feat: seed a default global SOUL.md

Seed ~/.hermes/SOUL.md when missing, load SOUL only from HERMES_HOME, and inject raw SOUL content without wrapper text. If the file exists but is empty, nothing is added to the system prompt.

tests/agent/test_prompt_builder.py

@@ -349,14 +349,15 @@ class TestBuildSkillsSystemPrompt:
 
 
 class TestBuildContextFilesPrompt:
-    def test_empty_dir_returns_empty(self, tmp_path):
+    def test_empty_dir_loads_seeded_global_soul(self, tmp_path):
         from unittest.mock import patch
 
         fake_home = tmp_path / "fake_home"
         fake_home.mkdir()
         with patch("pathlib.Path.home", return_value=fake_home):
             result = build_context_files_prompt(cwd=str(tmp_path))
-        assert result == ""
+        assert "Project Context" in result
+        assert "# Hermes ☤" in result
 
     def test_loads_agents_md(self, tmp_path):
         (tmp_path / "AGENTS.md").write_text("Use Ruff for linting.")
@@ -369,11 +370,33 @@ class TestBuildContextFilesPrompt:
         result = build_context_files_prompt(cwd=str(tmp_path))
         assert "type hints" in result
 
-    def test_loads_soul_md(self, tmp_path):
-        (tmp_path / "SOUL.md").write_text("Be concise and friendly.")
+    def test_loads_soul_md_from_hermes_home_only(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_home"))
+        hermes_home = tmp_path / "hermes_home"
+        hermes_home.mkdir()
+        (hermes_home / "SOUL.md").write_text("Be concise and friendly.", encoding="utf-8")
+        (tmp_path / "SOUL.md").write_text("cwd soul should be ignored", encoding="utf-8")
         result = build_context_files_prompt(cwd=str(tmp_path))
-        assert "concise and friendly" in result
-        assert "SOUL.md" in result
+        assert "Be concise and friendly." in result
+        assert "cwd soul should be ignored" not in result
+
+    def test_soul_md_has_no_wrapper_text(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_home"))
+        hermes_home = tmp_path / "hermes_home"
+        hermes_home.mkdir()
+        (hermes_home / "SOUL.md").write_text("Be concise and friendly.", encoding="utf-8")
+        result = build_context_files_prompt(cwd=str(tmp_path))
+        assert "Be concise and friendly." in result
+        assert "If SOUL.md is present" not in result
+        assert "## SOUL.md" not in result
+
+    def test_empty_soul_md_adds_nothing(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_home"))
+        hermes_home = tmp_path / "hermes_home"
+        hermes_home.mkdir()
+        (hermes_home / "SOUL.md").write_text("\n\n", encoding="utf-8")
+        result = build_context_files_prompt(cwd=str(tmp_path))
+        assert result == ""
 
     def test_blocks_injection_in_agents_md(self, tmp_path):
         (tmp_path / "AGENTS.md").write_text(