Revert: all refactor commits migrating from Bun.file() to Filesystem module

24 files changed, 174 insertions, 294 deletions

diff --git a/packages/opencode/src/cli/cmd/tui/thread.ts b/packages/opencode/src/cli/cmd/tui/thread.ts
index 50f63c3df..9eb296032 100644
--- a/packages/opencode/src/cli/cmd/tui/thread.ts
+++ b/packages/opencode/src/cli/cmd/tui/thread.ts
@@ -3,12 +3,10 @@ import { tui } from "./app"
 import { Rpc } from "@/util/rpc"
 import { type rpc } from "./worker"
 import path from "path"
-import { fileURLToPath } from "url"
 import { UI } from "@/cli/ui"
 import { iife } from "@/util/iife"
 import { Log } from "@/util/log"
 import { withNetworkOptions, resolveNetworkOptions } from "@/cli/network"
-import { Filesystem } from "@/util/filesystem"
 import type { Event } from "@opencode-ai/sdk/v2"
 import type { EventSource } from "./context/sdk"
 import { win32DisableProcessedInput, win32InstallCtrlCGuard } from "./win32"
@@ -101,7 +99,7 @@ export const TuiThreadCommand = cmd({
       const distWorker = new URL("./cli/cmd/tui/worker.js", import.meta.url)
       const workerPath = await iife(async () => {
         if (typeof OPENCODE_WORKER_PATH !== "undefined") return OPENCODE_WORKER_PATH
-        if (await Filesystem.exists(fileURLToPath(distWorker))) return distWorker
+        if (await Bun.file(distWorker).exists()) return distWorker
         return localWorker
       })
       try {
diff --git a/packages/opencode/src/lsp/client.ts b/packages/opencode/src/lsp/client.ts
index 084ccf831..8704b65ac 100644
--- a/packages/opencode/src/lsp/client.ts
+++ b/packages/opencode/src/lsp/client.ts
@@ -147,7 +147,8 @@ export namespace LSPClient {
       notify: {
         async open(input: { path: string }) {
           input.path = path.isAbsolute(input.path) ? input.path : path.resolve(Instance.directory, input.path)
-          const text = await Filesystem.readText(input.path)
+          const file = Bun.file(input.path)
+          const text = await file.text()
           const extension = path.extname(input.path)
           const languageId = LANGUAGE_EXTENSIONS[extension] ?? "plaintext"
 
diff --git a/packages/opencode/src/lsp/server.ts b/packages/opencode/src/lsp/server.ts
index a4ebeb5a2..0200be226 100644
--- a/packages/opencode/src/lsp/server.ts
+++ b/packages/opencode/src/lsp/server.ts
@@ -131,7 +131,7 @@ export namespace LSPServer {
           "bin",
           "vue-language-server.js",
         )
-        if (!(await Filesystem.exists(js))) {
+        if (!(await Bun.file(js).exists())) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "@vue/language-server"], {
             cwd: Global.Path.bin,
@@ -173,14 +173,14 @@ export namespace LSPServer {
       if (!eslint) return
       log.info("spawning eslint server")
       const serverPath = path.join(Global.Path.bin, "vscode-eslint", "server", "out", "eslintServer.js")
-      if (!(await Filesystem.exists(serverPath))) {
+      if (!(await Bun.file(serverPath).exists())) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
         log.info("downloading and building VS Code ESLint server")
         const response = await fetch("https://github.com/microsoft/vscode-eslint/archive/refs/heads/main.zip")
         if (!response.ok) return
 
         const zipPath = path.join(Global.Path.bin, "vscode-eslint.zip")
-        if (response.body) await Filesystem.writeStream(zipPath, response.body)
+        await Bun.file(zipPath).write(response)
 
         const ok = await Archive.extractZip(zipPath, Global.Path.bin)
           .then(() => true)
@@ -242,7 +242,7 @@ export namespace LSPServer {
 
       const resolveBin = async (target: string) => {
         const localBin = path.join(root, target)
-        if (await Filesystem.exists(localBin)) return localBin
+        if (await Bun.file(localBin).exists()) return localBin
 
         const candidates = Filesystem.up({
           targets: [target],
@@ -326,7 +326,7 @@ export namespace LSPServer {
     async spawn(root) {
       const localBin = path.join(root, "node_modules", ".bin", "biome")
       let bin: string | undefined
-      if (await Filesystem.exists(localBin)) bin = localBin
+      if (await Bun.file(localBin).exists()) bin = localBin
       if (!bin) {
         const found = Bun.which("biome")
         if (found) bin = found
@@ -467,7 +467,7 @@ export namespace LSPServer {
         const potentialPythonPath = isWindows
           ? path.join(venvPath, "Scripts", "python.exe")
           : path.join(venvPath, "bin", "python")
-        if (await Filesystem.exists(potentialPythonPath)) {
+        if (await Bun.file(potentialPythonPath).exists()) {
           initialization["pythonPath"] = potentialPythonPath
           break
         }
@@ -479,7 +479,7 @@ export namespace LSPServer {
           const potentialTyPath = isWindows
             ? path.join(venvPath, "Scripts", "ty.exe")
             : path.join(venvPath, "bin", "ty")
-          if (await Filesystem.exists(potentialTyPath)) {
+          if (await Bun.file(potentialTyPath).exists()) {
             binary = potentialTyPath
             break
           }
@@ -511,7 +511,7 @@ export namespace LSPServer {
       const args = []
       if (!binary) {
         const js = path.join(Global.Path.bin, "node_modules", "pyright", "dist", "pyright-langserver.js")
-        if (!(await Filesystem.exists(js))) {
+        if (!(await Bun.file(js).exists())) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "pyright"], {
             cwd: Global.Path.bin,
@@ -536,7 +536,7 @@ export namespace LSPServer {
         const potentialPythonPath = isWindows
           ? path.join(venvPath, "Scripts", "python.exe")
           : path.join(venvPath, "bin", "python")
-        if (await Filesystem.exists(potentialPythonPath)) {
+        if (await Bun.file(potentialPythonPath).exists()) {
           initialization["pythonPath"] = potentialPythonPath
           break
         }
@@ -571,7 +571,7 @@ export namespace LSPServer {
           process.platform === "win32" ? "language_server.bat" : "language_server.sh",
         )
 
-        if (!(await Filesystem.exists(binary))) {
+        if (!(await Bun.file(binary).exists())) {
           const elixir = Bun.which("elixir")
           if (!elixir) {
             log.error("elixir is required to run elixir-ls")
@@ -584,7 +584,7 @@ export namespace LSPServer {
           const response = await fetch("https://github.com/elixir-lsp/elixir-ls/archive/refs/heads/master.zip")
           if (!response.ok) return
           const zipPath = path.join(Global.Path.bin, "elixir-ls.zip")
-          if (response.body) await Filesystem.writeStream(zipPath, response.body)
+          await Bun.file(zipPath).write(response)
 
           const ok = await Archive.extractZip(zipPath, Global.Path.bin)
             .then(() => true)
@@ -692,7 +692,7 @@ export namespace LSPServer {
         }
 
         const tempPath = path.join(Global.Path.bin, assetName)
-        if (downloadResponse.body) await Filesystem.writeStream(tempPath, downloadResponse.body)
+        await Bun.file(tempPath).write(downloadResponse)
 
         if (ext === "zip") {
           const ok = await Archive.extractZip(tempPath, Global.Path.bin)
@@ -710,7 +710,7 @@ export namespace LSPServer {
 
         bin = path.join(Global.Path.bin, "zls" + (platform === "win32" ? ".exe" : ""))
 
-        if (!(await Filesystem.exists(bin))) {
+        if (!(await Bun.file(bin).exists())) {
           log.error("Failed to extract zls binary")
           return
         }
@@ -857,7 +857,7 @@ export namespace LSPServer {
         // Stop at filesystem root
         const cargoTomlPath = path.join(currentDir, "Cargo.toml")
         try {
-          const cargoTomlContent = await Filesystem.readText(cargoTomlPath)
+          const cargoTomlContent = await Bun.file(cargoTomlPath).text()
           if (cargoTomlContent.includes("[workspace]")) {
             return currentDir
           }
@@ -907,7 +907,7 @@ export namespace LSPServer {
 
       const ext = process.platform === "win32" ? ".exe" : ""
       const direct = path.join(Global.Path.bin, "clangd" + ext)
-      if (await Filesystem.exists(direct)) {
+      if (await Bun.file(direct).exists()) {
         return {
           process: spawn(direct, args, {
             cwd: root,
@@ -920,7 +920,7 @@ export namespace LSPServer {
         if (!entry.isDirectory()) continue
         if (!entry.name.startsWith("clangd_")) continue
         const candidate = path.join(Global.Path.bin, entry.name, "bin", "clangd" + ext)
-        if (await Filesystem.exists(candidate)) {
+        if (await Bun.file(candidate).exists()) {
           return {
             process: spawn(candidate, args, {
               cwd: root,
@@ -990,7 +990,7 @@ export namespace LSPServer {
         log.error("Failed to write clangd archive")
         return
       }
-      await Filesystem.write(archive, Buffer.from(buf))
+      await Bun.write(archive, buf)
 
       const zip = name.endsWith(".zip")
       const tar = name.endsWith(".tar.xz")
@@ -1014,7 +1014,7 @@ export namespace LSPServer {
       await fs.rm(archive, { force: true })
 
       const bin = path.join(Global.Path.bin, "clangd_" + tag, "bin", "clangd" + ext)
-      if (!(await Filesystem.exists(bin))) {
+      if (!(await Bun.file(bin).exists())) {
         log.error("Failed to extract clangd binary")
         return
       }
@@ -1045,7 +1045,7 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         const js = path.join(Global.Path.bin, "node_modules", "svelte-language-server", "bin", "server.js")
-        if (!(await Filesystem.exists(js))) {
+        if (!(await Bun.file(js).exists())) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "svelte-language-server"], {
             cwd: Global.Path.bin,
@@ -1092,7 +1092,7 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         const js = path.join(Global.Path.bin, "node_modules", "@astrojs", "language-server", "bin", "nodeServer.js")
-        if (!(await Filesystem.exists(js))) {
+        if (!(await Bun.file(js).exists())) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "@astrojs/language-server"], {
             cwd: Global.Path.bin,
@@ -1248,7 +1248,7 @@ export namespace LSPServer {
       const distPath = path.join(Global.Path.bin, "kotlin-ls")
       const launcherScript =
         process.platform === "win32" ? path.join(distPath, "kotlin-lsp.cmd") : path.join(distPath, "kotlin-lsp.sh")
-      const installed = await Filesystem.exists(launcherScript)
+      const installed = await Bun.file(launcherScript).exists()
       if (!installed) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
         log.info("Downloading Kotlin Language Server from GitHub.")
@@ -1307,7 +1307,7 @@ export namespace LSPServer {
         }
         log.info("Installed Kotlin Language Server", { path: launcherScript })
       }
-      if (!(await Filesystem.exists(launcherScript))) {
+      if (!(await Bun.file(launcherScript).exists())) {
         log.error(`Failed to locate the Kotlin LS launcher script in the installed directory: ${distPath}.`)
         return
       }
@@ -1336,7 +1336,7 @@ export namespace LSPServer {
           "src",
           "server.js",
         )
-        const exists = await Filesystem.exists(js)
+        const exists = await Bun.file(js).exists()
         if (!exists) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "yaml-language-server"], {
@@ -1443,7 +1443,7 @@ export namespace LSPServer {
         }
 
         const tempPath = path.join(Global.Path.bin, assetName)
-        if (downloadResponse.body) await Filesystem.writeStream(tempPath, downloadResponse.body)
+        await Bun.file(tempPath).write(downloadResponse)
 
         // Unlike zls which is a single self-contained binary,
         // lua-language-server needs supporting files (meta/, locale/, etc.)
@@ -1482,7 +1482,7 @@ export namespace LSPServer {
         // Binary is located in bin/ subdirectory within the extracted archive
         bin = path.join(installDir, "bin", "lua-language-server" + (platform === "win32" ? ".exe" : ""))
 
-        if (!(await Filesystem.exists(bin))) {
+        if (!(await Bun.file(bin).exists())) {
           log.error("Failed to extract lua-language-server binary")
           return
         }
@@ -1516,7 +1516,7 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         const js = path.join(Global.Path.bin, "node_modules", "intelephense", "lib", "intelephense.js")
-        if (!(await Filesystem.exists(js))) {
+        if (!(await Bun.file(js).exists())) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "intelephense"], {
             cwd: Global.Path.bin,
@@ -1613,7 +1613,7 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         const js = path.join(Global.Path.bin, "node_modules", "bash-language-server", "out", "cli.js")
-        if (!(await Filesystem.exists(js))) {
+        if (!(await Bun.file(js).exists())) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "bash-language-server"], {
             cwd: Global.Path.bin,
@@ -1654,17 +1654,22 @@ export namespace LSPServer {
 
       if (!bin) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        log.info("downloading terraform-ls from HashiCorp releases")
+        log.info("downloading terraform-ls from GitHub releases")
 
-        const releaseResponse = await fetch("https://api.releases.hashicorp.com/v1/releases/terraform-ls/latest")
+        const releaseResponse = await fetch("https://api.github.com/repos/hashicorp/terraform-ls/releases/latest")
         if (!releaseResponse.ok) {
           log.error("Failed to fetch terraform-ls release info")
           return
         }
 
         const release = (await releaseResponse.json()) as {
-          version?: string
-          builds?: { arch?: string; os?: string; url?: string }[]
+          tag_name?: string
+          assets?: { name?: string; browser_download_url?: string }[]
+        }
+        const version = release.tag_name?.replace("v", "")
+        if (!version) {
+          log.error("terraform-ls release did not include a version tag")
+          return
         }
 
         const platform = process.platform
@@ -1673,21 +1678,23 @@ export namespace LSPServer {
         const tfArch = arch === "arm64" ? "arm64" : "amd64"
         const tfPlatform = platform === "win32" ? "windows" : platform
 
-        const builds = release.builds ?? []
-        const build = builds.find((b) => b.arch === tfArch && b.os === tfPlatform)
-        if (!build?.url) {
-          log.error(`Could not find build for ${tfPlatform}/${tfArch} terraform-ls release version ${release.version}`)
+        const assetName = `terraform-ls_${version}_${tfPlatform}_${tfArch}.zip`
+
+        const assets = release.assets ?? []
+        const asset = assets.find((a) => a.name === assetName)
+        if (!asset?.browser_download_url) {
+          log.error(`Could not find asset ${assetName} in terraform-ls release`)
           return
         }
 
-        const downloadResponse = await fetch(build.url)
+        const downloadResponse = await fetch(asset.browser_download_url)
         if (!downloadResponse.ok) {
           log.error("Failed to download terraform-ls")
           return
         }
 
-        const tempPath = path.join(Global.Path.bin, "terraform-ls.zip")
-        if (downloadResponse.body) await Filesystem.writeStream(tempPath, downloadResponse.body)
+        const tempPath = path.join(Global.Path.bin, assetName)
+        await Bun.file(tempPath).write(downloadResponse)
 
         const ok = await Archive.extractZip(tempPath, Global.Path.bin)
           .then(() => true)
@@ -1700,7 +1707,7 @@ export namespace LSPServer {
 
         bin = path.join(Global.Path.bin, "terraform-ls" + (platform === "win32" ? ".exe" : ""))
 
-        if (!(await Filesystem.exists(bin))) {
+        if (!(await Bun.file(bin).exists())) {
           log.error("Failed to extract terraform-ls binary")
           return
         }
@@ -1777,7 +1784,7 @@ export namespace LSPServer {
         }
 
         const tempPath = path.join(Global.Path.bin, assetName)
-        if (downloadResponse.body) await Filesystem.writeStream(tempPath, downloadResponse.body)
+        await Bun.file(tempPath).write(downloadResponse)
 
         if (ext === "zip") {
           const ok = await Archive.extractZip(tempPath, Global.Path.bin)
@@ -1796,7 +1803,7 @@ export namespace LSPServer {
 
         bin = path.join(Global.Path.bin, "texlab" + (platform === "win32" ? ".exe" : ""))
 
-        if (!(await Filesystem.exists(bin))) {
+        if (!(await Bun.file(bin).exists())) {
           log.error("Failed to extract texlab binary")
           return
         }
@@ -1825,7 +1832,7 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         const js = path.join(Global.Path.bin, "node_modules", "dockerfile-language-server-nodejs", "lib", "server.js")
-        if (!(await Filesystem.exists(js))) {
+        if (!(await Bun.file(js).exists())) {
           if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
           await Bun.spawn([BunProc.which(), "install", "dockerfile-language-server-nodejs"], {
             cwd: Global.Path.bin,
@@ -1983,7 +1990,7 @@ export namespace LSPServer {
         }
 
         const tempPath = path.join(Global.Path.bin, assetName)
-        if (downloadResponse.body) await Filesystem.writeStream(tempPath, downloadResponse.body)
+        await Bun.file(tempPath).write(downloadResponse)
 
         if (ext === "zip") {
           const ok = await Archive.extractZip(tempPath, Global.Path.bin)
@@ -2001,7 +2008,7 @@ export namespace LSPServer {
 
         bin = path.join(Global.Path.bin, "tinymist" + (platform === "win32" ? ".exe" : ""))
 
-        if (!(await Filesystem.exists(bin))) {
+        if (!(await Bun.file(bin).exists())) {
           log.error("Failed to extract tinymist binary")
           return
         }
diff --git a/packages/opencode/src/mcp/auth.ts b/packages/opencode/src/mcp/auth.ts
index 399986376..0f91a35b8 100644
--- a/packages/opencode/src/mcp/auth.ts
+++ b/packages/opencode/src/mcp/auth.ts
@@ -1,7 +1,6 @@
 import path from "path"
 import z from "zod"
 import { Global } from "../global"
-import { Filesystem } from "../util/filesystem"
 
 export namespace McpAuth {
   export const Tokens = z.object({
@@ -54,22 +53,25 @@ export namespace McpAuth {
   }
 
   export async function all(): Promise<Record<string, Entry>> {
-    return Filesystem.readJson<Record<string, Entry>>(filepath).catch(() => ({}))
+    const file = Bun.file(filepath)
+    return file.json().catch(() => ({}))
   }
 
   export async function set(mcpName: string, entry: Entry, serverUrl?: string): Promise<void> {
+    const file = Bun.file(filepath)
     const data = await all()
     // Always update serverUrl if provided
     if (serverUrl) {
       entry.serverUrl = serverUrl
     }
-    await Filesystem.writeJson(filepath, { ...data, [mcpName]: entry }, 0o600)
+    await Bun.write(file, JSON.stringify({ ...data, [mcpName]: entry }, null, 2), { mode: 0o600 })
   }
 
   export async function remove(mcpName: string): Promise<void> {
+    const file = Bun.file(filepath)
     const data = await all()
     delete data[mcpName]
-    await Filesystem.writeJson(filepath, data, 0o600)
+    await Bun.write(file, JSON.stringify(data, null, 2), { mode: 0o600 })
   }
 
   export async function updateTokens(mcpName: string, tokens: Tokens, serverUrl?: string): Promise<void> {
diff --git a/packages/opencode/src/project/project.ts b/packages/opencode/src/project/project.ts
index 63c1c4cad..8fa0f6c6f 100644
--- a/packages/opencode/src/project/project.ts
+++ b/packages/opencode/src/project/project.ts
@@ -86,7 +86,8 @@ export namespace Project {
         const gitBinary = Bun.which("git")
 
         // cached id calculation
-        let id = await Filesystem.readText(path.join(dotgit, "opencode"))
+        let id = await Bun.file(path.join(dotgit, "opencode"))
+          .text()
           .then((x) => x.trim())
           .catch(() => undefined)
 
@@ -124,7 +125,9 @@ export namespace Project {
 
           id = roots[0]
           if (id) {
-            void Filesystem.write(path.join(dotgit, "opencode"), id).catch(() => undefined)
+            void Bun.file(path.join(dotgit, "opencode"))
+              .write(id)
+              .catch(() => undefined)
           }
         }
 
@@ -274,9 +277,10 @@ export namespace Project {
     )
     const shortest = matches.sort((a, b) => a.length - b.length)[0]
     if (!shortest) return
-    const buffer = await Filesystem.readBytes(shortest)
-    const base64 = buffer.toString("base64")
-    const mime = Filesystem.mimeType(shortest) || "image/png"
+    const file = Bun.file(shortest)
+    const buffer = await file.arrayBuffer()
+    const base64 = Buffer.from(buffer).toString("base64")
+    const mime = file.type || "image/png"
     const url = `data:${mime};base64,${base64}`
     await update({
       projectID: input.id,
@@ -377,8 +381,10 @@ export namespace Project {
     const data = fromRow(row)
     const valid: string[] = []
     for (const dir of data.sandboxes) {
-      const s = Filesystem.stat(dir)
-      if (s?.isDirectory()) valid.push(dir)
+      const stat = await Bun.file(dir)
+        .stat()
+        .catch(() => undefined)
+      if (stat?.isDirectory()) valid.push(dir)
     }
     return valid
   }
diff --git a/packages/opencode/src/provider/models.ts b/packages/opencode/src/provider/models.ts
index bae331784..0960176e2 100644
--- a/packages/opencode/src/provider/models.ts
+++ b/packages/opencode/src/provider/models.ts
@@ -5,7 +5,6 @@ import z from "zod"
 import { Installation } from "../installation"
 import { Flag } from "../flag/flag"
 import { lazy } from "@/util/lazy"
-import { Filesystem } from "../util/filesystem"
 
 // Try to import bundled snapshot (generated at build time)
 // Falls back to undefined in dev mode when snapshot doesn't exist
@@ -86,7 +85,8 @@ export namespace ModelsDev {
   }
 
   export const Data = lazy(async () => {
-    const result = await Filesystem.readJson(Flag.OPENCODE_MODELS_PATH ?? filepath).catch(() => {})
+    const file = Bun.file(Flag.OPENCODE_MODELS_PATH ?? filepath)
+    const result = await file.json().catch(() => {})
     if (result) return result
     // @ts-ignore
     const snapshot = await import("./models-snapshot")
@@ -104,6 +104,7 @@ export namespace ModelsDev {
   }
 
   export async function refresh() {
+    const file = Bun.file(filepath)
     const result = await fetch(`${url()}/api.json`, {
       headers: {
         "User-Agent": Installation.USER_AGENT,
@@ -115,7 +116,7 @@ export namespace ModelsDev {
       })
     })
     if (result && result.ok) {
-      await Filesystem.write(filepath, await result.text())
+      await Bun.write(file, await result.text())
       ModelsDev.Data.reset()
     }
   }
diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index 6480625e9..d94d0cbb2 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -16,7 +16,6 @@ import { Flag } from "../flag/flag"
 import { iife } from "@/util/iife"
 import { Global } from "../global"
 import path from "path"
-import { Filesystem } from "../util/filesystem"
 
 // Direct imports for bundled providers
 import { createAmazonBedrock, type AmazonBedrockProviderSettings } from "@ai-sdk/amazon-bedrock"
@@ -1292,9 +1291,8 @@ export namespace Provider {
     if (cfg.model) return parseModel(cfg.model)
 
     const providers = await list()
-    const recent = (await Filesystem.readJson<{ recent?: { providerID: string; modelID: string }[] }>(
-      path.join(Global.Path.state, "model.json"),
-    )
+    const recent = (await Bun.file(path.join(Global.Path.state, "model.json"))
+      .json()
       .then((x) => (Array.isArray(x.recent) ? x.recent : []))
       .catch(() => [])) as { providerID: string; modelID: string }[]
     for (const entry of recent) {
diff --git a/packages/opencode/src/session/instruction.ts b/packages/opencode/src/session/instruction.ts
index d65ada278..6fb2a7aeb 100644
--- a/packages/opencode/src/session/instruction.ts
+++ b/packages/opencode/src/session/instruction.ts
@@ -85,7 +85,7 @@ export namespace InstructionPrompt {
     }
 
     for (const file of globalFiles()) {
-      if (await Filesystem.exists(file)) {
+      if (await Bun.file(file).exists()) {
         paths.add(path.resolve(file))
         break
       }
@@ -120,7 +120,9 @@ export namespace InstructionPrompt {
     const paths = await systemPaths()
 
     const files = Array.from(paths).map(async (p) => {
-      const content = await Filesystem.readText(p).catch(() => "")
+      const content = await Bun.file(p)
+        .text()
+        .catch(() => "")
       return content ? "Instructions from: " + p + "\n" + content : ""
     })
 
@@ -162,7 +164,7 @@ export namespace InstructionPrompt {
   export async function find(dir: string) {
     for (const file of FILES) {
       const filepath = path.resolve(path.join(dir, file))
-      if (await Filesystem.exists(filepath)) return filepath
+      if (await Bun.file(filepath).exists()) return filepath
     }
   }
 
@@ -180,7 +182,9 @@ export namespace InstructionPrompt {
 
       if (found && found !== target && !system.has(found) && !already.has(found) && !isClaimed(messageID, found)) {
         claim(messageID, found)
-        const content = await Filesystem.readText(found).catch(() => undefined)
+        const content = await Bun.file(found)
+          .text()
+          .catch(() => undefined)
         if (content) {
           results.push({ filepath: found, content: "Instructions from: " + found + "\n" + content })
         }
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index 6ca93979e..d1f407258 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -2,7 +2,6 @@ import path from "path"
 import os from "os"
 import fs from "fs/promises"
 import z from "zod"
-import { Filesystem } from "../util/filesystem"
 import { Identifier } from "../id/id"
 import { MessageV2 } from "./message-v2"
 import { Log } from "../util/log"
@@ -1083,9 +1082,11 @@ export namespace SessionPrompt {
               // have to normalize, symbol search returns absolute paths
               // Decode the pathname since URL constructor doesn't automatically decode it
               const filepath = fileURLToPath(part.url)
-              const s = Filesystem.stat(filepath)
+              const stat = await Bun.file(filepath)
+                .stat()
+                .catch(() => undefined)
 
-              if (s?.isDirectory()) {
+              if (stat?.isDirectory()) {
                 part.mime = "application/x-directory"
               }
 
@@ -1232,13 +1233,14 @@ export namespace SessionPrompt {
                 ]
               }
 
+              const file = Bun.file(filepath)
               FileTime.read(input.sessionID, filepath)
               return [
                 {
                   messageID: info.id,
                   sessionID: input.sessionID,
                   type: "text",
-                  text: `Called the Read tool with the following input: {"filePath":"${filepath}"}`,
+                  text: `Called the Read tool with the following input: {\"filePath\":\"${filepath}\"}`,
                   synthetic: true,
                 },
                 {
@@ -1246,7 +1248,7 @@ export namespace SessionPrompt {
                   messageID: info.id,
                   sessionID: input.sessionID,
                   type: "file",
-                  url: `data:${part.mime};base64,` + (await Filesystem.readBytes(filepath)).toString("base64"),
+                  url: `data:${part.mime};base64,` + Buffer.from(await file.bytes()).toString("base64"),
                   mime: part.mime,
                   filename: part.filename!,
                   source: part.source,
@@ -1352,7 +1354,7 @@ export namespace SessionPrompt {
     // Switching from plan mode to build mode
     if (input.agent.name !== "plan" && assistantMessage?.info.agent === "plan") {
       const plan = Session.plan(input.session)
-      const exists = await Filesystem.exists(plan)
+      const exists = await Bun.file(plan).exists()
       if (exists) {
         const part = await Session.updatePart({
           id: Identifier.ascending("part"),
@@ -1371,7 +1373,7 @@ export namespace SessionPrompt {
     // Entering plan mode
     if (input.agent.name === "plan" && assistantMessage?.info.agent !== "plan") {
       const plan = Session.plan(input.session)
-      const exists = await Filesystem.exists(plan)
+      const exists = await Bun.file(plan).exists()
       if (!exists) await fs.mkdir(path.dirname(plan), { recursive: true })
       const part = await Session.updatePart({
         id: Identifier.ascending("part"),
diff --git a/packages/opencode/src/shell/shell.ts b/packages/opencode/src/shell/shell.ts
index e7b7cdb3e..2e8d48bfd 100644
--- a/packages/opencode/src/shell/shell.ts
+++ b/packages/opencode/src/shell/shell.ts
@@ -1,6 +1,5 @@
 import { Flag } from "@/flag/flag"
 import { lazy } from "@/util/lazy"
-import { Filesystem } from "@/util/filesystem"
 import path from "path"
 import { spawn, type ChildProcess } from "child_process"
 
@@ -44,7 +43,7 @@ export namespace Shell {
         // git.exe is typically at: C:\Program Files\Git\cmd\git.exe
         // bash.exe is at: C:\Program Files\Git\bin\bash.exe
         const bash = path.join(git, "..", "..", "bin", "bash.exe")
-        if (Filesystem.stat(bash)?.size) return bash
+        if (Bun.file(bash).size) return bash
       }
       return process.env.COMSPEC || "cmd.exe"
     }
diff --git a/packages/opencode/src/skill/discovery.ts b/packages/opencode/src/skill/discovery.ts
index 846002cda..a4bf97d7a 100644
--- a/packages/opencode/src/skill/discovery.ts
+++ b/packages/opencode/src/skill/discovery.ts
@@ -2,7 +2,6 @@ import path from "path"
 import { mkdir } from "fs/promises"
 import { Log } from "../util/log"
 import { Global } from "../global"
-import { Filesystem } from "../util/filesystem"
 
 export namespace Discovery {
   const log = Log.create({ service: "skill-discovery" })
@@ -20,14 +19,14 @@ export namespace Discovery {
   }
 
   async function get(url: string, dest: string): Promise<boolean> {
-    if (await Filesystem.exists(dest)) return true
+    if (await Bun.file(dest).exists()) return true
     return fetch(url)
       .then(async (response) => {
         if (!response.ok) {
           log.error("failed to download", { url, status: response.status })
           return false
         }
-        if (response.body) await Filesystem.writeStream(dest, response.body)
+        await Bun.write(dest, await response.text())
         return true
       })
       .catch((err) => {
@@ -89,7 +88,7 @@ export namespace Discovery {
         )
 
         const md = path.join(root, "SKILL.md")
-        if (await Filesystem.exists(md)) result.push(root)
+        if (await Bun.file(md).exists()) result.push(root)
       }),
     )
 
diff --git a/packages/opencode/src/storage/db.ts b/packages/opencode/src/storage/db.ts
index 6d7bfd728..0974cbe7b 100644
--- a/packages/opencode/src/storage/db.ts
+++ b/packages/opencode/src/storage/db.ts
@@ -10,7 +10,7 @@ import { Log } from "../util/log"
 import { NamedError } from "@opencode-ai/util/error"
 import z from "zod"
 import path from "path"
-import { readFileSync, readdirSync, existsSync } from "fs"
+import { readFileSync, readdirSync } from "fs"
 import * as schema from "./schema"
 
 declare const OPENCODE_MIGRATIONS: { sql: string; timestamp: number }[] | undefined
@@ -54,7 +54,7 @@ export namespace Database {
     const sql = dirs
       .map((name) => {
         const file = path.join(dir, name, "migration.sql")
-        if (!existsSync(file)) return
+        if (!Bun.file(file).size) return
         return {
           sql: readFileSync(file, "utf-8"),
           timestamp: time(name),
diff --git a/packages/opencode/src/storage/json-migration.ts b/packages/opencode/src/storage/json-migration.ts
index 268442dcf..e0684ce3c 100644
--- a/packages/opencode/src/storage/json-migration.ts
+++ b/packages/opencode/src/storage/json-migration.ts
@@ -7,7 +7,6 @@ import { SessionTable, MessageTable, PartTable, TodoTable, PermissionTable } fro
 import { SessionShareTable } from "../share/share.sql"
 import path from "path"
 import { existsSync } from "fs"
-import { Filesystem } from "../util/filesystem"
 
 export namespace JsonMigration {
   const log = Log.create({ service: "json-migration" })
@@ -83,7 +82,7 @@ export namespace JsonMigration {
       const count = end - start
       const tasks = new Array(count)
       for (let i = 0; i < count; i++) {
-        tasks[i] = Filesystem.readJson(files[start + i])
+        tasks[i] = Bun.file(files[start + i]).json()
       }
       const results = await Promise.allSettled(tasks)
       const items = new Array(count)
diff --git a/packages/opencode/src/storage/storage.ts b/packages/opencode/src/storage/storage.ts
index f5459ee49..18f2d67e7 100644
--- a/packages/opencode/src/storage/storage.ts
+++ b/packages/opencode/src/storage/storage.ts
@@ -39,7 +39,7 @@ export namespace Storage {
             cwd: path.join(project, projectDir),
             absolute: true,
           })) {
-            const json = await Filesystem.readJson<any>(msgFile)
+            const json = await Bun.file(msgFile).json()
             worktree = json.path?.root
             if (worktree) break
           }
@@ -60,15 +60,18 @@ export namespace Storage {
           if (!id) continue
           projectID = id
 
-          await Filesystem.writeJson(path.join(dir, "project", projectID + ".json"), {
-            id,
-            vcs: "git",
-            worktree,
-            time: {
-              created: Date.now(),
-              initialized: Date.now(),
-            },
-          })
+          await Bun.write(
+            path.join(dir, "project", projectID + ".json"),
+            JSON.stringify({
+              id,
+              vcs: "git",
+              worktree,
+              time: {
+                created: Date.now(),
+                initialized: Date.now(),
+              },
+            }),
+          )
 
           log.info(`migrating sessions for project ${projectID}`)
           for await (const sessionFile of new Bun.Glob("storage/session/info/*.json").scan({
@@ -80,8 +83,8 @@ export namespace Storage {
               sessionFile,
               dest,
             })
-            const session = await Filesystem.readJson<any>(sessionFile)
-            await Filesystem.writeJson(dest, session)
+            const session = await Bun.file(sessionFile).json()
+            await Bun.write(dest, JSON.stringify(session))
             log.info(`migrating messages for session ${session.id}`)
             for await (const msgFile of new Bun.Glob(`storage/session/message/${session.id}/*.json`).scan({
               cwd: fullProjectDir,
@@ -92,8 +95,8 @@ export namespace Storage {
                 msgFile,
                 dest,
               })
-              const message = await Filesystem.readJson<any>(msgFile)
-              await Filesystem.writeJson(dest, message)
+              const message = await Bun.file(msgFile).json()
+              await Bun.write(dest, JSON.stringify(message))
 
               log.info(`migrating parts for message ${message.id}`)
               for await (const partFile of new Bun.Glob(`storage/session/part/${session.id}/${message.id}/*.json`).scan(
@@ -120,32 +123,35 @@ export namespace Storage {
         cwd: dir,
         absolute: true,
       })) {
-        const session = await Filesystem.readJson<any>(item)
+        const session = await Bun.file(item).json()
         if (!session.projectID) continue
         if (!session.summary?.diffs) continue
         const { diffs } = session.summary
-        await Filesystem.write(path.join(dir, "session_diff", session.id + ".json"), JSON.stringify(diffs))
-        await Filesystem.writeJson(path.join(dir, "session", session.projectID, session.id + ".json"), {
-          ...session,
-          summary: {
-            additions: diffs.reduce((sum: any, x: any) => sum + x.additions, 0),
-            deletions: diffs.reduce((sum: any, x: any) => sum + x.deletions, 0),
-          },
-        })
+        await Bun.file(path.join(dir, "session_diff", session.id + ".json")).write(JSON.stringify(diffs))
+        await Bun.file(path.join(dir, "session", session.projectID, session.id + ".json")).write(
+          JSON.stringify({
+            ...session,
+            summary: {
+              additions: diffs.reduce((sum: any, x: any) => sum + x.additions, 0),
+              deletions: diffs.reduce((sum: any, x: any) => sum + x.deletions, 0),
+            },
+          }),
+        )
       }
     },
   ]
 
   const state = lazy(async () => {
     const dir = path.join(Global.Path.data, "storage")
-    const migration = await Filesystem.readJson<string>(path.join(dir, "migration"))
+    const migration = await Bun.file(path.join(dir, "migration"))
+      .json()
       .then((x) => parseInt(x))
       .catch(() => 0)
     for (let index = migration; index < MIGRATIONS.length; index++) {
       log.info("running migration", { index })
       const migration = MIGRATIONS[index]
       await migration(dir).catch(() => log.error("failed to run migration", { index }))
-      await Filesystem.write(path.join(dir, "migration"), (index + 1).toString())
+      await Bun.write(path.join(dir, "migration"), (index + 1).toString())
     }
     return {
       dir,
@@ -165,7 +171,7 @@ export namespace Storage {
     const target = path.join(dir, ...key) + ".json"
     return withErrorHandling(async () => {
       using _ = await Lock.read(target)
-      const result = await Filesystem.readJson<T>(target)
+      const result = await Bun.file(target).json()
       return result as T
     })
   }
@@ -175,10 +181,10 @@ export namespace Storage {
     const target = path.join(dir, ...key) + ".json"
     return withErrorHandling(async () => {
       using _ = await Lock.write(target)
-      const content = await Filesystem.readJson<T>(target)
-      fn(content as T)
-      await Filesystem.writeJson(target, content)
-      return content
+      const content = await Bun.file(target).json()
+      fn(content)
+      await Bun.write(target, JSON.stringify(content, null, 2))
+      return content as T
     })
   }
 
@@ -187,7 +193,7 @@ export namespace Storage {
     const target = path.join(dir, ...key) + ".json"
     return withErrorHandling(async () => {
       using _ = await Lock.write(target)
-      await Filesystem.writeJson(target, content)
+      await Bun.write(target, JSON.stringify(content, null, 2))
     })
   }
 
diff --git a/packages/opencode/src/tool/edit.ts b/packages/opencode/src/tool/edit.ts
index 7a097d3fe..d84f6ec34 100644
--- a/packages/opencode/src/tool/edit.ts
+++ b/packages/opencode/src/tool/edit.ts
@@ -49,7 +49,7 @@ export const EditTool = Tool.define("edit", {
     let contentNew = ""
     await FileTime.withLock(filePath, async () => {
       if (params.oldString === "") {
-        const existed = await Filesystem.exists(filePath)
+        const existed = await Bun.file(filePath).exists()
         contentNew = params.newString
         diff = trimDiff(createTwoFilesPatch(filePath, filePath, contentOld, contentNew))
         await ctx.ask({
@@ -61,7 +61,7 @@ export const EditTool = Tool.define("edit", {
             diff,
           },
         })
-        await Filesystem.write(filePath, params.newString)
+        await Bun.write(filePath, params.newString)
         await Bus.publish(File.Event.Edited, {
           file: filePath,
         })
@@ -73,11 +73,12 @@ export const EditTool = Tool.define("edit", {
         return
       }
 
-      const stats = Filesystem.stat(filePath)
+      const file = Bun.file(filePath)
+      const stats = await file.stat().catch(() => {})
       if (!stats) throw new Error(`File ${filePath} not found`)
       if (stats.isDirectory()) throw new Error(`Path is a directory, not a file: ${filePath}`)
       await FileTime.assert(ctx.sessionID, filePath)
-      contentOld = await Filesystem.readText(filePath)
+      contentOld = await file.text()
       contentNew = replace(contentOld, params.oldString, params.newString, params.replaceAll)
 
       diff = trimDiff(
@@ -93,7 +94,7 @@ export const EditTool = Tool.define("edit", {
         },
       })
 
-      await Filesystem.write(filePath, contentNew)
+      await file.write(contentNew)
       await Bus.publish(File.Event.Edited, {
         file: filePath,
       })
@@ -101,7 +102,7 @@ export const EditTool = Tool.define("edit", {
         file: filePath,
         event: "change",
       })
-      contentNew = await Filesystem.readText(filePath)
+      contentNew = await file.text()
       diff = trimDiff(
         createTwoFilesPatch(filePath, filePath, normalizeLineEndings(contentOld), normalizeLineEndings(contentNew)),
       )
diff --git a/packages/opencode/src/tool/glob.ts b/packages/opencode/src/tool/glob.ts
index a2611246c..9df1eedca 100644
--- a/packages/opencode/src/tool/glob.ts
+++ b/packages/opencode/src/tool/glob.ts
@@ -1,7 +1,6 @@
 import z from "zod"
 import path from "path"
 import { Tool } from "./tool"
-import { Filesystem } from "../util/filesystem"
 import DESCRIPTION from "./glob.txt"
 import { Ripgrep } from "../file/ripgrep"
 import { Instance } from "../project/instance"
@@ -46,7 +45,10 @@ export const GlobTool = Tool.define("glob", {
         break
       }
       const full = path.resolve(search, file)
-      const stats = Filesystem.stat(full)?.mtime.getTime() ?? 0
+      const stats = await Bun.file(full)
+        .stat()
+        .then((x) => x.mtime.getTime())
+        .catch(() => 0)
       files.push({
         path: full,
         mtime: stats,
diff --git a/packages/opencode/src/tool/grep.ts b/packages/opencode/src/tool/grep.ts
index 00497d4e3..41ed494de 100644
--- a/packages/opencode/src/tool/grep.ts
+++ b/packages/opencode/src/tool/grep.ts
@@ -1,6 +1,5 @@
 import z from "zod"
 import { Tool } from "./tool"
-import { Filesystem } from "../util/filesystem"
 import { Ripgrep } from "../file/ripgrep"
 
 import DESCRIPTION from "./grep.txt"
@@ -84,7 +83,8 @@ export const GrepTool = Tool.define("grep", {
       const lineNum = parseInt(lineNumStr, 10)
       const lineText = lineTextParts.join("|")
 
-      const stats = Filesystem.stat(filePath)
+      const file = Bun.file(filePath)
+      const stats = await file.stat().catch(() => null)
       if (!stats) continue
 
       matches.push({
diff --git a/packages/opencode/src/tool/lsp.ts b/packages/opencode/src/tool/lsp.ts
index 52aef0f9e..ca352280b 100644
--- a/packages/opencode/src/tool/lsp.ts
+++ b/packages/opencode/src/tool/lsp.ts
@@ -6,7 +6,6 @@ import DESCRIPTION from "./lsp.txt"
 import { Instance } from "../project/instance"
 import { pathToFileURL } from "url"
 import { assertExternalDirectory } from "./external-directory"
-import { Filesystem } from "../util/filesystem"
 
 const operations = [
   "goToDefinition",
@@ -48,7 +47,7 @@ export const LspTool = Tool.define("lsp", {
     const relPath = path.relative(Instance.worktree, file)
     const title = `${args.operation} ${relPath}:${args.line}:${args.character}`
 
-    const exists = await Filesystem.exists(file)
+    const exists = await Bun.file(file).exists()
     if (!exists) {
       throw new Error(`File not found: ${file}`)
     }
diff --git a/packages/opencode/src/tool/read.ts b/packages/opencode/src/tool/read.ts
index c981ac16e..80ca95900 100644
--- a/packages/opencode/src/tool/read.ts
+++ b/packages/opencode/src/tool/read.ts
@@ -10,7 +10,6 @@ import DESCRIPTION from "./read.txt"
 import { Instance } from "../project/instance"
 import { assertExternalDirectory } from "./external-directory"
 import { InstructionPrompt } from "../session/instruction"
-import { Filesystem } from "../util/filesystem"
 
 const DEFAULT_READ_LIMIT = 2000
 const MAX_LINE_LENGTH = 2000
@@ -35,7 +34,8 @@ export const ReadTool = Tool.define("read", {
     }
     const title = path.relative(Instance.worktree, filepath)
 
-    const stat = Filesystem.stat(filepath)
+    const file = Bun.file(filepath)
+    const stat = await file.stat().catch(() => undefined)
 
     await assertExternalDirectory(ctx, filepath, {
       bypass: Boolean(ctx.extra?.["bypassCwdCheck"]),
@@ -118,10 +118,11 @@ export const ReadTool = Tool.define("read", {
     const instructions = await InstructionPrompt.resolve(ctx.messages, filepath, ctx.messageID)
 
     // Exclude SVG (XML-based) and vnd.fastbidsheet (.fbs extension, commonly FlatBuffers schema files)
-    const mime = Filesystem.mimeType(filepath)
-    const isImage = mime.startsWith("image/") && mime !== "image/svg+xml" && mime !== "image/vnd.fastbidsheet"
-    const isPdf = mime === "application/pdf"
+    const isImage =
+      file.type.startsWith("image/") && file.type !== "image/svg+xml" && file.type !== "image/vnd.fastbidsheet"
+    const isPdf = file.type === "application/pdf"
     if (isImage || isPdf) {
+      const mime = file.type
       const msg = `${isImage ? "Image" : "PDF"} read successfully`
       return {
         title,
@@ -135,13 +136,13 @@ export const ReadTool = Tool.define("read", {
           {
             type: "file",
             mime,
-            url: `data:${mime};base64,${Buffer.from(await Filesystem.readBytes(filepath)).toString("base64")}`,
+            url: `data:${mime};base64,${Buffer.from(await file.bytes()).toString("base64")}`,
           },
         ],
       }
     }
 
-    const isBinary = await isBinaryFile(filepath, Number(stat.size))
+    const isBinary = await isBinaryFile(filepath, stat.size)
     if (isBinary) throw new Error(`Cannot read binary file: ${filepath}`)
 
     const stream = createReadStream(filepath, { encoding: "utf8" })
diff --git a/packages/opencode/src/tool/truncation.ts b/packages/opencode/src/tool/truncation.ts
index 4cc524aee..84e799c13 100644
--- a/packages/opencode/src/tool/truncation.ts
+++ b/packages/opencode/src/tool/truncation.ts
@@ -5,7 +5,6 @@ import { Identifier } from "../id/id"
 import { PermissionNext } from "../permission/next"
 import type { Agent } from "../agent/agent"
 import { Scheduler } from "../scheduler"
-import { Filesystem } from "../util/filesystem"
 
 export namespace Truncate {
   export const MAX_LINES = 2000
@@ -92,7 +91,7 @@ export namespace Truncate {
 
     const id = Identifier.ascending("tool")
     const filepath = path.join(DIR, id)
-    await Filesystem.write(filepath, text)
+    await Bun.write(Bun.file(filepath), text)
 
     const hint = hasTaskTool(agent)
       ? `The tool call succeeded but the output was truncated. Full output saved to: ${filepath}\nUse the Task tool to have explore agent process this file with Grep and Read (with offset/limit). Do NOT read the full file yourself - delegate to save context.`
diff --git a/packages/opencode/src/tool/write.ts b/packages/opencode/src/tool/write.ts
index 8c1e53cca..eca64d303 100644
--- a/packages/opencode/src/tool/write.ts
+++ b/packages/opencode/src/tool/write.ts
@@ -26,8 +26,9 @@ export const WriteTool = Tool.define("write", {
     const filepath = path.isAbsolute(params.filePath) ? params.filePath : path.join(Instance.directory, params.filePath)
     await assertExternalDirectory(ctx, filepath)
 
-    const exists = await Filesystem.exists(filepath)
-    const contentOld = exists ? await Filesystem.readText(filepath) : ""
+    const file = Bun.file(filepath)
+    const exists = await file.exists()
+    const contentOld = exists ? await file.text() : ""
     if (exists) await FileTime.assert(ctx.sessionID, filepath)
 
     const diff = trimDiff(createTwoFilesPatch(filepath, filepath, contentOld, params.content))
@@ -41,7 +42,7 @@ export const WriteTool = Tool.define("write", {
       },
     })
 
-    await Filesystem.write(filepath, params.content)
+    await Bun.write(filepath, params.content)
     await Bus.publish(File.Event.Edited, {
       file: filepath,
     })
diff --git a/packages/opencode/src/util/filesystem.ts b/packages/opencode/src/util/filesystem.ts
index b60b06e08..7b196eb84 100644
--- a/packages/opencode/src/util/filesystem.ts
+++ b/packages/opencode/src/util/filesystem.ts
@@ -1,10 +1,8 @@
-import { chmod, mkdir, readFile, writeFile } from "fs/promises"
-import { createWriteStream, existsSync, statSync } from "fs"
+import { mkdir, readFile, writeFile } from "fs/promises"
+import { existsSync, statSync } from "fs"
 import { lookup } from "mime-types"
 import { realpathSync } from "fs"
 import { dirname, join, relative } from "path"
-import { Readable } from "stream"
-import { pipeline } from "stream/promises"
 
 export namespace Filesystem {
   // Fast sync version for metadata checks
@@ -70,25 +68,6 @@ export namespace Filesystem {
     return write(p, JSON.stringify(data, null, 2), mode)
   }
 
-  export async function writeStream(
-    p: string,
-    stream: ReadableStream<Uint8Array> | Readable,
-    mode?: number,
-  ): Promise<void> {
-    const dir = dirname(p)
-    if (!existsSync(dir)) {
-      await mkdir(dir, { recursive: true })
-    }
-
-    const nodeStream = stream instanceof ReadableStream ? Readable.fromWeb(stream as any) : stream
-    const writeStream = createWriteStream(p)
-    await pipeline(nodeStream, writeStream)
-
-    if (mode) {
-      await chmod(p, mode)
-    }
-  }
-
   export function mimeType(p: string): string {
     return lookup(p) || "application/octet-stream"
   }
diff --git a/packages/opencode/src/util/log.ts b/packages/opencode/src/util/log.ts
index c62d59299..6941310bb 100644
--- a/packages/opencode/src/util/log.ts
+++ b/packages/opencode/src/util/log.ts
@@ -1,6 +1,5 @@
 import path from "path"
 import fs from "fs/promises"
-import { createWriteStream } from "fs"
 import { Global } from "../global"
 import z from "zod"
 
@@ -64,15 +63,13 @@ export namespace Log {
       Global.Path.log,
       options.dev ? "dev.log" : new Date().toISOString().split(".")[0].replace(/:/g, "") + ".log",
     )
+    const logfile = Bun.file(logpath)
     await fs.truncate(logpath).catch(() => {})
-    const stream = createWriteStream(logpath, { flags: "a" })
+    const writer = logfile.writer()
     write = async (msg: any) => {
-      return new Promise((resolve, reject) => {
-        stream.write(msg, (err) => {
-          if (err) reject(err)
-          else resolve(msg.length)
-        })
-      })
+      const num = writer.write(msg)
+      writer.flush()
+      return num
     }
   }
 
diff --git a/packages/opencode/test/util/filesystem.test.ts b/packages/opencode/test/util/filesystem.test.ts
index 0f5447937..3c3da0fc7 100644
--- a/packages/opencode/test/util/filesystem.test.ts
+++ b/packages/opencode/test/util/filesystem.test.ts
@@ -285,125 +285,4 @@ describe("filesystem", () => {
       expect(Filesystem.mimeType("Makefile")).toBe("application/octet-stream")
     })
   })
-
-  describe("writeStream()", () => {
-    test("writes from Web ReadableStream", async () => {
-      await using tmp = await tmpdir()
-      const filepath = path.join(tmp.path, "streamed.txt")
-      const content = "Hello from stream!"
-      const encoder = new TextEncoder()
-      const stream = new ReadableStream({
-        start(controller) {
-          controller.enqueue(encoder.encode(content))
-          controller.close()
-        },
-      })
-
-      await Filesystem.writeStream(filepath, stream)
-
-      expect(await fs.readFile(filepath, "utf-8")).toBe(content)
-    })
-
-    test("writes from Node.js Readable stream", async () => {
-      await using tmp = await tmpdir()
-      const filepath = path.join(tmp.path, "node-streamed.txt")
-      const content = "Hello from Node stream!"
-      const { Readable } = await import("stream")
-      const stream = Readable.from([content])
-
-      await Filesystem.writeStream(filepath, stream)
-
-      expect(await fs.readFile(filepath, "utf-8")).toBe(content)
-    })
-
-    test("writes binary data from Web ReadableStream", async () => {
-      await using tmp = await tmpdir()
-      const filepath = path.join(tmp.path, "binary.dat")
-      const binaryData = new Uint8Array([0x00, 0x01, 0x02, 0x03, 0xff])
-      const stream = new ReadableStream({
-        start(controller) {
-          controller.enqueue(binaryData)
-          controller.close()
-        },
-      })
-
-      await Filesystem.writeStream(filepath, stream)
-
-      const read = await fs.readFile(filepath)
-      expect(Buffer.from(read)).toEqual(Buffer.from(binaryData))
-    })
-
-    test("writes large content in chunks", async () => {
-      await using tmp = await tmpdir()
-      const filepath = path.join(tmp.path, "large.txt")
-      const chunks = ["chunk1", "chunk2", "chunk3", "chunk4", "chunk5"]
-      const stream = new ReadableStream({
-        start(controller) {
-          for (const chunk of chunks) {
-            controller.enqueue(new TextEncoder().encode(chunk))
-          }
-          controller.close()
-        },
-      })
-
-      await Filesystem.writeStream(filepath, stream)
-
-      expect(await fs.readFile(filepath, "utf-8")).toBe(chunks.join(""))
-    })
-
-    test("creates parent directories", async () => {
-      await using tmp = await tmpdir()
-      const filepath = path.join(tmp.path, "nested", "deep", "streamed.txt")
-      const content = "nested stream content"
-      const stream = new ReadableStream({
-        start(controller) {
-          controller.enqueue(new TextEncoder().encode(content))
-          controller.close()
-        },
-      })
-
-      await Filesystem.writeStream(filepath, stream)
-
-      expect(await fs.readFile(filepath, "utf-8")).toBe(content)
-    })
-
-    test("writes with permissions", async () => {
-      await using tmp = await tmpdir()
-      const filepath = path.join(tmp.path, "protected-stream.txt")
-      const content = "secret stream content"
-      const stream = new ReadableStream({
-        start(controller) {
-          controller.enqueue(new TextEncoder().encode(content))
-          controller.close()
-        },
-      })
-
-      await Filesystem.writeStream(filepath, stream, 0o600)
-
-      const stats = await fs.stat(filepath)
-      if (process.platform !== "win32") {
-        expect(stats.mode & 0o777).toBe(0o600)
-      }
-    })
-
-    test("writes executable with permissions", async () => {
-      await using tmp = await tmpdir()
-      const filepath = path.join(tmp.path, "script.sh")
-      const content = "#!/bin/bash\necho hello"
-      const stream = new ReadableStream({
-        start(controller) {
-          controller.enqueue(new TextEncoder().encode(content))
-          controller.close()
-        },
-      })
-
-      await Filesystem.writeStream(filepath, stream, 0o755)
-
-      const stats = await fs.stat(filepath)
-      if (process.platform !== "win32") {
-        expect(stats.mode & 0o777).toBe(0o755)
-      }
-      expect(await fs.readFile(filepath, "utf-8")).toBe(content)
-    })
-  })
 })