git-commit-story: add init and Copilot prompt hook

ts/packages/git-commit-story/README.AUTOGEN.md

@@ -3,7 +3,7 @@
 
 <!-- AUTOGEN:DOCS:START -->
 
-<!-- AUTOGEN:DOCS:HASH:sha256=38ca35936c91b1a757a04be397408598c991864f63cf56c2d351be3a932305f5 -->
+<!-- AUTOGEN:DOCS:HASH:sha256=9a632d8aab739dcf42534ec63a8c6bb12b8b61777f38bba74c23d061a6ead9f6 -->
 <!-- AUTOGEN:DOCS:SOURCE: ./README.md (hand-written documentation; this file is the AI-generated companion) -->
 
 # git-commit-story — AI-generated documentation
@@ -30,10 +30,10 @@ External: `commander`
 
 ### Files of interest
 
-`./src/cli.ts`, `./src/tsconfig.json`.
+`./src/cli.ts`, `./src/commands/hooks.ts`, `./src/commands/init.ts`, …and 1 more under `./src/`.
 
 ---
 
-_Auto-generated against commit `464df9d8299adf53a6c3e3afd53688fbcde439f2` on `2026-09-28T20:24:26.282Z` by `docs-generate.yml`. Links validated at that commit; the working tree may have drifted by up to 24h. Re-run `pnpm --filter git-commit-story docs:verify-links` to spot-check._
+_Auto-generated against commit `031e5113b09df01a0f6392d858d93badc14699c7` on `2026-09-29T06:06:07.744Z` by `docs-generate.yml`. Links validated at that commit; the working tree may have drifted by up to 24h. Re-run `pnpm --filter git-commit-story docs:verify-links` to spot-check._
 
 <!-- AUTOGEN:DOCS:END -->

ts/packages/git-commit-story/README.md

@@ -10,10 +10,14 @@ Git runs any `git-<name>` binary on `PATH` as `git <name>`, so the
 $ cd ts/packages/git-commit-story
 $ pnpm build
 $ npm link            # puts git-commit-story on PATH
-$ git commit-story hello
-Hello from git-commit-story
+$ git commit-story init   # registers Copilot CLI hooks for this repo
+$ git commit-story hooks copilot user-prompt-submitted
+Hello World
 ```
 
+`init` writes the hooks to `.github/copilot/settings.local.json` and adds that
+file to `.git/info/exclude`, so it stays local to the clone.
+
 ## Trademarks
 
 This project may contain trademarks or logos for projects, products, or services. Authorized use of Microsoft

ts/packages/git-commit-story/src/cli.ts

@@ -5,16 +5,13 @@
 // CLI entry point. On PATH as `git-commit-story`, so git also runs it as
 // `git commit-story <command>`.
 import { Command } from "commander";
+import { hooksCommand } from "./commands/hooks.js";
+import { initCommand } from "./commands/init.js";
 
 const program = new Command("git-commit-story")
     .description("Attach agent session stories to git commits")
-    .version("0.0.1");
-
-program
-    .command("hello")
-    .description("Print a greeting")
-    .action(() => {
-        process.stdout.write("Hello from git-commit-story\n");
-    });
+    .version("0.0.1")
+    .addCommand(initCommand)
+    .addCommand(hooksCommand);
 
 program.parse();

ts/packages/git-commit-story/src/commands/hooks.ts

@@ -0,0 +1,18 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import { Command } from "commander";
+
+// `hooks`: agent hook handlers. Placeholder output until story capture exists.
+export const hooksCommand = new Command("hooks").description(
+    "Agent hook handlers",
+);
+
+hooksCommand
+    .command("copilot")
+    .description("Copilot CLI hook handlers")
+    .command("user-prompt-submitted")
+    .description("Handle the Copilot userPromptSubmitted hook")
+    .action(() => {
+        process.stdout.write("Hello World\n");
+    });

ts/packages/git-commit-story/src/commands/init.ts

@@ -0,0 +1,81 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import { Command } from "commander";
+import { execFileSync } from "node:child_process";
+import fs from "node:fs";
+import path from "node:path";
+
+// Copilot CLI reads repo-level hooks from this file. The `.local` variant is
+// per-clone, so init also adds it to `.git/info/exclude`.
+const COPILOT_SETTINGS = ".github/copilot/settings.local.json";
+const PROMPT_HOOK = "git commit-story hooks copilot user-prompt-submitted";
+
+// Recursively sorts object keys so the settings file has a stable order.
+// Array order is kept. Example: {b:1,a:{d:2,c:3}} -> {a:{c:3,d:2},b:1}.
+function sortKeys(value: unknown): unknown {
+    if (Array.isArray(value)) return value.map(sortKeys);
+    if (value === null || typeof value !== "object") return value;
+    return Object.fromEntries(
+        Object.keys(value)
+            .sort()
+            .map((k) => [k, sortKeys((value as Record<string, unknown>)[k])]),
+    );
+}
+
+// `init`: registers agent hooks for the current repository.
+export const initCommand = new Command("init")
+    .description("Register agent hooks for the current repository")
+    .action(() => {
+        const git = (...args: string[]) =>
+            execFileSync("git", args, { encoding: "utf8" }).trim();
+        const root = git("rev-parse", "--show-toplevel");
+        const settingsPath = path.join(root, COPILOT_SETTINGS);
+        let settings: {
+            hooks?: { userPromptSubmitted?: { bash?: string }[] };
+            [key: string]: unknown;
+        } = {};
+        if (fs.existsSync(settingsPath)) {
+            try {
+                settings = JSON.parse(fs.readFileSync(settingsPath, "utf8"));
+            } catch (e) {
+                process.stderr.write(
+                    `Failed to parse ${settingsPath}: ${(e as Error).message}\n`,
+                );
+                process.exitCode = 1;
+                return;
+            }
+        }
+        // Update only our hook entry; keep other keys and hooks as they are.
+        const hook = {
+            type: "command",
+            bash: PROMPT_HOOK,
+            powershell: PROMPT_HOOK,
+        };
+        settings.hooks ??= {};
+        settings.hooks.userPromptSubmitted = [
+            ...(settings.hooks.userPromptSubmitted ?? []).filter(
+                (h) => h.bash !== PROMPT_HOOK,
+            ),
+            hook,
+        ];
+        fs.mkdirSync(path.dirname(settingsPath), { recursive: true });
+        fs.writeFileSync(
+            settingsPath,
+            JSON.stringify(sortKeys(settings), null, 4) + "\n",
+        );
+
+        // `--git-path` is relative to the cwd (not the repo root), so resolve
+        // it against the cwd to work from subdirectories.
+        const exclude = path.resolve(
+            git("rev-parse", "--git-path", "info/exclude"),
+        );
+        const lines = fs.existsSync(exclude)
+            ? fs.readFileSync(exclude, "utf8").split("\n")
+            : [];
+        if (!lines.includes(COPILOT_SETTINGS)) {
+            fs.mkdirSync(path.dirname(exclude), { recursive: true });
+            fs.appendFileSync(exclude, `${COPILOT_SETTINGS}\n`);
+        }
+        process.stdout.write(`Registered Copilot hooks in ${settingsPath}\n`);
+    });