diff --git a/.changeset/clear-boats-rhyme.md b/.changeset/clear-boats-rhyme.md
new file mode 100644
index 000000000..b8c67fc3a
--- /dev/null
+++ b/.changeset/clear-boats-rhyme.md
@@ -0,0 +1,5 @@
+---
+"@nanocollective/nanocoder": minor
+---
+
+Added support for a .nanocoderignore file, letting you hide tracked-but-unwanted files (lockfiles, .env, generated fixtures) from the AI even when .gitignore doesn't cover them. Thanks to @A-S-Manoj. Closes #755.
diff --git a/docs/features/file-explorer.md b/docs/features/file-explorer.md
index 02f2e7acb..f8b80157a 100644
--- a/docs/features/file-explorer.md
+++ b/docs/features/file-explorer.md
@@ -78,3 +78,5 @@ Sometimes you want to browse your project and pick files visually rather than ty
 ```
 
 The explorer respects your `.gitignore`, so you won't see `node_modules`, `dist`, or other ignored directories.
+
+It also respects an optional `.nanocoderignore`. Use this for files that are tracked in git (and so aren't covered by `.gitignore`) but that you don't want the AI to read (large lockfiles like `package-lock.json`, generated fixtures, or sensitive files like `.env`). Patterns in `.nanocoderignore` use the same syntax as `.gitignore`.
diff --git a/source/utils/gitignore-loader.spec.ts b/source/utils/gitignore-loader.spec.ts
index 6c0e2d478..4197bda1a 100644
--- a/source/utils/gitignore-loader.spec.ts
+++ b/source/utils/gitignore-loader.spec.ts
@@ -84,6 +84,65 @@ test.serial('loadGitignore works without .gitignore file', async t => {
 	}
 });
 
+test.serial('loadGitignore loads .nanocoderignore patterns', async t => {
+	const testDir = join(process.cwd(), 'test-nanocoderignore-temp');
+
+	try {
+		mkdirSync(testDir, {recursive: true});
+		writeFileSync(join(testDir, '.nanocoderignore'), '*.secret\ndata/\n');
+
+		const ig = loadGitignore(testDir);
+
+		t.true(ig.ignores('api.secret'), 'Should ignore .secret files');
+		t.true(ig.ignores('data/dump.csv'), 'Should ignore data/ directory');
+		t.false(ig.ignores('file.ts'), 'Should not ignore unrelated files');
+	} finally {
+		rmSync(testDir, {recursive: true, force: true});
+	}
+});
+
+test.serial(
+	'loadGitignore merges .gitignore and .nanocoderignore patterns',
+	async t => {
+		const testDir = join(process.cwd(), 'test-both-ignores-temp');
+
+		try {
+			mkdirSync(testDir, {recursive: true});
+			writeFileSync(join(testDir, '.gitignore'), '*.log\n');
+			writeFileSync(join(testDir, '.nanocoderignore'), '.env\npackage-lock.json\n');
+
+			const ig = loadGitignore(testDir);
+
+			t.true(ig.ignores('file.log'), 'Should ignore .gitignore patterns');
+			t.true(ig.ignores('.env'), 'Should ignore .nanocoderignore patterns');
+			t.true(
+				ig.ignores('package-lock.json'),
+				'Should ignore committed files listed in .nanocoderignore',
+			);
+			t.false(ig.ignores('file.ts'), 'Should not ignore unrelated files');
+		} finally {
+			rmSync(testDir, {recursive: true, force: true});
+		}
+	},
+);
+
+test.serial('loadGitignore works without .nanocoderignore file', async t => {
+	const testDir = join(process.cwd(), 'test-no-nanocoderignore-temp');
+
+	try {
+		mkdirSync(testDir, {recursive: true});
+		// No .nanocoderignore file
+
+		const ig = loadGitignore(testDir);
+
+		// Should still have default ignores and not throw
+		t.true(ig.ignores('node_modules/file.js'));
+		t.false(ig.ignores('src/file.ts'));
+	} finally {
+		rmSync(testDir, {recursive: true, force: true});
+	}
+});
+
 test('loadGitignore ignores all language-specific directories', t => {
 	const ig = loadGitignore(process.cwd());
 
diff --git a/source/utils/gitignore-loader.ts b/source/utils/gitignore-loader.ts
index 40bfe9e24..866aa2cb1 100644
--- a/source/utils/gitignore-loader.ts
+++ b/source/utils/gitignore-loader.ts
@@ -38,15 +38,22 @@ const DEFAULT_IGNORE_DIRS = [
 ];
 
 /**
- * Load and parse .gitignore file, returns an ignore instance.
+ * Load and parse .gitignore and .nanocoderignore files, returns an ignore instance.
  * Always includes default ignore patterns for common directories.
  *
- * @param cwd - The current working directory to load .gitignore from
+ * .nanocoderignore is an additional, nanocoder-specific ignore file. It is useful
+ * for hiding files from the AI (to save tokens / avoid context bloat) even when
+ * those files are tracked in git and therefore not covered by .gitignore
+ * (e.g. package-lock.json, large fixtures, or sensitive files like .env that are
+ * intentionally committed).
+ *
+ * @param cwd - The current working directory to load .gitignore / .nanocoderignore from
  * @returns An ignore instance configured with patterns
  */
 export function loadGitignore(cwd: string): ReturnType<typeof ignore> {
 	const ig = ignore();
 	const gitignorePath = join(cwd, '.gitignore');
+	const nanocoderignorePath = join(cwd, '.nanocoderignore');
 
 	// Always ignore common directories
 	ig.add(DEFAULT_IGNORE_DIRS);
@@ -62,6 +69,18 @@ export function loadGitignore(cwd: string): ReturnType<typeof ignore> {
 		}
 	}
 
+	// Load .nanocoderignore if it exists. Patterns are additive on top of
+	// .gitignore and the default ignores, not a replacement for them.
+	if (existsSync(nanocoderignorePath)) {
+		try {
+			const nanocoderignoreContent = readFileSync(nanocoderignorePath, 'utf-8');
+			ig.add(nanocoderignoreContent);
+		} catch {
+			// Silently fail if we can't read .nanocoderignore
+			// The gitignore + hardcoded ignores above will still apply
+		}
+	}
+
 	return ig;
 }