diff --git a/event-schemas/schema/v1/m.call.answer b/event-schemas/schema/v1/m.call.answer
index 8976aa334..7baaaf7fc 100644
--- a/event-schemas/schema/v1/m.call.answer
+++ b/event-schemas/schema/v1/m.call.answer
@@ -9,23 +9,28 @@
             "type": "object",
             "properties": {
                 "call_id": {
-                    "type": "string"
+                    "type": "string",
+                    "description": "The ID of the call this event relates to."
                 },
                 "answer": {
                     "type": "object",
+                    "description": "",
                     "properties": {
                         "type": {
                             "type": "string",
-                            "enum": ["answer"]
+                            "enum": ["answer"],
+                            "description": "The type of session description. Must be 'answer'."
                         },
                         "sdp": {
-                            "type": "string"
+                            "type": "string",
+                            "description": "The SDP text of the session description."
                         }
                     },
                     "required": ["type", "sdp"]
                 },
                 "version": {
-                    "type": "number"
+                    "type": "number",
+                    "description": ""
                 }
             },
             "required": ["call_id", "answer", "version"]
diff --git a/event-schemas/schema/v1/m.call.candidates b/event-schemas/schema/v1/m.call.candidates
index 0a2937a15..93c024ee2 100644
--- a/event-schemas/schema/v1/m.call.candidates
+++ b/event-schemas/schema/v1/m.call.candidates
@@ -9,28 +9,34 @@
             "type": "object",
             "properties": {
                 "call_id": {
-                    "type": "string"
+                    "type": "string",
+                    "description": "The ID of the call this event relates to."
                 },
                 "candidates": {
                     "type": "array",
+                    "description": "Array of objects describing the candidates.",
                     "items": {
                         "type": "object",
                         "properties": {
                             "sdpMid": {
-                                "type": "string"
+                                "type": "string",
+                                "description": "The SDP media type this candidate is intended for."
                             },
                             "sdpMLineIndex": {
-                                "type": "number"
+                                "type": "number",
+                                "description": "The index of the SDP 'm' line this candidate is intended for."
                             },
                             "candidate": {
-                                "type": "string"
+                                "type": "string",
+                                "description": "The SDP 'a' line of the candidate."
                             }
                         },
                         "required": ["candidate", "sdpMLineIndex", "sdpMid"]
                     }
                 },
                 "version": {
-                    "type": "number"
+                    "type": "integer",
+                    "description": "The version of the VoIP specification this messages adheres to. This specification is version 0."
                 }
             },
             "required": ["call_id", "candidates", "version"]
diff --git a/event-schemas/schema/v1/m.call.hangup b/event-schemas/schema/v1/m.call.hangup
index 48d008b98..3704ec753 100644
--- a/event-schemas/schema/v1/m.call.hangup
+++ b/event-schemas/schema/v1/m.call.hangup
@@ -1,6 +1,7 @@
 {
     "$schema": "http://json-schema.org/draft-04/schema#",
     "type": "object",
+    "description": "Sent by either party to signal their termination of the call. This can be sent either once the call has has been established or before to abort the call.",
     "allOf": [{
         "$ref": "core#/definitions/room_event"
     }],
@@ -9,10 +10,12 @@
             "type": "object",
             "properties": {
                 "call_id": {
-                    "type": "string"
+                    "type": "string",
+                    "description": "The ID of the call this event relates to."
                 },
                 "version": {
-                    "type": "number"
+                    "type": "integer",
+                    "description": "The version of the VoIP specification this message adheres to. This specification is version 0."
                 }
             },
             "required": ["call_id", "version"]
diff --git a/event-schemas/schema/v1/m.call.invite b/event-schemas/schema/v1/m.call.invite
index 4bdbccab6..a2aa98a30 100644
--- a/event-schemas/schema/v1/m.call.invite
+++ b/event-schemas/schema/v1/m.call.invite
@@ -9,26 +9,35 @@
             "type": "object",
             "properties": {
                 "call_id": {
-                    "type": "string"
+                    "type": "string",
+                    "description": "A unique identifer for the call."
                 },
                 "offer": {
                     "type": "object",
+                    "description": "The session description object",
                     "properties": {
                         "type": {
                             "type": "string",
-                            "enum": ["offer"]
+                            "enum": ["offer"],
+                            "description": "The type of session description. Must be 'offer'."
                         },
                         "sdp": {
-                            "type": "string"
+                            "type": "string",
+                            "description": "The SDP text of the session description."
                         }
                     },
                     "required": ["type", "sdp"]
                 },
                 "version": {
-                    "type": "number"
+                    "type": "integer",
+                    "description": "The version of the VoIP specification this message adheres to. This specification is version 0."
+                },
+                "lifetime": {
+                    "type": "integer",
+                    "description": "The time in milliseconds that the invite is valid for. Once the invite age exceeds this value, clients should discard it. They should also no longer show the call as awaiting an answer in the UI."
                 }
             },
-            "required": ["call_id", "offer", "version"]
+            "required": ["call_id", "offer", "version", "lifetime"]
         },
         "type": {
             "type": "string",