diff --git a/backend/app/schemas/knowledge.py b/backend/app/schemas/knowledge.py
new file mode 100644
index 0000000..1c4e211
--- /dev/null
+++ b/backend/app/schemas/knowledge.py
@@ -0,0 +1,34 @@
+"""Knowledge base schemas."""
+from pydantic import BaseModel, Field
+from typing import Optional, List
+from datetime import datetime
+
+
+class KnowledgeCreate(BaseModel):
+    title: str = Field(..., min_length=1, max_length=500)
+    content: str = ""
+    doc_type: str = "text"
+    source: str = ""
+    tags: str = ""
+    project_id: Optional[int] = None
+
+
+class KnowledgeResponse(BaseModel):
+    id: int
+    project_id: Optional[int] = None
+    title: str
+    content: str
+    doc_type: str
+    source: str
+    tags: str
+    tenant_id: int
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class KnowledgeSearchResult(BaseModel):
+    doc_id: int
+    title: str
+    snippet: str
+    score: float