ -8,7 +8,7 @@
     "browse": "./browse/dist/browse"
   },
   "scripts": {
-    "build": "bun run gen:skill-docs && bun run gen:skill-docs --host codex && bun run gen:skill-docs --host copilot && bun build --compile browse/src/cli.ts --outfile browse/dist/browse && bun build --compile browse/src/find-browse.ts --outfile browse/dist/find-browse && bun build --compile bin/gstack-global-discover.ts --outfile bin/gstack-global-discover && bash browse/scripts/build-node-server.sh && git rev-parse HEAD > browse/dist/.version && rm -f .*.bun-build || true",
+    "build": "bun run gen:skill-docs && bun run gen:skill-docs --host codex && bun build --compile browse/src/cli.ts --outfile browse/dist/browse && bun build --compile browse/src/find-browse.ts --outfile browse/dist/find-browse && bun build --compile bin/gstack-global-discover.ts --outfile bin/gstack-global-discover && bash browse/scripts/build-node-server.sh && git rev-parse HEAD > browse/dist/.version && rm -f .*.bun-build || true",
     "gen:skill-docs": "bun run scripts/gen-skill-docs.ts",
     "dev": "bun run browse/src/cli.ts",
     "server": "bun run browse/src/server.ts",
diff --git a/scripts/skill-check.ts b/scripts/skill-check.ts
index 358a18f46..59f306c2c 100644
--- a/scripts/skill-check.ts
+++ b/scripts/skill-check.ts
@@ -163,19 +163,5 @@ try {
   console.log('      Run: bun run gen:skill-docs --host codex');
 }
 
-console.log('\n  Freshness (Copilot):');
-try {
-  execSync('bun run scripts/gen-skill-docs.ts --host copilot --dry-run', { cwd: ROOT, stdio: 'pipe' });
-  console.log('  \u2705 All Copilot generated files are fresh');
-} catch (err: any) {
-  hasErrors = true;
-  const output = err.stdout?.toString() || '';
-  console.log('  \u274c Copilot generated files are stale:');
-  for (const line of output.split('\n').filter((l: string) => l.startsWith('STALE'))) {
-    console.log(`      ${line}`);
-  }
-  console.log('      Run: bun run gen:skill-docs --host copilot');
-}
-
 console.log('');
 process.exit(hasErrors ? 1 : 0);
diff --git a/test/helpers/copilot-session-runner.ts b/test/helpers/copilot-session-runner.ts
index 99c43a360..c5013eaba 100644
--- a/test/helpers/copilot-session-runner.ts
+++ b/test/helpers/copilot-session-runner.ts
@@ -92,6 +92,18 @@ export async function runCopilotSkill(opts: {
   try {
     installSkillToTempHome(skillDir, name, tempHome);
 
+    // Copy auth config from real ~/.copilot/ so the spawned process can authenticate.
+    // Copilot CLI stores login state in ~/.copilot/config.json (or $COPILOT_HOME).
+    const realCopilotDir = process.env.COPILOT_HOME || path.join(os.homedir(), '.copilot');
+    const tempCopilotDir = path.join(tempHome, '.copilot');
+    for (const authFile of ['config.json', 'hosts.json']) {
+      const src = path.join(realCopilotDir, authFile);
+      if (fs.existsSync(src)) {
+        fs.mkdirSync(tempCopilotDir, { recursive: true });
+        fs.copyFileSync(src, path.join(tempCopilotDir, authFile));
+      }
+    }
+
     // Build copilot command
     const args = ['-p', prompt];
 

From 2df3533363500178816455f716260d0d40cbb872 Mon Sep 17 00:00:00 2001
From: Matthew Williams <williamsmat@microsoft.com>
Date: Mon, 23 Mar 2026 11:24:11 -0400
Subject: [PATCH 15/15] =?UTF-8?q?docs:=20fix=20CONTRIBUTING.md=20accuracy?=
 =?UTF-8?q?=20=E2=80=94=20remove=20Kiro=20reference,=20correct=20/codex=20?=
 =?UTF-8?q?exclusion=20reason?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- Remove '(same pattern as Kiro)' — Kiro isn't documented in CONTRIBUTING.md,
  so referencing it introduces an unexplained concept. Replaced with 'via sed'.
- Change Copilot /codex skill exclusion from 'self-referential' to 'shares
  Codex output' — Copilot ≠ Codex, so 'self-referential' is technically wrong.
  The real reason is Copilot shares Codex's generated .agents/skills/ directory.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 CONTRIBUTING.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2a8e22e39..4f43b88c2 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -230,7 +230,7 @@ To add a browse command, add it to `browse/src/commands.ts`. To add a snapshot f
 
 ## Multi-host development (Claude + Codex + Copilot)
 
-gstack generates SKILL.md files for multiple hosts: **Claude** (`.claude/skills/`), **Codex** (`.agents/skills/`), and **Copilot** (`.agents/skills/`). Codex and Copilot share the same `.agents/skills/` output directory — only `--host codex` needs to be run during generation. Copilot-specific paths are rewritten at `setup --host copilot` time (same pattern as Kiro). Every template change needs to be generated for Claude and Codex.
+gstack generates SKILL.md files for multiple hosts: **Claude** (`.claude/skills/`), **Codex** (`.agents/skills/`), and **Copilot** (`.agents/skills/`). Codex and Copilot share the same `.agents/skills/` output directory — only `--host codex` needs to be run during generation. Copilot-specific paths are rewritten at `setup --host copilot` time via sed. Every template change needs to be generated for Claude and Codex.
 
 ### Generating for all hosts
 
@@ -254,7 +254,7 @@ bun run build
 | Frontmatter | Full (name, description, allowed-tools, hooks, version) | Minimal (name + description only) | Minimal (name + description only) |
 | Paths | `~/.claude/skills/gstack` | `$GSTACK_ROOT` (`.agents/skills/gstack` in a repo, otherwise `~/.codex/skills/gstack`) | `$GSTACK_ROOT` (`.agents/skills/gstack` in a repo, otherwise `~/.copilot/skills/gstack`) |
 | Hook skills | `hooks:` frontmatter (enforced by Claude) | Inline safety advisory prose (advisory only) | Inline safety advisory prose (advisory only) |
-| `/codex` skill | Included (Claude wraps codex exec) | Excluded (self-referential) | Excluded (self-referential) |
+| `/codex` skill | Included (Claude wraps codex exec) | Excluded (self-referential) | Excluded (shares Codex output) |
 
 ### Testing Codex and Copilot output