diff --git a/CHANGELOG.md b/CHANGELOG.md
index 448b5e4..38c29e0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -74,6 +74,11 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
   disable the recurring loop.
 
 ### Security
+- Reject non-exact integer subclasses in connection-pool count fields before
+  finite capacity is retained. Exact built-in integers and reviewed ASCII
+  decimal strings remain supported and normalize to built-in integers; callers
+  using custom integer subclasses must convert them deliberately before trusted
+  policy construction.
 - Require the request timeout policy to use the exact `EgressTimeoutPolicy` type
   during trusted construction. Timeout-policy subclasses are rejected before
   transport dispatch can dynamically invoke an overridden `as_httpcore_timeout()`,
diff --git a/docs/research/connection-pool-resource-limits.md b/docs/research/connection-pool-resource-limits.md
index 88471aa..0a825f0 100644
--- a/docs/research/connection-pool-resource-limits.md
+++ b/docs/research/connection-pool-resource-limits.md
@@ -18,6 +18,13 @@ an exact `EgressConnectionPoolPolicy` with different documented field values
 instead. This boundary does not claim EgressWeave sandboxes arbitrary Python
 code already executing inside the embedding process.
 
+Count fields accept only exact built-in integers when callers use the integer
+form; the reviewed ASCII decimal-string form remains supported and normalizes to
+exact integers, while integer subclasses are rejected before finite pool-capacity
+values are retained. This supported configuration-integrity boundary
+does not make EgressWeave a Python sandbox for arbitrary code already running in
+the host process.
+
 `max_connections` must be a positive integer or ASCII decimal string.
 `max_keepalive_connections` may be zero to retain no idle connections but must
 not exceed total capacity. `keepalive_expiry_seconds` must be a finite
diff --git a/src/egressweave/connection_pool_policy.py b/src/egressweave/connection_pool_policy.py
index f372dc7..9357460 100644
--- a/src/egressweave/connection_pool_policy.py
+++ b/src/egressweave/connection_pool_policy.py
@@ -22,7 +22,7 @@ def _normalize_connection_count(
     """Return one exact ASCII-compatible connection-count limit."""
     if isinstance(value, bool):
         raise TypeError(f"{field_name} must be an integer or ASCII decimal string")
-    if isinstance(value, int):
+    if type(value) is int:
         normalized = value
     elif isinstance(value, str):
         if not value or not value.isascii() or not value.isdecimal():
diff --git a/tests/test_connection_pool_count_value_documentation.py b/tests/test_connection_pool_count_value_documentation.py
new file mode 100644
index 0000000..fa38af4
--- /dev/null
+++ b/tests/test_connection_pool_count_value_documentation.py
@@ -0,0 +1,27 @@
+"""Documentation contracts for exact connection-pool count value types."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+REPOSITORY_ROOT = Path(__file__).resolve().parents[1]
+POOL_GUIDE_PATH = (
+    REPOSITORY_ROOT / "docs" / "research" / "connection-pool-resource-limits.md"
+)
+CHANGELOG_PATH = REPOSITORY_ROOT / "CHANGELOG.md"
+
+
+def test_connection_pool_guide_documents_exact_builtin_count_values() -> None:
+    """Keep operator guidance aligned with the primitive-value integrity boundary."""
+    guide = POOL_GUIDE_PATH.read_text(encoding="utf-8")
+
+    assert "Count fields accept only exact built-in integers" in guide
+    assert "integer subclasses are rejected" in guide
+    assert "does not make EgressWeave a Python sandbox" in guide
+
+
+def test_changelog_records_connection_count_value_sealing() -> None:
+    """Record the pre-1.0 primitive-value tightening in release history."""
+    changelog = CHANGELOG_PATH.read_text(encoding="utf-8")
+
+    assert "Reject non-exact integer subclasses in connection-pool count fields" in changelog
diff --git a/tests/test_connection_pool_count_value_types.py b/tests/test_connection_pool_count_value_types.py
new file mode 100644
index 0000000..e1a5a45
--- /dev/null
+++ b/tests/test_connection_pool_count_value_types.py
@@ -0,0 +1,41 @@
+"""Security contracts for exact connection-pool count value types."""
+
+from __future__ import annotations
+
+import pytest
+
+from egressweave import EgressConnectionPoolPolicy
+
+
+class _ConnectionCountSubclass(int):
+    """Represent an unreviewed integer subclass crossing trusted configuration."""
+
+
+@pytest.mark.parametrize(
+    "field_name",
+    ["max_connections", "max_keepalive_connections"],
+)
+def test_connection_pool_policy_rejects_integer_subclasses(field_name: str) -> None:
+    """Reject non-exact integers before retaining finite pool-capacity values."""
+    with pytest.raises(TypeError, match=field_name):
+        EgressConnectionPoolPolicy(
+            **{field_name: _ConnectionCountSubclass(1)}  # type: ignore[arg-type]
+        )
+
+
+def test_connection_pool_policy_keeps_reviewed_count_input_forms() -> None:
+    """Continue accepting exact integers and reviewed ASCII decimal strings."""
+    exact_integer = EgressConnectionPoolPolicy(
+        max_connections=8,
+        max_keepalive_connections=2,
+    )
+    decimal_string = EgressConnectionPoolPolicy(
+        max_connections="8",
+        max_keepalive_connections="2",
+    )
+
+    assert type(exact_integer.max_connections) is int
+    assert type(exact_integer.max_keepalive_connections) is int
+    assert decimal_string == exact_integer
+    assert type(decimal_string.max_connections) is int
+    assert type(decimal_string.max_keepalive_connections) is int