diff --git a/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx b/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
index d049ec4373c..a9e4b232966 100644
--- a/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
+++ b/packages/opencode/src/cli/cmd/tui/routes/session/index.tsx
@@ -911,6 +911,7 @@ export function Session() {
               viewportOptions={{
                 paddingRight: showScrollbar() ? 1 : 0,
               }}
+              viewportCulling={true}
               verticalScrollbarOptions={{
                 paddingLeft: 1,
                 visible: showScrollbar(),
diff --git a/packages/opencode/src/snapshot/index.ts b/packages/opencode/src/snapshot/index.ts
index 0bbb1115e61..f0ba009b27c 100644
--- a/packages/opencode/src/snapshot/index.ts
+++ b/packages/opencode/src/snapshot/index.ts
@@ -15,26 +15,29 @@ export namespace Snapshot {
     const cfg = await Config.get()
     if (cfg.snapshot === false) return
     const git = gitdir()
+    const worktree = await worktreeRoot()
+    const env = { ...process.env, GIT_INDEX_FILE: indexFile(git, worktree) }
     if (await fs.mkdir(git, { recursive: true })) {
       await $`git init`
         .env({
-          ...process.env,
+          ...env,
           GIT_DIR: git,
-          GIT_WORK_TREE: Instance.worktree,
+          GIT_WORK_TREE: worktree,
         })
         .quiet()
         .nothrow()
       // Configure git to not convert line endings on Windows
-      await $`git --git-dir ${git} config core.autocrlf false`.quiet().nothrow()
+      await $`git --git-dir ${git} config core.autocrlf false`.env(env).quiet().nothrow()
       log.info("initialized")
     }
-    await $`git --git-dir ${git} --work-tree ${Instance.worktree} add .`.quiet().cwd(Instance.directory).nothrow()
-    const hash = await $`git --git-dir ${git} --work-tree ${Instance.worktree} write-tree`
+    await $`git --git-dir ${git} --work-tree ${worktree} add .`.env(env).quiet().cwd(Instance.directory).nothrow()
+    const hash = await $`git --git-dir ${git} --work-tree ${worktree} write-tree`
+      .env(env)
       .quiet()
       .cwd(Instance.directory)
       .nothrow()
       .text()
-    log.info("tracking", { hash, cwd: Instance.directory, git })
+    log.info("tracking", { hash, cwd: Instance.directory, git, worktree })
     return hash.trim()
   }
 
@@ -46,9 +49,12 @@ export namespace Snapshot {
 
   export async function patch(hash: string): Promise<Patch> {
     const git = gitdir()
-    await $`git --git-dir ${git} --work-tree ${Instance.worktree} add .`.quiet().cwd(Instance.directory).nothrow()
+    const worktree = await worktreeRoot()
+    const env = { ...process.env, GIT_INDEX_FILE: indexFile(git, worktree) }
+    await $`git --git-dir ${git} --work-tree ${worktree} add .`.env(env).quiet().cwd(Instance.directory).nothrow()
     const result =
-      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --no-ext-diff --name-only ${hash} -- .`
+      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${worktree} diff --no-ext-diff --name-only ${hash} -- .`
+        .env(env)
         .quiet()
         .cwd(Instance.directory)
         .nothrow()
@@ -67,17 +73,20 @@ export namespace Snapshot {
         .split("\n")
         .map((x) => x.trim())
         .filter(Boolean)
-        .map((x) => path.join(Instance.worktree, x)),
+        .map((x) => path.join(worktree, x)),
     }
   }
 
   export async function restore(snapshot: string) {
     log.info("restore", { commit: snapshot })
     const git = gitdir()
+    const worktree = await worktreeRoot()
+    const env = { ...process.env, GIT_INDEX_FILE: indexFile(git, worktree) }
     const result =
-      await $`git --git-dir ${git} --work-tree ${Instance.worktree} read-tree ${snapshot} && git --git-dir ${git} --work-tree ${Instance.worktree} checkout-index -a -f`
+      await $`git --git-dir ${git} --work-tree ${worktree} read-tree ${snapshot} && git --git-dir ${git} --work-tree ${worktree} checkout-index -a -f`
+        .env(env)
         .quiet()
-        .cwd(Instance.worktree)
+        .cwd(worktree)
         .nothrow()
 
     if (result.exitCode !== 0) {
@@ -93,20 +102,25 @@ export namespace Snapshot {
   export async function revert(patches: Patch[]) {
     const files = new Set<string>()
     const git = gitdir()
+    const worktree = await worktreeRoot()
+    const env = { ...process.env, GIT_INDEX_FILE: indexFile(git, worktree) }
     for (const item of patches) {
       for (const file of item.files) {
         if (files.has(file)) continue
         log.info("reverting", { file, hash: item.hash })
-        const result = await $`git --git-dir ${git} --work-tree ${Instance.worktree} checkout ${item.hash} -- ${file}`
+        const relativePath = path.relative(worktree, file)
+        const pathspec = relativePath.startsWith("..") ? file : relativePath
+        const result = await $`git --git-dir ${git} --work-tree ${worktree} checkout ${item.hash} -- ${pathspec}`
+          .env(env)
           .quiet()
-          .cwd(Instance.worktree)
+          .cwd(worktree)
           .nothrow()
         if (result.exitCode !== 0) {
-          const relativePath = path.relative(Instance.worktree, file)
           const checkTree =
-            await $`git --git-dir ${git} --work-tree ${Instance.worktree} ls-tree ${item.hash} -- ${relativePath}`
+            await $`git --git-dir ${git} --work-tree ${worktree} ls-tree ${item.hash} -- ${relativePath}`
+              .env(env)
               .quiet()
-              .cwd(Instance.worktree)
+              .cwd(worktree)
               .nothrow()
           if (checkTree.exitCode === 0 && checkTree.text().trim()) {
             log.info("file existed in snapshot but checkout failed, keeping", {
@@ -124,11 +138,14 @@ export namespace Snapshot {
 
   export async function diff(hash: string) {
     const git = gitdir()
-    await $`git --git-dir ${git} --work-tree ${Instance.worktree} add .`.quiet().cwd(Instance.directory).nothrow()
+    const worktree = await worktreeRoot()
+    const env = { ...process.env, GIT_INDEX_FILE: indexFile(git, worktree) }
+    await $`git --git-dir ${git} --work-tree ${worktree} add .`.env(env).quiet().cwd(Instance.directory).nothrow()
     const result =
-      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --no-ext-diff ${hash} -- .`
+      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${worktree} diff --no-ext-diff ${hash} -- .`
+        .env(env)
         .quiet()
-        .cwd(Instance.worktree)
+        .cwd(Instance.directory)
         .nothrow()
 
     if (result.exitCode !== 0) {
@@ -158,8 +175,11 @@ export namespace Snapshot {
   export type FileDiff = z.infer<typeof FileDiff>
   export async function diffFull(from: string, to: string): Promise<FileDiff[]> {
     const git = gitdir()
+    const worktree = await worktreeRoot()
+    const env = { ...process.env, GIT_INDEX_FILE: indexFile(git, worktree) }
     const result: FileDiff[] = []
-    for await (const line of $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --no-ext-diff --no-renames --numstat ${from} ${to} -- .`
+    for await (const line of $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${worktree} diff --no-ext-diff --no-renames --numstat ${from} ${to} -- .`
+      .env(env)
       .quiet()
       .cwd(Instance.directory)
       .nothrow()
@@ -169,13 +189,15 @@ export namespace Snapshot {
       const isBinaryFile = additions === "-" && deletions === "-"
       const before = isBinaryFile
         ? ""
-        : await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} show ${from}:${file}`
+        : await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${worktree} show ${from}:${file}`
+            .env(env)
             .quiet()
             .nothrow()
             .text()
       const after = isBinaryFile
         ? ""
-        : await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} show ${to}:${file}`
+        : await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${worktree} show ${to}:${file}`
+            .env(env)
             .quiet()
             .nothrow()
             .text()
@@ -194,4 +216,17 @@ export namespace Snapshot {
     const project = Instance.project
     return path.join(Global.Path.data, "snapshot", project.id)
   }
+
+  function indexFile(git: string, worktree: string) {
+    const key = Bun.hash.xxHash64(worktree).toString(16)
+    return path.join(git, `index-${key}`)
+  }
+
+  async function worktreeRoot() {
+    const result = await $`git rev-parse --show-toplevel`.quiet().nothrow().cwd(Instance.directory)
+    if (result.exitCode !== 0) return Instance.worktree
+    const resolved = result.text().trim()
+    if (!resolved) return Instance.worktree
+    return path.resolve(Instance.directory, resolved)
+  }
 }