diff --git a/circuitforge_core/vector/base.py b/circuitforge_core/vector/base.py
index d1c6f9b..737beaa 100644
--- a/circuitforge_core/vector/base.py
+++ b/circuitforge_core/vector/base.py
@@ -8,21 +8,16 @@ from __future__ import annotations
 
 from abc import ABC, abstractmethod
 from dataclasses import dataclass, field
-from types import MappingProxyType
-from typing import Any, Mapping
+from typing import Any
 
 
 @dataclass(frozen=True)
 class VectorMatch:
     """A single result from a vector similarity search."""
 
-    entry_id: str
+    id: str
     score: float  # lower is better (L2 / cosine distance)
-    metadata: Mapping[str, Any] = field(default_factory=dict)
-
-    def __post_init__(self) -> None:
-        if isinstance(self.metadata, dict):
-            object.__setattr__(self, "metadata", MappingProxyType(self.metadata))
+    metadata: dict[str, Any] = field(default_factory=dict)
 
 
 class VectorStore(ABC):
diff --git a/tests/test_vector/test_base.py b/tests/test_vector/test_base.py
index dfd89df..077eef4 100644
--- a/tests/test_vector/test_base.py
+++ b/tests/test_vector/test_base.py
@@ -3,7 +3,6 @@
 from __future__ import annotations
 
 from dataclasses import FrozenInstanceError
-from types import MappingProxyType
 
 import pytest
 
@@ -26,7 +25,7 @@ class _ConcreteStore(VectorStore):
         filter_metadata: dict | None = None,
     ) -> list[VectorMatch]:
         results = [
-            VectorMatch(entry_id=k, score=0.0, metadata=v[1])
+            VectorMatch(id=k, score=0.0, metadata=v[1])
             for k, v in self._data.items()
         ]
         if filter_metadata:
@@ -52,16 +51,15 @@ class _ConcreteStore(VectorStore):
 
 
 def test_vector_match_is_frozen():
-    match = VectorMatch(entry_id="a", score=0.1, metadata={})
+    match = VectorMatch(id="a", score=0.1, metadata={})
     with pytest.raises(FrozenInstanceError):
         match.score = 0.5  # type: ignore[misc]
 
 
-def test_vector_match_metadata_is_not_mutable():
-    match = VectorMatch(entry_id="a", score=0.1, metadata={"k": "v"})
-    assert isinstance(match.metadata, MappingProxyType)
-    with pytest.raises(TypeError):
-        match.metadata["k"] = "changed"  # type: ignore[index]
+def test_vector_match_metadata_is_dict():
+    match = VectorMatch(id="a", score=0.1, metadata={"k": "v"})
+    assert isinstance(match.metadata, dict)
+    assert match.metadata["k"] == "v"
 
 
 def test_upsert_and_query():
@@ -69,7 +67,7 @@ def test_upsert_and_query():
     store.upsert("chunk-1", [0.1, 0.2], {"doc_id": "book-a", "page": 1})
     results = store.query([0.1, 0.2])
     assert len(results) == 1
-    assert results[0].entry_id == "chunk-1"
+    assert results[0].id == "chunk-1"
     assert results[0].metadata["page"] == 1
 
 
@@ -79,7 +77,7 @@ def test_query_filter_metadata():
     store.upsert("c2", [0.2], {"doc_id": "book-b"})
     results = store.query([0.1], filter_metadata={"doc_id": "book-a"})
     assert len(results) == 1
-    assert results[0].entry_id == "c1"
+    assert results[0].id == "c1"
 
 
 def test_delete():