diff --git a/api/tangled/repoblob.go b/api/tangled/repoblob.go
--- a/api/tangled/repoblob.go
+++ b/api/tangled/repoblob.go
@@ -21,8 +21,6 @@
 	Hash string `json:"hash" cborgen:"hash"`
 	// message: Commit message
 	Message string `json:"message" cborgen:"message"`
-	// shortHash: Short commit hash
-	ShortHash *string `json:"shortHash,omitempty" cborgen:"shortHash,omitempty"`
 	// when: Commit timestamp
 	When string `json:"when" cborgen:"when"`
 }
diff --git a/api/tangled/repotree.go b/api/tangled/repotree.go
--- a/api/tangled/repotree.go
+++ b/api/tangled/repotree.go
@@ -16,6 +16,7 @@
 
 // RepoTree_LastCommit is a "lastCommit" in the sh.tangled.repo.tree schema.
 type RepoTree_LastCommit struct {
+	Author *RepoTree_Signature `json:"author,omitempty" cborgen:"author,omitempty"`
 	// hash: Commit hash
 	Hash string `json:"hash" cborgen:"hash"`
 	// message: Commit message
@@ -27,8 +28,9 @@
 // RepoTree_Output is the output of a sh.tangled.repo.tree call.
 type RepoTree_Output struct {
 	// dotdot: Parent directory path
-	Dotdot *string               `json:"dotdot,omitempty" cborgen:"dotdot,omitempty"`
-	Files  []*RepoTree_TreeEntry `json:"files" cborgen:"files"`
+	Dotdot     *string               `json:"dotdot,omitempty" cborgen:"dotdot,omitempty"`
+	Files      []*RepoTree_TreeEntry `json:"files" cborgen:"files"`
+	LastCommit *RepoTree_LastCommit  `json:"lastCommit,omitempty" cborgen:"lastCommit,omitempty"`
 	// parent: The parent path in the tree
 	Parent *string `json:"parent,omitempty" cborgen:"parent,omitempty"`
 	// readme: Readme for this file tree
@@ -43,6 +45,16 @@
 	Contents string `json:"contents" cborgen:"contents"`
 	// filename: Name of the readme file
 	Filename string `json:"filename" cborgen:"filename"`
+}
+
+// RepoTree_Signature is a "signature" in the sh.tangled.repo.tree schema.
+type RepoTree_Signature struct {
+	// email: Author email
+	Email string `json:"email" cborgen:"email"`
+	// name: Author name
+	Name string `json:"name" cborgen:"name"`
+	// when: Author timestamp
+	When string `json:"when" cborgen:"when"`
 }
 
 // RepoTree_TreeEntry is a "treeEntry" in the sh.tangled.repo.tree schema.
diff --git a/lexicons/repo/blob.json b/lexicons/repo/blob.json
--- a/lexicons/repo/blob.json
+++ b/lexicons/repo/blob.json
@@ -115,10 +115,6 @@
           "type": "string",
           "description": "Commit hash"
         },
-        "shortHash": {
-          "type": "string",
-          "description": "Short commit hash"
-        },
         "message": {
           "type": "string",
           "description": "Commit message"
diff --git a/lexicons/repo/tree.json b/lexicons/repo/tree.json
--- a/lexicons/repo/tree.json
+++ b/lexicons/repo/tree.json
@@ -6,7 +6,10 @@
       "type": "query",
       "parameters": {
         "type": "params",
-        "required": ["repo", "ref"],
+        "required": [
+          "repo",
+          "ref"
+        ],
         "properties": {
           "repo": {
             "type": "string",
@@ -27,7 +30,10 @@
         "encoding": "application/json",
         "schema": {
           "type": "object",
-          "required": ["ref", "files"],
+          "required": [
+            "ref",
+            "files"
+          ],
           "properties": {
             "ref": {
               "type": "string",
@@ -45,6 +51,10 @@
               "type": "ref",
               "ref": "#readme",
               "description": "Readme for this file tree"
+            },
+            "lastCommit": {
+              "type": "ref",
+              "ref": "#lastCommit"
             },
             "files": {
               "type": "array",
@@ -77,7 +87,10 @@
     },
     "readme": {
       "type": "object",
-      "required": ["filename", "contents"],
+      "required": [
+        "filename",
+        "contents"
+      ],
       "properties": {
         "filename": {
           "type": "string",
@@ -91,7 +104,11 @@
     },
     "treeEntry": {
       "type": "object",
-      "required": ["name", "mode", "size"],
+      "required": [
+        "name",
+        "mode",
+        "size"
+      ],
       "properties": {
         "name": {
           "type": "string",
@@ -113,7 +130,11 @@
     },
     "lastCommit": {
       "type": "object",
-      "required": ["hash", "message", "when"],
+      "required": [
+        "hash",
+        "message",
+        "when"
+      ],
       "properties": {
         "hash": {
           "type": "string",
@@ -123,10 +144,37 @@
           "type": "string",
           "description": "Commit message"
         },
+        "author": {
+          "type": "ref",
+          "ref": "#signature"
+        },
         "when": {
           "type": "string",
           "format": "datetime",
           "description": "Commit timestamp"
+        }
+      }
+    },
+    "signature": {
+      "type": "object",
+      "required": [
+        "name",
+        "email",
+        "when"
+      ],
+      "properties": {
+        "name": {
+          "type": "string",
+          "description": "Author name"
+        },
+        "email": {
+          "type": "string",
+          "description": "Author email"
+        },
+        "when": {
+          "type": "string",
+          "format": "datetime",
+          "description": "Author timestamp"
         }
       }
     }