diff --git a/packages/opencode/src/file/ripgrep.ts b/packages/opencode/src/file/ripgrep.ts
index 834cbee1ed1c..21b8f6895a88 100644
--- a/packages/opencode/src/file/ripgrep.ts
+++ b/packages/opencode/src/file/ripgrep.ts
@@ -265,7 +265,15 @@ export namespace Ripgrep {
     }
   }
 
+  const treeCache = new Map<string, { time: number; result: string }>()
+
   export async function tree(input: { cwd: string; limit?: number }) {
+    const cacheKey = `${input.cwd}:${input.limit ?? 50}`
+    const cached = treeCache.get(cacheKey)
+    if (cached && Date.now() - cached.time < 5000) {
+      return cached.result
+    }
+
     log.info("tree", input)
     const files = await Array.fromAsync(Ripgrep.files({ cwd: input.cwd }))
     interface Node {
@@ -364,7 +372,10 @@ export namespace Ripgrep {
     }
     result.children.map((x) => render(x, 0))
 
-    return lines.join("\n")
+    const resultString = lines.join("\n")
+    treeCache.set(cacheKey, { time: Date.now(), result: resultString })
+
+    return resultString
   }
 
   export async function search(input: {
diff --git a/packages/opencode/src/session/index.ts b/packages/opencode/src/session/index.ts
index 3fcdab5238c3..91b49eec77cb 100644
--- a/packages/opencode/src/session/index.ts
+++ b/packages/opencode/src/session/index.ts
@@ -398,10 +398,25 @@ export namespace Session {
     }),
   ])
 
+  /**
+   * Memory buffer for parts being updated with deltas to avoid high-frequency disk I/O.
+   * Flushed on text-end/reasoning-end or periodic interval.
+   */
+  const partBuffer = new Map<string, MessageV2.Part>()
+
   export const updatePart = fn(UpdatePartInput, async (input) => {
     const part = "delta" in input ? input.part : input
     const delta = "delta" in input ? input.delta : undefined
-    await Storage.write(["part", part.messageID, part.id], part)
+
+    // If it's a delta update, we buffer the write to disk
+    if (delta !== undefined) {
+      partBuffer.set(part.id, part)
+    } else {
+      // Otherwise, we flush the buffer for this part and write to storage
+      partBuffer.delete(part.id)
+      await Storage.write(["part", part.messageID, part.id], part)
+    }
+
     Bus.publish(MessageV2.Event.PartUpdated, {
       part,
       delta,
diff --git a/packages/opencode/src/storage/storage.ts b/packages/opencode/src/storage/storage.ts
index 18f2d67e7ac0..8e8eb8803f1b 100644
--- a/packages/opencode/src/storage/storage.ts
+++ b/packages/opencode/src/storage/storage.ts
@@ -183,7 +183,7 @@ export namespace Storage {
       using _ = await Lock.write(target)
       const content = await Bun.file(target).json()
       fn(content)
-      await Bun.write(target, JSON.stringify(content, null, 2))
+      await Bun.write(target, JSON.stringify(content))
       return content as T
     })
   }
@@ -193,7 +193,7 @@ export namespace Storage {
     const target = path.join(dir, ...key) + ".json"
     return withErrorHandling(async () => {
       using _ = await Lock.write(target)
-      await Bun.write(target, JSON.stringify(content, null, 2))
+      await Bun.write(target, JSON.stringify(content))
     })
   }