Implemented the next missing parity slice around agent configurations.

tests/test_agent_registry.py

@@ -6,7 +6,14 @@ import unittest
 from pathlib import Path
 from unittest.mock import patch
 
-from src.agent_registry import load_agent_registry, render_agent_detail, render_agents_report
+from src.agent_registry import (
+    create_agent_definition,
+    delete_agent_definition,
+    load_agent_registry,
+    render_agent_detail,
+    render_agents_report,
+    update_agent_definition,
+)
 
 
 def _write_agent(path: Path, *, name: str, description: str, body: str, extra: str = '') -> None:
@@ -22,6 +29,50 @@ def _write_agent(path: Path, *, name: str, description: str, body: str, extra: s
 
 
 class AgentRegistryTests(unittest.TestCase):
+    def test_create_update_delete_agent_definition_roundtrip(self) -> None:
+        with tempfile.TemporaryDirectory() as home_dir, tempfile.TemporaryDirectory() as tmp_dir:
+            workspace = Path(tmp_dir)
+            with patch.dict(os.environ, {'HOME': home_dir}):
+                created = create_agent_definition(
+                    workspace,
+                    agent_type='reviewer',
+                    description='Review implementation changes.',
+                    system_prompt='Inspect diffs and summarize risks.',
+                    source='project',
+                    tools=('read_file', 'grep_search'),
+                    model='demo-model',
+                    initial_prompt='Start with changed files.',
+                )
+                self.assertEqual(created.action, 'created')
+                self.assertTrue(Path(created.file_path).exists())
+
+                snapshot = load_agent_registry(workspace)
+                detail = render_agent_detail(snapshot, 'reviewer')
+                self.assertIn('demo-model', detail)
+                self.assertIn('Start with changed files.', detail)
+
+                updated = update_agent_definition(
+                    workspace,
+                    agent_type='reviewer',
+                    description='Review code and tests carefully.',
+                    system_prompt='Focus on regressions and missing coverage.',
+                    source='project',
+                )
+                self.assertEqual(updated.action, 'updated')
+
+                snapshot = load_agent_registry(workspace)
+                detail = render_agent_detail(snapshot, 'reviewer')
+                self.assertIn('Review code and tests carefully.', detail)
+                self.assertIn('Focus on regressions and missing coverage.', detail)
+
+                deleted = delete_agent_definition(
+                    workspace,
+                    agent_type='reviewer',
+                    source='project',
+                )
+                self.assertEqual(deleted.action, 'deleted')
+                self.assertFalse(Path(deleted.file_path).exists())
+
     def test_project_agent_overrides_built_in_agent(self) -> None:
         with tempfile.TemporaryDirectory() as home_dir, tempfile.TemporaryDirectory() as tmp_dir:
             workspace = Path(tmp_dir)