fix: protect nit private state

Author: stainlu

.gitignore

@@ -1,5 +1,6 @@
 node_modules/
 dist/
+.nit/
 .DS_Store
 *.log
 CLAUDE.md

SKILL.md

@@ -2,7 +2,7 @@
 name: nit
 description: Git for agent identity — one identity, any apps
 metadata:
-  version: 0.6.32
+  version: 0.6.33
 ---
 
 # nit — Git for Agent Identity

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@newtype-ai/nit",
-  "version": "0.6.32",
+  "version": "0.6.33",
   "description": "Version control for agent cards",
   "type": "module",
   "bin": {

package.json

@@ -175,6 +175,8 @@ export type { MachineIdRuntime } from './fingerprint.js';
 
 const NIT_DIR = '.nit';
 const CARD_FILE = 'agent-card.json';
+const GITIGNORE_FILE = '.gitignore';
+const NIT_GITIGNORE_ENTRY = '.nit/';
 const DEFAULT_API_BASE = 'https://api.newtype-ai.org';
 const CURRENT_PROTOCOL_VERSION = '0.3.0';
 const BASE64_RE = /^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/;
@@ -301,6 +303,31 @@ async function writeWorkingCard(
   await fs.writeFile(cardPath, JSON.stringify(card, null, 2) + '\n', 'utf-8');
 }
 
+function gitignoreCoversNit(raw: string): boolean {
+  return raw.split(/\r?\n/).some((line) => {
+    const trimmed = line.trim();
+    if (!trimmed || trimmed.startsWith('#')) return false;
+    return trimmed === '.nit' || trimmed === '.nit/' || trimmed === '/.nit' || trimmed === '/.nit/';
+  });
+}
+
+async function ensureNitGitignored(projDir: string): Promise<void> {
+  const gitignorePath = join(projDir, GITIGNORE_FILE);
+  let raw = '';
+  try {
+    raw = await fs.readFile(gitignorePath, 'utf-8');
+  } catch (err) {
+    const code = (err as NodeJS.ErrnoException).code;
+    if (code !== 'ENOENT') throw err;
+    await fs.writeFile(gitignorePath, `${NIT_GITIGNORE_ENTRY}\n`, 'utf-8');
+    return;
+  }
+
+  if (gitignoreCoversNit(raw)) return;
+  const separator = raw.length === 0 || raw.endsWith('\n') ? '' : '\n';
+  await fs.writeFile(gitignorePath, `${raw}${separator}${NIT_GITIGNORE_ENTRY}\n`, 'utf-8');
+}
+
 /**
  * Get the card stored at a specific commit.
  */
@@ -431,6 +458,8 @@ export async function init(options?: {
     discoveredSkills = await discoverProjectSkills(projDir);
   }
 
+  await ensureNitGitignored(projDir);
+
   // Create directory structure
   await fs.mkdir(join(nitDir, 'objects'), { recursive: true });
   await fs.mkdir(join(nitDir, 'refs', 'heads'), { recursive: true });

src/index.ts

@@ -394,6 +394,7 @@ test('init fails without overwriting malformed existing agent-card.json', () =>
   assert.match(result.stderr, /Invalid agent-card\.json/);
   assert.equal(readFileSync(cardPath, 'utf8'), '{bad json');
   assert.equal(existsSync(join(cwd, '.nit')), false);
+  assert.equal(existsSync(join(cwd, '.gitignore')), false);
 });
 
 test('init fails before creating .nit when existing card lacks required fields', () => {
@@ -405,6 +406,7 @@ test('init fails before creating .nit when existing card lacks required fields',
   assert.notEqual(result.status, 0);
   assert.match(result.stderr, /missing "name"/);
   assert.equal(existsSync(join(cwd, '.nit')), false);
+  assert.equal(existsSync(join(cwd, '.gitignore')), false);
 });
 
 test('init rejects malformed skill entries before creating .nit', () => {
@@ -420,6 +422,37 @@ test('init rejects malformed skill entries before creating .nit', () => {
   assert.notEqual(result.status, 0);
   assert.match(result.stderr, /skills\[0\] must be a JSON object/);
   assert.equal(existsSync(join(cwd, '.nit')), false);
+  assert.equal(existsSync(join(cwd, '.gitignore')), false);
+});
+
+test('init creates .gitignore entry for private nit state', () => {
+  const cwd = workspace('nit-init-gitignore-');
+  initWorkspace(cwd);
+
+  const gitignore = readFileSync(join(cwd, '.gitignore'), 'utf8');
+  assert.match(gitignore, /^\.nit\/$/m);
+});
+
+test('init appends .nit to existing .gitignore exactly once', () => {
+  const cwd = workspace('nit-init-gitignore-existing-');
+  writeFileSync(join(cwd, '.gitignore'), 'node_modules/\n.DS_Store', 'utf8');
+
+  initWorkspace(cwd);
+
+  const gitignore = readFileSync(join(cwd, '.gitignore'), 'utf8');
+  assert.match(gitignore, /^node_modules\//);
+  assert.match(gitignore, /\.DS_Store\n\.nit\/\n$/);
+  assert.equal((gitignore.match(/^\.nit\/$/gm) ?? []).length, 1);
+});
+
+test('init respects existing .nit ignore variants without duplicating', () => {
+  const cwd = workspace('nit-init-gitignore-existing-nit-');
+  writeFileSync(join(cwd, '.gitignore'), '# local\n/.nit/\n', 'utf8');
+
+  initWorkspace(cwd);
+
+  const gitignore = readFileSync(join(cwd, '.gitignore'), 'utf8');
+  assert.equal(gitignore, '# local\n/.nit/\n');
 });
 
 test('checkout fails closed when working card is malformed', () => {