fix(server): don't forward host directory to remote workspace (#40136)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

packages/opencode/src/server/shared/workspace-routing.ts

@@ -34,5 +34,12 @@ export function workspaceProxyURL(target: string | URL, requestURL: URL) {
   proxyURL.search = requestURL.search
   proxyURL.hash = requestURL.hash
   proxyURL.searchParams.delete("workspace")
+  // The `directory` param is the *host's* working directory (e.g. a Windows
+  // path like `F:\proj`). It is meaningless — and dangerous — on the remote:
+  // the sandbox would `path.resolve` it against its own cwd, producing a bogus
+  // path like `/home/daytona/workspace/repo/F:\proj` that does not exist and
+  // crashes prompt handling. Drop it so the remote falls back to its own
+  // project root. This mirrors ProxyUtil.headers stripping `x-opencode-directory`.
+  proxyURL.searchParams.delete("directory")
   return proxyURL
 }

packages/opencode/test/server/workspace-routing.test.ts

@@ -80,6 +80,13 @@ describe("workspaceProxyURL", () => {
     expect(result.searchParams.get("keep")).toBe("yes")
   })
 
+  test("strips the host directory param so the remote resolves its own root", () => {
+    const url = new URL("http://localhost/session/abc?directory=F%3A%5Cproj&keep=yes")
+    const result = workspaceProxyURL("http://remote:8080/base", url)
+    expect(result.searchParams.get("directory")).toBeNull()
+    expect(result.searchParams.get("keep")).toBe("yes")
+  })
+
   test("preserves hash from request", () => {
     const url = new URL("http://localhost/page#section")
     const result = workspaceProxyURL("http://remote:8080", url)