test+docs(game_eval): address self-review findings on #518

- Move the no-session test's skip-guard BEFORE _send_eval. The old guard
  checked conn.captured AFTER the call, so if a session were ever present
  on the bare plugin, _send_eval would already have armed timers and sent
  a real mcp:eval into the running game before the test could bail.
  Gate on _first_active_session() up front instead (precondition, not
  post-hoc) so the test can never have side effects.
- tools/editor.py: note EVAL_GAME_NOT_READY also covers a missing/disabled
  _mcp_game_helper autoload, not just "still launching" -- matches the
  fuller handlers/editor.py wording so an LLM caller doesn't retry forever
  when the real fix is enabling the autoload.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: dsarno

src/godot_ai/tools/editor.py

@@ -39,8 +39,9 @@
         'await' so user code can await internally. Errors return fast and
         actionable: EVAL_COMPILE_ERROR for a syntax/parse error,
         EVAL_RUNTIME_ERROR (with the real message + line) for a runtime
-        error; EVAL_GAME_NOT_READY if the game is still launching (retry
-        once it's up); a genuine infinite loop / never-firing await still
+        error; EVAL_GAME_NOT_READY if the game isn't ready yet — still
+        launching (retry once it's up) or the _mcp_game_helper autoload is
+        missing/disabled; a genuine infinite loop / never-firing await still
         times out. 'await' only progresses while the game window is focused."""
 
 

test_project/tests/test_game_eval_errors.gd

@@ -406,14 +406,16 @@ func test_send_eval_without_active_session_replies_game_not_ready() -> void:
 		skip("No SceneTree available")
 		return
 	var plugin := McpDebuggerPlugin.new()
-	var conn := _StubConnection.new()
-	plugin._send_eval(tree, "return 1", "rid-no-session", conn, 10.0)
-	if conn.captured.is_empty():
-		## A live debugger session is present (e.g. a game running under this
-		## editor), so the no-session branch wasn't exercised — don't false-fail.
-		conn.free()
+	## Gate BEFORE calling _send_eval: a bare plugin normally has no session, but
+	## if one were present _send_eval would take its live path (arm timers, send a
+	## real mcp:eval into the running game). Skip first so the test never has side
+	## effects in that case rather than bailing after the fact.
+	if plugin._first_active_session() != null:
 		skip("an active debugger session is present; no-session branch not exercised")
 		return
+	var conn := _StubConnection.new()
+	plugin._send_eval(tree, "return 1", "rid-no-session", conn, 10.0)
+	assert_eq(conn.captured.size(), 1, "exactly one deferred reply is sent")
 	assert_eq(conn.captured[0]["payload"]["error"]["code"], ErrorCodes.EVAL_GAME_NOT_READY,
 		"no active debugger session replies with EVAL_GAME_NOT_READY, not INTERNAL_ERROR")
 	conn.free()