refactor(core): extract composer model policy

Generated-By: PostHog Code
Task-Id: c1bbe3cf-742b-4b24-bf96-d11a18b4cf22

Author: richardsolomou

packages/core/src/task-detail/composerModelPolicy.test.ts

@@ -0,0 +1,42 @@
+import {
+  type Adapter,
+  type CloudTaskConfigOption,
+  DEFAULT_GATEWAY_MODEL,
+  restrictedModelMeta,
+  type SupportedReasoningEffort,
+} from "@posthog/shared";
+import { expect, it } from "vitest";
+import { resolveCloudComposerModelChange } from "./composerModelPolicy";
+
+const modelOption: CloudTaskConfigOption = {
+  id: "model",
+  name: "Model",
+  type: "select",
+  currentValue: DEFAULT_GATEWAY_MODEL,
+  options: [
+    { value: DEFAULT_GATEWAY_MODEL, name: "Claude" },
+    { value: "restricted", name: "Restricted", _meta: restrictedModelMeta() },
+    { value: "gpt-5.3-codex", name: "Codex" },
+  ],
+  category: "model",
+  description: "Choose a model",
+};
+
+it.each([
+  ["claude", DEFAULT_GATEWAY_MODEL, "high", DEFAULT_GATEWAY_MODEL, "high"],
+  ["claude", "restricted", "high", DEFAULT_GATEWAY_MODEL, "high"],
+  ["claude", "missing", "high", DEFAULT_GATEWAY_MODEL, "high"],
+  ["codex", "gpt-5.3-codex", "xhigh", "gpt-5.3-codex", "high"],
+] as const)(
+  "resolves %s model %s with %s reasoning",
+  (adapter, requestedModel, reasoning, expectedModel, expectedReasoning) => {
+    expect(
+      resolveCloudComposerModelChange({
+        adapter: adapter as Adapter,
+        modelOption,
+        requestedModel,
+        reasoning: reasoning as SupportedReasoningEffort,
+      }),
+    ).toEqual({ model: expectedModel, reasoning: expectedReasoning });
+  },
+);

packages/core/src/task-detail/composerModelPolicy.ts

@@ -0,0 +1,35 @@
+import {
+  type Adapter,
+  type CloudTaskConfigOption,
+  DEFAULT_REASONING_EFFORT,
+  isRestrictedModelOption,
+  isSupportedReasoningEffort,
+  type SupportedReasoningEffort,
+} from "@posthog/shared";
+
+export function resolveCloudComposerModelChange({
+  adapter,
+  modelOption,
+  requestedModel,
+  reasoning,
+}: {
+  adapter: Adapter;
+  modelOption: CloudTaskConfigOption;
+  requestedModel: string;
+  reasoning: SupportedReasoningEffort;
+}): { model: string; reasoning: SupportedReasoningEffort } {
+  const selected = modelOption.options.find(
+    (option) => option.value === requestedModel,
+  );
+  const model =
+    selected && !isRestrictedModelOption(selected._meta)
+      ? requestedModel
+      : modelOption.currentValue;
+
+  return {
+    model,
+    reasoning: isSupportedReasoningEffort(adapter, model, reasoning)
+      ? reasoning
+      : DEFAULT_REASONING_EFFORT,
+  };
+}