diff --git a/tools/content_build/model.py b/tools/content_build/model.py
new file mode 100644
index 0000000..4fce383
--- /dev/null
+++ b/tools/content_build/model.py
@@ -0,0 +1,76 @@
+"""Typed entries + the envelope/category rules. Pure data; no I/O. The npc
+interactive layer vs the person world-record is distinguished by id NAMESPACE
+(prefix), not by `type` (both are type 'person')."""
+
+from dataclasses import dataclass, field
+
+from .errors import BuildError
+from .parse import RawEntry
+
+CANON_TYPES = {"town", "place", "region", "faction", "person", "rule"}
+KNOWLEDGE_TYPES = {"rumor", "fact", "secret"}
+LEGAL_NAMESPACES = {"town", "place", "region", "faction", "person", "rule",
+                    "rumor", "fact", "secret", "npc"}
+STATUSES = {"candidate", "canon"}
+
+
+@dataclass
+class KnowsLink:
+    fact_id: str
+    gate: str
+
+
+@dataclass
+class Entry:
+    id: str
+    type: str
+    status: str
+    secrecy: int
+    related: list
+    body: str | None
+    source: str
+    start_disposition: str | None = None
+    knows: list = field(default_factory=list)  # list[KnowsLink]
+    disposition_notes: str | None = None
+    rungs: list | None = None
+
+    @property
+    def namespace(self) -> str:
+        return self.id.split(".", 1)[0]
+
+    @property
+    def slug(self) -> str:
+        parts = self.id.split(".", 1)
+        return parts[1] if len(parts) == 2 else parts[0]
+
+    @property
+    def is_npc_layer(self) -> bool:
+        return self.namespace == "npc"
+
+    @property
+    def is_knowledge(self) -> bool:
+        return self.type in KNOWLEDGE_TYPES
+
+    @property
+    def is_canon_entity(self) -> bool:
+        return (not self.is_npc_layer) and self.type in CANON_TYPES
+
+
+def entry_from_raw(raw: RawEntry) -> Entry:
+    d = raw.data
+    for key in ("id", "type", "status", "secrecy", "related"):
+        if key not in d:
+            raise BuildError(f"missing required field '{key}'",
+                             source=raw.source, entry_id=d.get("id", ""))
+    knows: list[KnowsLink] = []
+    for k in d.get("knows", []):
+        if "fact" not in k or "gate" not in k:
+            raise BuildError("knows entry needs 'fact' and 'gate'",
+                             source=raw.source, entry_id=d.get("id", ""))
+        knows.append(KnowsLink(fact_id=k["fact"], gate=k["gate"]))
+    return Entry(
+        id=d["id"], type=d["type"], status=d["status"], secrecy=d["secrecy"],
+        related=list(d["related"]), body=d.get("body"), source=raw.source,
+        start_disposition=d.get("start_disposition"), knows=knows,
+        disposition_notes=d.get("disposition_notes"), rungs=d.get("rungs"),
+    )
diff --git a/tools/content_build/tests/test_model.py b/tools/content_build/tests/test_model.py
new file mode 100644
index 0000000..dfcdaaf
--- /dev/null
+++ b/tools/content_build/tests/test_model.py
@@ -0,0 +1,50 @@
+import pytest
+
+from content_build.errors import BuildError
+from content_build.model import Entry, entry_from_raw
+from content_build.parse import RawEntry
+
+
+def _raw(**over) -> RawEntry:
+    data = {"id": "town.a", "type": "town", "status": "canon",
+            "secrecy": 0, "related": []}
+    data.update(over)
+    return RawEntry(data=data, source="t:1")
+
+
+def test_namespace_and_slug():
+    e = entry_from_raw(_raw(id="npc.mera-fenn", type="person",
+                            start_disposition="cold",
+                            knows=[{"fact": "rumor.x", "gate": "warm"}]))
+    assert e.namespace == "npc"
+    assert e.slug == "mera-fenn"
+
+
+def test_category_predicates():
+    npc = entry_from_raw(_raw(id="npc.t", type="person",
+                              start_disposition="cold",
+                              knows=[{"fact": "rumor.x", "gate": "warm"}]))
+    person = entry_from_raw(_raw(id="person.p", type="person"))
+    rumor = entry_from_raw(_raw(id="rumor.x", type="rumor", secrecy=1))
+    assert npc.is_npc_layer and not npc.is_canon_entity
+    assert person.is_canon_entity and not person.is_npc_layer
+    assert rumor.is_knowledge and not rumor.is_canon_entity
+
+
+def test_knows_parsed_into_links():
+    e = entry_from_raw(_raw(id="npc.t", type="person", start_disposition="cold",
+                            knows=[{"fact": "rumor.x", "gate": "neutral"}]))
+    assert e.knows[0].fact_id == "rumor.x"
+    assert e.knows[0].gate == "neutral"
+
+
+def test_missing_required_field_raises():
+    bad = RawEntry(data={"id": "town.a", "type": "town"}, source="t:1")
+    with pytest.raises(BuildError):
+        entry_from_raw(bad)
+
+
+def test_knows_missing_gate_raises():
+    with pytest.raises(BuildError):
+        entry_from_raw(_raw(id="npc.t", type="person", start_disposition="cold",
+                            knows=[{"fact": "rumor.x"}]))