3 files changed, 25 insertions, 1 deletions
diff --git a/packages/opencode/src/cli/cmd/debug/snapshot.ts b/packages/opencode/src/cli/cmd/debug/snapshot.ts
index 72bbd61d7..edd5fbe2a 100644
--- a/packages/opencode/src/cli/cmd/debug/snapshot.ts
+++ b/packages/opencode/src/cli/cmd/debug/snapshot.ts
@@ -4,7 +4,7 @@ import { cmd } from "../cmd"
 
 export const SnapshotCommand = cmd({
   command: "snapshot",
-  builder: (yargs) => yargs.command(TrackCommand).command(PatchCommand).demandCommand(),
+  builder: (yargs) => yargs.command(TrackCommand).command(PatchCommand).command(DiffCommand).demandCommand(),
   async handler() {},
 })
 
@@ -31,3 +31,18 @@ const PatchCommand = cmd({
     })
   },
 })
+
+const DiffCommand = cmd({
+  command: "diff <hash>",
+  builder: (yargs) =>
+    yargs.positional("hash", {
+      type: "string",
+      description: "hash",
+      demandOption: true,
+    }),
+  async handler(args) {
+    await bootstrap({ cwd: process.cwd() }, async () => {
+      console.log(await Snapshot.diff(args.hash))
+    })
+  },
+})
diff --git a/packages/opencode/src/session/index.ts b/packages/opencode/src/session/index.ts
index 799097e85..e85073424 100644
--- a/packages/opencode/src/session/index.ts
+++ b/packages/opencode/src/session/index.ts
@@ -67,6 +67,7 @@ export namespace Session {
           messageID: z.string(),
           partID: z.string().optional(),
           snapshot: z.string().optional(),
+          diff: z.string().optional(),
         })
         .optional(),
     })
@@ -1160,6 +1161,7 @@ export namespace Session {
       const session = await get(input.sessionID)
       revert.snapshot = session.revert?.snapshot ?? (await Snapshot.track())
       await Snapshot.revert(patches)
+      if (revert.snapshot) revert.diff = await Snapshot.diff(revert.snapshot)
       return update(input.sessionID, (draft) => {
         draft.revert = revert
       })
diff --git a/packages/opencode/src/snapshot/index.ts b/packages/opencode/src/snapshot/index.ts
index a2203ecbc..d249830b0 100644
--- a/packages/opencode/src/snapshot/index.ts
+++ b/packages/opencode/src/snapshot/index.ts
@@ -94,6 +94,13 @@ export namespace Snapshot {
     }
   }
 
+  export async function diff(hash: string) {
+    const app = App.info()
+    const git = gitdir()
+    const result = await $`git --git-dir=${git} diff ${hash} -- .`.quiet().cwd(app.path.root).text()
+    return result.trim()
+  }
+
   function gitdir() {
     const app = App.info()
     return path.join(app.path.data, "snapshots")