feat: add claw backend adapter

tests/execution-backend-selector.test.ts

@@ -1,6 +1,9 @@
 import assert from "node:assert/strict";
 import test from "node:test";
-import { selectExecutionBackendForTesting } from "@/lib/execution/backend-selector";
+import {
+  listExecutionBackendChoices,
+  selectExecutionBackendForTesting,
+} from "@/lib/execution/backend-selector";
 
 test("selectExecutionBackendForTesting prefers the ready primary master codex node", async () => {
   const backend = await selectExecutionBackendForTesting({
@@ -73,3 +76,46 @@ test("selectExecutionBackendForTesting falls back to master node last when highe
 
   assert.equal(backend.backendId, "master-codex-node");
 });
+
+test("listExecutionBackendChoices keeps claw disabled by default", () => {
+  const backends = listExecutionBackendChoices({
+    primary: { provider: "master_codex_node", status: "ready" },
+    backups: [{ provider: "openai_api", status: "ready" }],
+    requestKind: "master_agent_reply",
+  });
+
+  assert.deepEqual(
+    backends.map((backend) => backend.backendId),
+    ["master-codex-node", "openai-api"],
+  );
+});
+
+test("selectExecutionBackendForTesting honors an explicit claw request when claw is enabled", async () => {
+  const backend = await selectExecutionBackendForTesting({
+    primary: { provider: "master_codex_node", status: "ready" },
+    backups: [{ provider: "openai_api", status: "ready" }],
+    requestKind: "master_agent_reply",
+    requestedBackendId: "claw-runtime",
+    claw: {
+      enabled: true,
+      supportsKinds: ["master_agent_reply", "thread_reply"],
+    },
+  });
+
+  assert.equal(backend.backendId, "claw-runtime");
+});
+
+test("selectExecutionBackendForTesting falls back when claw is requested but unavailable", async () => {
+  const backend = await selectExecutionBackendForTesting({
+    primary: { provider: "master_codex_node", status: "ready" },
+    backups: [{ provider: "openai_api", status: "ready" }],
+    requestKind: "master_agent_reply",
+    requestedBackendId: "claw-runtime",
+    claw: {
+      enabled: false,
+      supportsKinds: ["master_agent_reply"],
+    },
+  });
+
+  assert.equal(backend.backendId, "master-codex-node");
+});