diff --git a/src/vouch/bundle.py b/src/vouch/bundle.py
index a9e1fe4b..1723c801 100644
--- a/src/vouch/bundle.py
+++ b/src/vouch/bundle.py
@@ -28,7 +28,8 @@
 import yaml
 
 from . import audit
-from .storage import sha256_hex
+from .models import Claim, Entity, Evidence, Proposal, Relation, Session, Source
+from .storage import _deserialize_page, sha256_hex
 
 MANIFEST_NAME = "manifest.json"
 SPEC_VERSION = "vouch-bundle-0.1"
@@ -38,6 +39,17 @@
     "evidence", "sessions", "decided",
 )
 
+VALIDATORS: dict[str, Any] = {
+    "claims": lambda data: Claim.model_validate(yaml.safe_load(data)),
+    "pages": lambda data: _deserialize_page(data.decode()),
+    "sources": lambda data: Source.model_validate(yaml.safe_load(data)),
+    "entities": lambda data: Entity.model_validate(yaml.safe_load(data)),
+    "relations": lambda data: Relation.model_validate(yaml.safe_load(data)),
+    "evidence": lambda data: Evidence.model_validate(yaml.safe_load(data)),
+    "sessions": lambda data: Session.model_validate(yaml.safe_load(data)),
+    "decided": lambda data: Proposal.model_validate(yaml.safe_load(data)),
+}
+
 
 # --- export ---------------------------------------------------------------
 
@@ -163,6 +175,17 @@ class ImportCheckResult:
     issues: list[str]
 
 
+def _validate_content(path: str, data: bytes, issues: list[str]) -> None:
+    subdir = path.split("/")[0]
+    validator = VALIDATORS.get(subdir)
+    if validator is None:
+        return
+    try:
+        validator(data)
+    except Exception as e:
+        issues.append(f"schema validation failed: {path}: {e}")
+
+
 def import_check(kb_dir: Path, bundle_path: Path) -> ImportCheckResult:
     """Diff a bundle against the destination KB without writing anything."""
     new_files: list[str] = []
@@ -180,15 +203,22 @@ def import_check(kb_dir: Path, bundle_path: Path) -> ImportCheckResult:
             )
         manifest = json.loads(tar.extractfile(mf_member).read().decode())  # type: ignore[union-attr]
         bundle_id = manifest.get("bundle_id", "")
+        manifest_paths = {f["path"] for f in manifest["files"]}
         for f in manifest["files"]:
             dest = kb_dir / f["path"]
             if not dest.exists():
                 new_files.append(f["path"])
-                continue
-            if sha256_hex(dest.read_bytes()) == f["sha256"]:
+            elif sha256_hex(dest.read_bytes()) == f["sha256"]:
                 identical.append(f["path"])
             else:
                 conflicts.append(f["path"])
+        for member in tar.getmembers():
+            if member.name == MANIFEST_NAME or not member.isfile():
+                continue
+            if member.name not in manifest_paths:
+                continue
+            body = tar.extractfile(member).read()  # type: ignore[union-attr]
+            _validate_content(member.name, body, issues)
 
     return ImportCheckResult(
         ok=True, bundle_id=bundle_id,
@@ -236,7 +266,13 @@ def import_apply(
                 skipped.append(member.name)
                 continue
             dest.parent.mkdir(parents=True, exist_ok=True)
-            dest.write_bytes(tar.extractfile(member).read())  # type: ignore[union-attr]
+            body = tar.extractfile(member).read()  # type: ignore[union-attr]
+            val_issues: list[str] = []
+            _validate_content(member.name, body, val_issues)
+            if val_issues:
+                skipped.append(member.name)
+                continue
+            dest.write_bytes(body)
             written.append(member.name)
     result = {
         "bundle_id": check.bundle_id,
diff --git a/src/vouch/verify.py b/src/vouch/verify.py
index a4f10ee8..8778d7f7 100644
--- a/src/vouch/verify.py
+++ b/src/vouch/verify.py
@@ -13,7 +13,7 @@
 
 from . import audit
 from .models import Source
-from .storage import KBStore, sha256_hex
+from .storage import ArtifactNotFoundError, KBStore, sha256_hex
 
 
 @dataclass
@@ -27,7 +27,7 @@ class VerificationResult:
 def verify_source(store: KBStore, source: Source) -> VerificationResult:
     try:
         body = store.read_source_content(source.id)
-    except FileNotFoundError:
+    except ArtifactNotFoundError:
         return VerificationResult(source=source, stored_ok=False,
                                   external_status="n/a", note="stored content missing")
     stored_ok = sha256_hex(body) == source.id