diff --git a/hydra-node/json-schemas/api.yaml b/hydra-node/json-schemas/api.yaml
index 0137a73f0c4..487704853c1 100644
--- a/hydra-node/json-schemas/api.yaml
+++ b/hydra-node/json-schemas/api.yaml
@@ -1555,7 +1555,7 @@ components:
             tag:
               type: string
               enum: ["InvalidHeadId"]
-            headSeed:
+            headId:
               $ref: "api.yaml#/components/schemas/HeadId"
         - title: FailedToConstructAbortTx
           description: |
diff --git a/hydra-node/json-schemas/logs.yaml b/hydra-node/json-schemas/logs.yaml
index 2acad0f8a44..9145f3e91df 100644
--- a/hydra-node/json-schemas/logs.yaml
+++ b/hydra-node/json-schemas/logs.yaml
@@ -1732,10 +1732,10 @@ definitions:
         additionalProperties: false
         required:
           - tag
-          - contestationPeriod
-          - parties
           - headId
           - headSeed
+          - headParameters
+          - participants
         description: >-
           The initial transaction of the Head, announcing various parameters and
           the parties, has been posted on-chain.
@@ -1743,19 +1743,16 @@ definitions:
           tag:
             type: string
             enum: ["OnInitTx"]
-          contestationPeriod:
-            type: number
-            description: >-
-              The length of the contestaion period, in seconds, represented as a
-              decimal number.
-          parties:
-            type: array
-            items:
-              $ref: "api.yaml#/components/schemas/Party"
           headId:
             $ref: "api.yaml#/components/schemas/HeadId"
           headSeed:
             $ref: "api.yaml#/components/schemas/HeadSeed"
+          headParameters:
+            $ref: "api.yaml#/components/schemas/HeadParameters"
+          participants:
+            type: array
+            items:
+              $ref: "api.yaml#/components/schemas/OnChainId"
       - title: OnCommitTx
         type: object
         additionalProperties: false
@@ -1806,12 +1803,15 @@ definitions:
         additionalProperties: false
         required:
           - tag
+          - headId
           - snapshotNumber
           - contestationDeadline
         properties:
           tag:
             type: string
             enum: ["OnCloseTx"]
+          headId:
+            $ref: "api.yaml#/components/schemas/HeadId"
           snapshotNumber:
             type: integer
             minimum: 0
@@ -1822,11 +1822,14 @@ definitions:
         additionalProperties: false
         required:
           - tag
+          - headId
           - snapshotNumber
         properties:
           tag:
             type: string
             enum: ["OnContestTx"]
+          headId:
+            $ref: "api.yaml#/components/schemas/HeadId"
           snapshotNumber:
             type: integer
             minimum: 0
@@ -1835,10 +1838,13 @@ definitions:
         additionalProperties: false
         required:
           - tag
+          - headId
         properties:
           tag:
             type: string
             enum: ["OnFanoutTx"]
+          headId:
+            $ref: "api.yaml#/components/schemas/HeadId"
 
   Effect:
     description: >-
diff --git a/hydra-node/src/Hydra/Chain.hs b/hydra-node/src/Hydra/Chain.hs
index 8e9a9d7ecdc..c6585a9af77 100644
--- a/hydra-node/src/Hydra/Chain.hs
+++ b/hydra-node/src/Hydra/Chain.hs
@@ -95,7 +95,11 @@ data OnChainTx tx
       , headParameters :: HeadParameters
       , participants :: [OnChainId]
       }
-  | OnCommitTx {headId :: HeadId, party :: Party, committed :: UTxOType tx}
+  | OnCommitTx
+      { headId :: HeadId
+      , party :: Party
+      , committed :: UTxOType tx
+      }
   | OnAbortTx {headId :: HeadId}
   | OnCollectComTx {headId :: HeadId}
   | OnCloseTx
@@ -103,7 +107,10 @@ data OnChainTx tx
       , snapshotNumber :: SnapshotNumber
       , contestationDeadline :: UTCTime
       }
-  | OnContestTx {headId :: HeadId, snapshotNumber :: SnapshotNumber}
+  | OnContestTx
+      { headId :: HeadId
+      , snapshotNumber :: SnapshotNumber
+      }
   | OnFanoutTx {headId :: HeadId}
   deriving stock (Generic)