diff --git a/src/schema.py b/src/schema.py
index d9637a2..7f5f545 100644
--- a/src/schema.py
+++ b/src/schema.py
@@ -1,6 +1,7 @@
 from src import formatting
 from time import time
 
+
 def base():
     return {
         "error": False
@@ -19,49 +20,54 @@ def error(code, description):
     result = base()
     result.update({
         "error": {
-            "description": description,
-            "code": code
+            "description": description, # string
+            "code": code                # integer
         }
     })
     return result
 
 
 def user_internal(ID, auth_hash, name, quip, bio, admin):
+    if not quip: quip = ""
+    if not bio: bio =   ""
     return {
-        "user_id":   ID,
-        "quip":      quip,
-        "name":      name,
-        "bio":       bio,
-        "admin":     admin,
-        "auth_hash": auth_hash
+        "user_id":   ID,       # string
+        "quip":      quip,     # (possibly empty) string
+        "bio":       bio,      # (possibly empty) string
+        "name":      name,     # string
+        "admin":     admin,    # boolean
+        "auth_hash": auth_hash # SHA256 string
     }
 
 
 def user_external(ID, name, quip, bio, admin):
+    if not quip: quip = ""
+    if not bio: bio =   ""
     return {
-        "user_id":   ID,
-        "quip":      quip,
-        "name":      name,
-        "bio":       bio,
-        "admin":     admin
+        "user_id":   ID,   # string
+        "quip":      quip, # (possibly empty) string
+        "name":      name, # string
+        "bio":       bio,  # string
+        "admin":     admin # boolean
     }
 
 
 def thread(ID, author, body, title, tags):
+    if not tags: tags = list()
     body = formatting.parse(body, doquotes=False)
     now = time()
     return {
-        "thread_id":   ID,
-        "post_id":     1,
-        "author":      author,
-        "body":        body,
-        "title":       title,
-        "tags":        tags,
-        "replies":     list(),
-        "reply_count": 0,
-        "lastmod":     now,
-        "edited":      False,
-        "created":     now
+        "thread_id":   ID,     # string
+        "post_id":     1,      # integer
+        "author":      author, # string
+        "body":        body,   # string
+        "title":       title,  # string
+        "tags":        tags,   # (possibly empty) list of strings
+        "replies":     list(), # (possibly empty) list of reply objects
+        "reply_count": 0,      # integer
+        "edited":      False,  # boolean
+        "lastmod":     now,    # floating point unix timestamp
+        "created":     now     # floating point unix timestamp
     }
 
 
@@ -69,10 +75,10 @@ def reply(ID, author, body):
     body = formatting.parse(body)
     now = time()
     return {
-        "post_id":  ID,
-        "author":   author,
-        "body":     body,
-        "lastmod":  now,
-        "edited":   False,
-        "created":  now
+        "post_id":  ID,     # integer
+        "author":   author, # string
+        "body":     body,   # string
+        "edited":   False,  # boolean
+        "lastmod":  now,    # floating point unix timestamp
+        "created":  now     # floating point unix timestamp
     }