Add llms.txt to repo root for AI tool discoverability

Makefile

@@ -1040,6 +1040,11 @@ generate-schema-docs:
 generate-agent-factory:
 	node scripts/generate-agent-factory.js
 
+# Generate llms.txt at repository root from .github/aw/*.md
+.PHONY: generate-llms-txt
+generate-llms-txt:
+	node scripts/generate-llms-txt.js
+
 # Build slides with Marp
 .PHONY: build-slides
 build-slides:
@@ -1217,7 +1222,7 @@ sbom:
 
 # Agent should run this task before finishing its turns
 .PHONY: agent-finish
-agent-finish: deps-dev fmt lint build build-wasm test-all validate-otel-contract fix recompile dependabot generate-schema-docs generate-agent-factory security-scan
+agent-finish: deps-dev fmt lint build build-wasm test-all validate-otel-contract fix recompile dependabot generate-schema-docs generate-agent-factory generate-llms-txt security-scan
 	@echo "Agent finished tasks successfully."
 
 # Fast pre-PR gate — run before every intermediate report_progress call.
@@ -1322,6 +1327,7 @@ help:
 	@echo "  dependabot       - Generate Dependabot manifests for npm dependencies in workflows"
 	@echo "  generate-schema-docs - Generate frontmatter full reference documentation from JSON schema"
 	@echo "  generate-agent-factory     - Generate agent factory documentation page"
+	@echo "  generate-llms-txt  - Generate llms.txt at repository root from .github/aw/*.md"
 	@echo "  build-slides     - Build slides with Marp to docs/public/slides/gh-aw.html"
 	@echo "  deps-docs        - Install Astro documentation dependencies"
 	@echo "  build-docs       - Build Astro documentation to docs/dist"

scripts/generate-llms-txt.js

@@ -0,0 +1,63 @@
+#!/usr/bin/env node
+
+/**
+ * llms.txt Generator
+ *
+ * Generates llms.txt at the repository root from the agent prompt files in
+ * .github/aw/*.md. Mirrors the logic in docs/src/pages/llms.txt.ts so that
+ * https://github.com/<org>/gh-aw/llms.txt resolves to the same content that
+ * the docs site serves at /llms.txt.
+ *
+ * Usage:
+ *   node scripts/generate-llms-txt.js
+ */
+
+import fs from "fs";
+import path from "path";
+import { fileURLToPath } from "url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const ROOT = path.resolve(__dirname, "..");
+const AW_DIR = path.join(ROOT, ".github", "aw");
+const OUT_FILE = path.join(ROOT, "llms.txt");
+const RAW_BASE = "https://raw.githubusercontent.com/github/gh-aw/main/.github/aw";
+
+function parseFrontmatterDescription(content) {
+  const match = content.match(/^---[\r\n]+([\s\S]*?)[\r\n]+---/);
+  if (!match) return "";
+  const descMatch = match[1].match(/^description:\s*(.+)$/m);
+  return descMatch ? descMatch[1].trim() : "";
+}
+
+const files = fs
+  .readdirSync(AW_DIR)
+  .filter(f => f.endsWith(".md"))
+  .sort();
+
+const prompts = files.map(file => {
+  const content = fs.readFileSync(path.join(AW_DIR, file), "utf-8");
+  return {
+    file,
+    description: parseFrontmatterDescription(content),
+    rawUrl: `${RAW_BASE}/${file}`,
+  };
+});
+
+const lines = [
+  "# GitHub Agentic Workflows",
+  "",
+  "> Agent-optimised prompt files for GitHub Agentic Workflows (gh-aw).",
+  "> These markdown files are designed for AI agents and LLMs, not human readers.",
+  "",
+  "## Agent Prompts",
+  "",
+  ...prompts.map(({ file, description, rawUrl }) => {
+    const label = file.replace(/\.md$/, "");
+    return description ? `- [${label}](${rawUrl}): ${description}` : `- [${label}](${rawUrl})`;
+  }),
+];
+
+fs.writeFileSync(OUT_FILE, lines.join("\n") + "\n", "utf-8");
+console.log(`Written ${OUT_FILE} (${prompts.length} prompts)`);