feat(mma): Implement tiered context scoping and add get_definition tool

tests/test_tiered_context.py

@@ -0,0 +1,36 @@
+import pytest
+from pathlib import Path
+from aggregate import build_tier1_context, build_tier2_context, build_tier3_context
+
+def test_build_tier1_context_exists():
+    # This should fail if the function is not defined
+    file_items = [
+        {"path": Path("conductor/product.md"), "entry": "conductor/product.md", "content": "Product content", "error": False},
+        {"path": Path("other.py"), "entry": "other.py", "content": "Other content", "error": False}
+    ]
+    history = ["User: hello", "AI: hi"]
+    
+    result = build_tier1_context(file_items, Path("."), [], history)
+    
+    assert "Product content" in result
+    # other.py should be summarized, not full content in a code block
+    assert "Other content" not in result or "Summarized" in result # Assuming summary format
+
+def test_build_tier2_context_exists():
+    file_items = [
+        {"path": Path("other.py"), "entry": "other.py", "content": "Other content", "error": False}
+    ]
+    history = ["User: hello"]
+    result = build_tier2_context(file_items, Path("."), [], history)
+    assert "Other content" in result
+
+def test_build_tier3_context_exists():
+    file_items = [
+        {"path": Path("focus.py"), "entry": "focus.py", "content": "Focus content", "error": False},
+        {"path": Path("other.py"), "entry": "other.py", "content": "Other content", "error": False}
+    ]
+    history = ["User: hello"]
+    result = build_tier3_context(file_items, Path("."), [], history, focus_files=["focus.py"])
+    
+    assert "Focus content" in result
+    assert "Other content" not in result