diff --git a/packages/opencode/src/lsp/server.ts b/packages/opencode/src/lsp/server.ts
index 7102d0d8ed3e..97977435ddd1 100644
--- a/packages/opencode/src/lsp/server.ts
+++ b/packages/opencode/src/lsp/server.ts
@@ -1881,10 +1881,10 @@ export namespace LSPServer {
     async spawn(root) {
       const bin = which("LSPServer") ?? (process.platform === "win32" ? which("LSPServer.exe") : null)
       if (!bin) {
-        log.info("LSPServer not found, please install CangjieSDK first")
+        log.info("LSPServer not found, please install Cangjie SDK and source envsetup.sh first")
         return
       }
-      const proc = spawn(bin, [], {
+      const proc = spawn(bin, ["--stdio"], {
         cwd: root,
       })
       proc.on("error", (err) => {
diff --git a/packages/opencode/test/lsp/cangjie-server.test.ts b/packages/opencode/test/lsp/cangjie-server.test.ts
new file mode 100644
index 000000000000..ddb83600331d
--- /dev/null
+++ b/packages/opencode/test/lsp/cangjie-server.test.ts
@@ -0,0 +1,46 @@
+import { describe, expect, test, beforeEach } from "bun:test"
+import path from "path"
+import { spawn } from "child_process"
+import { LSPClient } from "../../src/lsp/client"
+import { LSPServer } from "../../src/lsp/server"
+import { Instance } from "../../src/project/instance"
+import { Log } from "../../src/util/log"
+
+function spawnFakeServer() {
+  const serverPath = path.join(__dirname, "../fixture/lsp/fake-lsp-server.js")
+  return {
+    process: spawn(process.execPath, [serverPath], {
+      stdio: "pipe",
+    }),
+  }
+}
+
+describe("Cangjie LSP server", () => {
+  beforeEach(async () => {
+    await Log.init({ print: true })
+  })
+
+  test("config has correct id and extensions", () => {
+    const info = LSPServer.Cangjie
+    expect(info.id).toBe("cangjie")
+    expect(info.extensions).toEqual([".cj"])
+  })
+
+  test("initializes over stdio", async () => {
+    const handle = spawnFakeServer()
+
+    const client = await Instance.provide({
+      directory: process.cwd(),
+      fn: () =>
+        LSPClient.create({
+          serverID: "cangjie",
+          server: handle as unknown as LSPServer.Handle,
+          root: process.cwd(),
+        }),
+    })
+
+    expect(client.connection).toBeDefined()
+
+    await client.shutdown()
+  })
+})