diff --git a/schemas/aep/evidence-envelope.schema.json b/schemas/aep/evidence-envelope.schema.json
index 227648e..5e8112a 100644
--- a/schemas/aep/evidence-envelope.schema.json
+++ b/schemas/aep/evidence-envelope.schema.json
@@ -2,7 +2,7 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://wasmagent.dev/schemas/aep/evidence-envelope.schema.json",
   "title": "EvidenceEnvelope",
-  "description": "Shared base fields for all AEP evidence records \u2014 schema_version, trace_id, created_at_ms, and optional signature. Every evidence type $refs this schema for its envelope fields.",
+  "description": "Shared base fields for all AEP evidence records — schema_version, trace_id, created_at_ms, and optional signature. Every evidence type $refs this schema for its envelope fields.",
   "type": "object",
   "required": [
     "schema_version",
@@ -23,27 +23,18 @@
     },
     "signature": {
       "type": "object",
-      "description": "Optional tamper-evident signature over the record content",
       "required": [
         "alg",
         "key_id",
         "sig"
       ],
       "properties": {
-        "alg": {
-          "type": "string",
-          "description": "Signature algorithm, e.g. ed25519"
-        },
-        "key_id": {
-          "type": "string",
-          "description": "Identifier of the signing key"
-        },
-        "sig": {
-          "type": "string",
-          "description": "Base64-encoded signature bytes"
-        }
-      },
-      "additionalProperties": false
+        "alg": { "type": "string" },
+        "key_id": { "type": "string" },
+        "sig": { "type": "string" },
+        "bundle": { "type": "object" },
+        "transparency_log_ref": { "type": "string" }
+      }
     }
   }
 }
diff --git a/src/wasmagent_protocol/__init__.py b/src/wasmagent_protocol/__init__.py
index c67435a..6c8d41d 100644
--- a/src/wasmagent_protocol/__init__.py
+++ b/src/wasmagent_protocol/__init__.py
@@ -24,10 +24,17 @@
 
 def _read(rel_path: str) -> str:
     # rel_path is e.g. "index.json" or "aep/aep-record.schema.json"
-    resource = resources.files(_SCHEMAS_PKG)
-    for part in rel_path.split("/"):
-        resource = resource / part
-    return resource.read_text(encoding="utf-8")
+    try:
+        resource = resources.files(_SCHEMAS_PKG)
+        for part in rel_path.split("/"):
+            resource = resource / part
+        return resource.read_text(encoding="utf-8")
+    except (ModuleNotFoundError, TypeError, FileNotFoundError):
+        schemas_dir = Path(__file__).resolve().parent.parent.parent / "schemas"
+        p = schemas_dir
+        for part in rel_path.split("/"):
+            p = p / part
+        return p.read_text(encoding="utf-8")
 
 
 INDEX: dict[str, Any] = json.loads(_read("index.json"))
@@ -69,8 +76,15 @@ def schema_path(schema_id: str) -> Path:
         raise KeyError(
             f"unknown schema id {schema_id!r}; known: {', '.join(_PATHS)}"
         ) from None
-    resource = resources.files(_SCHEMAS_PKG)
-    for part in rel.split("/"):
-        resource = resource / part
-    with resources.as_file(resource) as p:
-        return Path(p)
+    try:
+        resource = resources.files(_SCHEMAS_PKG)
+        for part in rel.split("/"):
+            resource = resource / part
+        with resources.as_file(resource) as p:
+            return Path(p)
+    except (ModuleNotFoundError, TypeError, FileNotFoundError):
+        schemas_dir = Path(__file__).resolve().parent.parent.parent / "schemas"
+        p = schemas_dir
+        for part in rel.split("/"):
+            p = p / part
+        return p
diff --git a/tests/test_conformance.py b/tests/test_conformance.py
new file mode 100644
index 0000000..f0c15a3
--- /dev/null
+++ b/tests/test_conformance.py
@@ -0,0 +1,53 @@
+"""Pytest entry for the conformance harness.
+
+`tests/conformance.py` is a runnable script (`python3 tests/conformance.py`)
+with a ``main()`` but no ``test_*`` functions, so ``pytest tests/`` collects
+nothing from it directly. This module surfaces that harness as a single pytest
+test so the bot/CI pytest gate actually exercises the schema + fixture
+invariants — the same checks documented in CLAUDE.md.
+"""
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+# tests/ is not a package; make conformance.py importable whether pytest runs
+# from the repo root or collects this file directly.
+_HERE = Path(__file__).resolve().parent
+if str(_HERE) not in sys.path:
+    sys.path.insert(0, str(_HERE))
+
+import conformance  # noqa: E402
+
+
+def test_conformance_harness() -> None:
+    """Every registered schema is well-formed, $refs resolve, and fixtures
+    pass/fail as expected. Mirrors ``python3 tests/conformance.py``'s exit code.
+    """
+    conformance.errors.clear()
+    rc = conformance.main()
+    assert rc == 0, (
+        "conformance harness reported failures:\n"
+        + "\n".join(f"  - {e}" for e in conformance.errors)
+    )
+
+
+def test_evidence_envelope_schema() -> None:
+    """Verify evidence-envelope schema registration, canonical $id, and signature shape."""
+    import wasmagent_protocol
+
+    assert "evidence-envelope" in wasmagent_protocol.schema_ids()
+    envelope = wasmagent_protocol.get_schema("evidence-envelope")
+    assert envelope["$id"] == "https://wasmagent.dev/schemas/aep/evidence-envelope.schema.json"
+    assert envelope["title"] == "EvidenceEnvelope"
+    assert set(envelope["required"]) == {"schema_version", "created_at_ms"}
+
+    # Signature field properties must match aep-record signature fields
+    aep_record = wasmagent_protocol.get_schema("aep-record")
+    env_sig = envelope["properties"]["signature"]
+    aep_sig = aep_record["properties"]["signature"]
+
+    assert set(env_sig["required"]) == set(aep_sig["required"])
+    assert set(env_sig["properties"].keys()) == set(aep_sig["properties"].keys())
+    assert env_sig["properties"]["bundle"] == aep_sig["properties"]["bundle"]
+