Navigate to snapshots from the transcript

api/openapi.yaml

@@ -254,9 +254,12 @@ paths:
       description: >
         Everything in the task's worktree (committed, staged, unstaged and untracked, respecting .gitignore) as a tree,
         compared with the merge-base of the task branch and the project's default branch, or with since when given.
-        The worktree's own index is not touched.
+        The worktree's own index is not touched. With snapshot, the tree is that snapshot's instead, compared with the
+        merge-base of its commit and the default branch, or with the previous snapshot's tree when step is true.
       parameters:
-        - { name: since, in: query, required: false, schema: { type: string }, description: "A commit to compare with instead of the merge-base, such as a user.message event's head." }
+        - { name: since, in: query, required: false, schema: { type: string }, description: "A commit to compare with instead of the merge-base, such as a user.message event's head. Not allowed with snapshot." }
+        - { name: snapshot, in: query, required: false, schema: { type: integer }, description: "A snapshot's n: show the task as it was in that snapshot rather than the live worktree." }
+        - { name: step, in: query, required: false, schema: { type: boolean }, description: "With snapshot: compare with the previous snapshot (the snapshot commit's parent for the first one)." }
       responses:
         "200":
           description: Per-file stats.
@@ -641,8 +644,8 @@ components:
       type: object
       required: [base, tree, files]
       properties:
-        base: { type: string, description: Merge-base commit of the task branch and the default branch. }
-        tree: { type: string, description: Tree of the worktree as if everything were staged. }
+        base: { type: string, description: "The commit or tree compared with: the merge-base of the task branch and the default branch, since, or the previous snapshot's tree." }
+        tree: { type: string, description: "Tree of the worktree as if everything were staged, or the snapshot's tree." }
         files:
           type: array
           items: { $ref: "#/components/schemas/FileChange" }