fix: default non-interactive init to copilot integration (#2414)

* fix: default non-interactive init integration

* chore: clarify non-interactive init default integration

* Address non-interactive init review feedback

* Fix interactive init test after fallback

README.md

@@ -485,7 +485,7 @@ specify init --here --force
 
 ![Specify CLI bootstrapping a new project in the terminal](./media/specify_cli.gif)
 
-You will be prompted to select the coding agent integration you are using. You can also proactively specify it directly in the terminal:
+In an interactive terminal, you will be prompted to select the coding agent integration you are using. In non-interactive sessions, such as CI or piped runs, `specify init` defaults to GitHub Copilot unless you pass `--integration`. You can also proactively specify the integration directly in the terminal:
 
 ```bash
 specify init <project_name> --integration copilot

docs/installation.md

@@ -41,6 +41,8 @@ uvx --from git+https://github.com/github/spec-kit.git@vX.Y.Z specify init --here
 
 ### Specify Integration
 
+Interactive terminals prompt you to choose a coding agent integration during initialization. Non-interactive sessions, such as CI or piped runs, default to GitHub Copilot unless you pass `--integration`.
+
 You can proactively specify your coding agent integration during initialization:
 
 ```bash

docs/reference/core.md

@@ -28,6 +28,8 @@ Creates a new Spec Kit project with the necessary directory structure, templates
 
 Use `<project_name>` to create a new directory, or `--here` (or `.`) to initialize in the current directory. If the directory already has files, use `--force` to merge without confirmation.
 
+When `--integration` is omitted, interactive terminals prompt you to choose an integration. Non-interactive sessions, such as CI or piped runs, default to GitHub Copilot; pass `--integration <key>` to choose a different integration explicitly.
+
 ### Examples
 
 ```bash

src/specify_cli/__init__.py

@@ -90,6 +90,7 @@ def _build_agent_config() -> dict[str, dict[str, Any]]:
     return config
 
 AGENT_CONFIG = _build_agent_config()
+DEFAULT_INIT_INTEGRATION = "copilot"
 
 AI_ASSISTANT_ALIASES = {
     "kiro": "kiro-cli",
@@ -152,6 +153,9 @@ def _build_ai_deprecation_warning(
         f"Use [bold]{replacement}[/bold] instead."
     )
 
+def _stdin_is_interactive() -> bool:
+    return sys.stdin.isatty()
+
 SCRIPT_TYPE_CHOICES = {"sh": "POSIX Shell (bash/zsh)", "ps": "PowerShell"}
 
 CLAUDE_LOCAL_PATH = Path.home() / ".claude" / "local" / "claude"
@@ -995,7 +999,8 @@ def init(
 
     This command will:
     1. Check that required tools are installed (git is optional)
-    2. Let you choose your coding agent integration
+    2. Let you choose your coding agent integration, or default to Copilot
+       in non-interactive sessions
     3. Download template from GitHub (or use bundled assets with --offline)
     4. Initialize a fresh git repository (if not --no-git and no existing repo)
     5. Optionally set up coding agent integration commands
@@ -1162,13 +1167,19 @@ def init(
             console.print(f"[red]Error:[/red] Invalid AI assistant '{ai_assistant}'. Choose from: {', '.join(AGENT_CONFIG.keys())}")
             raise typer.Exit(1)
         selected_ai = ai_assistant
+    elif not _stdin_is_interactive():
+        console.print(
+            f"[dim]Non-interactive session detected: defaulting to '{DEFAULT_INIT_INTEGRATION}'. "
+            "Use --integration to choose a different agent.[/dim]"
+        )
+        selected_ai = DEFAULT_INIT_INTEGRATION
     else:
         # Create options dict for selection (agent_key: display_name)
         ai_choices = {key: config["name"] for key, config in AGENT_CONFIG.items()}
         selected_ai = select_with_arrows(
             ai_choices,
             "Choose your coding agent integration:",
-            "copilot"
+            DEFAULT_INIT_INTEGRATION,
         )
 
     # Auto-promote interactively selected agents to the integration path
@@ -1233,7 +1244,7 @@ def init(
     else:
         default_script = "ps" if os.name == "nt" else "sh"
 
-        if sys.stdin.isatty():
+        if _stdin_is_interactive():
             selected_script = select_with_arrows(SCRIPT_TYPE_CHOICES, "Choose script type (or press Enter)", default_script)
         else:
             selected_script = default_script

tests/integrations/test_cli.py

@@ -81,6 +81,29 @@ class TestInitIntegrationFlag:
         shared_manifest = project / ".specify" / "integrations" / "speckit.manifest.json"
         assert shared_manifest.exists()
 
+    def test_noninteractive_init_defaults_to_copilot(self, tmp_path, monkeypatch):
+        from typer.testing import CliRunner
+        from specify_cli import app
+        import specify_cli
+
+        def fail_select(*_args, **_kwargs):
+            raise AssertionError("non-interactive init should not open the integration picker")
+
+        monkeypatch.setattr(specify_cli, "select_with_arrows", fail_select)
+
+        runner = CliRunner()
+        project = tmp_path / "noninteractive"
+        result = runner.invoke(app, [
+            "init", str(project), "--script", "sh", "--no-git", "--ignore-agent-tools",
+        ], catch_exceptions=False)
+
+        assert result.exit_code == 0, result.output
+        assert f"defaulting to '{specify_cli.DEFAULT_INIT_INTEGRATION}'" in result.output
+        assert (project / ".github" / "agents" / "speckit.plan.agent.md").exists()
+
+        data = json.loads((project / ".specify" / "integration.json").read_text(encoding="utf-8"))
+        assert data["integration"] == specify_cli.DEFAULT_INIT_INTEGRATION
+
     def test_ai_copilot_auto_promotes(self, tmp_path):
         from typer.testing import CliRunner
         from specify_cli import app

tests/integrations/test_integration_claude.py

@@ -196,7 +196,10 @@ class TestClaudeIntegration:
         try:
             os.chdir(project)
             runner = CliRunner()
-            with patch("specify_cli.select_with_arrows", return_value="claude"):
+            with (
+                patch("specify_cli._stdin_is_interactive", return_value=True),
+                patch("specify_cli.select_with_arrows", return_value="claude"),
+            ):
                 result = runner.invoke(
                     app,
                     [