diff --git a/packages/opencode/src/cli/cmd/serve.ts b/packages/opencode/src/cli/cmd/serve.ts
index 657f9196c96..f2ef44945ae 100644
--- a/packages/opencode/src/cli/cmd/serve.ts
+++ b/packages/opencode/src/cli/cmd/serve.ts
@@ -1,14 +1,21 @@
 import { Server } from "../../server/server"
 import { cmd } from "./cmd"
 import { withNetworkOptions, resolveNetworkOptions } from "../network"
+import path from "path"
 
 export const ServeCommand = cmd({
   command: "serve",
-  builder: (yargs) => withNetworkOptions(yargs),
+  builder: (yargs) =>
+    withNetworkOptions(yargs).option("cwd", {
+      describe: "working directory",
+      type: "string",
+    }),
   describe: "starts a headless opencode server",
   handler: async (args) => {
     const opts = await resolveNetworkOptions(args)
-    const server = Server.listen(opts)
+    const base = process.env.PWD ?? process.cwd()
+    const cwd = args.cwd ? path.resolve(base, args.cwd) : undefined
+    const server = Server.listen({ ...opts, directory: cwd })
     console.log(`opencode server listening on http://${server.hostname}:${server.port}`)
     await new Promise(() => {})
     await server.stop()
diff --git a/packages/opencode/src/project/instance.ts b/packages/opencode/src/project/instance.ts
index d668037c016..882e03c3271 100644
--- a/packages/opencode/src/project/instance.ts
+++ b/packages/opencode/src/project/instance.ts
@@ -14,12 +14,12 @@ const context = Context.create<Context>("instance")
 const cache = new Map<string, Promise<Context>>()
 
 export const Instance = {
-  async provide<R>(input: { directory: string; init?: () => Promise<any>; fn: () => R }): Promise<R> {
+  async provide<R>(input: { directory: string; root?: string; init?: () => Promise<any>; fn: () => R }): Promise<R> {
     let existing = cache.get(input.directory)
     if (!existing) {
       Log.Default.info("creating instance", { directory: input.directory })
       existing = iife(async () => {
-        const { project, sandbox } = await Project.fromDirectory(input.directory)
+        const { project, sandbox } = await Project.fromDirectory(input.directory, { root: input.root })
         const ctx = {
           directory: input.directory,
           worktree: sandbox,
diff --git a/packages/opencode/src/project/project.ts b/packages/opencode/src/project/project.ts
index 35fdd4717b2..56a7067984f 100644
--- a/packages/opencode/src/project/project.ts
+++ b/packages/opencode/src/project/project.ts
@@ -16,6 +16,9 @@ import { existsSync } from "fs"
 
 export namespace Project {
   const log = Log.create({ service: "project" })
+  type Root = {
+    root?: string
+  }
   export const Info = z
     .object({
       id: z.string(),
@@ -44,8 +47,9 @@ export namespace Project {
     Updated: BusEvent.define("project.updated", Info),
   }
 
-  export async function fromDirectory(directory: string) {
-    log.info("fromDirectory", { directory })
+  export async function fromDirectory(directory: string, input?: Root) {
+    const root = input?.root ? path.resolve(input.root) : undefined
+    log.info("fromDirectory", { directory, root })
 
     const { id, sandbox, worktree, vcs } = await iife(async () => {
       const matches = Filesystem.up({ targets: [".git"], start: directory })
@@ -161,6 +165,16 @@ export namespace Project {
         }
       }
 
+      if (root) {
+        const id = `root-${Bun.hash.xxHash32(root)}`
+        return {
+          id,
+          worktree: root,
+          sandbox: root,
+          vcs: Info.shape.vcs.parse(Flag.OPENCODE_FAKE_VCS),
+        }
+      }
+
       return {
         id: "global",
         worktree: "/",
diff --git a/packages/opencode/src/server/server.ts b/packages/opencode/src/server/server.ts
index 04ec4673ec4..cf7b3acbb67 100644
--- a/packages/opencode/src/server/server.ts
+++ b/packages/opencode/src/server/server.ts
@@ -60,6 +60,8 @@ export namespace Server {
 
   let _url: URL | undefined
   let _corsWhitelist: string[] = []
+  let _defaultDirectory: string | undefined
+  let _defaultRoot: string | undefined
 
   export function url(): URL {
     return _url ?? new URL("http://localhost:4096")
@@ -246,9 +248,13 @@ export namespace Server {
         },
       )
       .use(async (c, next) => {
-        const directory = c.req.query("directory") || c.req.header("x-opencode-directory") || process.cwd()
+        const queryDirectory = c.req.query("directory")
+        const headerDirectory = c.req.header("x-opencode-directory")
+        const directory = queryDirectory || headerDirectory || _defaultDirectory || process.cwd()
+        const root = queryDirectory || headerDirectory ? directory : _defaultRoot
         return Instance.provide({
           directory,
+          root,
           init: InstanceBootstrap,
           async fn() {
             return next()
@@ -2829,8 +2835,10 @@ export namespace Server {
     return result
   }
 
-  export function listen(opts: { port: number; hostname: string; mdns?: boolean; cors?: string[] }) {
+  export function listen(opts: { port: number; hostname: string; mdns?: boolean; cors?: string[]; directory?: string }) {
     _corsWhitelist = opts.cors ?? []
+    _defaultDirectory = opts.directory ?? process.cwd()
+    _defaultRoot = opts.directory ? _defaultDirectory : undefined
 
     const args = {
       hostname: opts.hostname,
diff --git a/packages/sdk/js/src/server.ts b/packages/sdk/js/src/server.ts
index 174131ccfd5..d2dc0a5369f 100644
--- a/packages/sdk/js/src/server.ts
+++ b/packages/sdk/js/src/server.ts
@@ -6,6 +6,7 @@ export type ServerOptions = {
   port?: number
   signal?: AbortSignal
   timeout?: number
+  cwd?: string
   config?: Config
 }
 
@@ -29,6 +30,7 @@ export async function createOpencodeServer(options?: ServerOptions) {
   )
 
   const args = [`serve`, `--hostname=${options.hostname}`, `--port=${options.port}`]
+  if (options.cwd) args.push(`--cwd=${options.cwd}`)
   if (options.config?.logLevel) args.push(`--log-level=${options.config.logLevel}`)
 
   const proc = spawn(`opencode`, args, {
diff --git a/packages/sdk/js/src/v2/server.ts b/packages/sdk/js/src/v2/server.ts
index 174131ccfd5..d2dc0a5369f 100644
--- a/packages/sdk/js/src/v2/server.ts
+++ b/packages/sdk/js/src/v2/server.ts
@@ -6,6 +6,7 @@ export type ServerOptions = {
   port?: number
   signal?: AbortSignal
   timeout?: number
+  cwd?: string
   config?: Config
 }
 
@@ -29,6 +30,7 @@ export async function createOpencodeServer(options?: ServerOptions) {
   )
 
   const args = [`serve`, `--hostname=${options.hostname}`, `--port=${options.port}`]
+  if (options.cwd) args.push(`--cwd=${options.cwd}`)
   if (options.config?.logLevel) args.push(`--log-level=${options.config.logLevel}`)
 
   const proc = spawn(`opencode`, args, {