test(cli): prove every target build leaves model selection to the host

cli/tests/e2e/framework-model-inheritance.e2e.test.ts

@@ -0,0 +1,50 @@
+import { mkdir, readdir, readFile } from "node:fs/promises";
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+import { frameworkBuildTargetModes } from "../../src/contexts/translate/domain/build-target.js";
+import "../../src/runtime/wiring/translate.js";
+import { REPOSITORY_ROOT } from "../helpers/repository-root.js";
+import { createTestEnv, runCli } from "./helpers.js";
+
+// Every target/mode the CLI announces, built from the shipped plugins rather than a fixture.
+const CELLS = frameworkBuildTargetModes();
+
+// A recipe may show a model in an example block; only a declaration the host reads counts.
+function overridesModel(path: string, content: string): boolean {
+  if (path.endsWith(".toml")) return /^model\s*=/m.test(content);
+  const frontmatter = content.match(/^---\r?\n([\s\S]*?)\r?\n---/);
+  return frontmatter !== null && /^model\s*:/m.test(frontmatter[1]);
+}
+
+describe.concurrent("E2E: the shipped framework leaves model selection to the host", () => {
+  it.each(CELLS)(
+    "$target $mode emits no model override",
+    async ({ target, mode }) => {
+      const { tempDir, projectDir, fakeHome, cleanup } = await createTestEnv(
+        `model-${target}-${mode}`
+      );
+      try {
+        const outDir = join(tempDir, "dist");
+        await mkdir(outDir, { recursive: true });
+        const args = ["translate", REPOSITORY_ROOT, "--to", target, "--out", outDir, "--as", mode];
+        const build = await runCli(args, projectDir, fakeHome);
+        expect(build.exitCode, build.stderr).toBe(0);
+
+        const files = await readdir(outDir, { recursive: true, withFileTypes: true });
+        const emitted = files.filter((entry) => entry.isFile());
+        expect(emitted.length).toBeGreaterThan(0);
+        const overrides: string[] = [];
+        for (const entry of emitted) {
+          const path = join(entry.parentPath, entry.name);
+          if (overridesModel(path, await readFile(path, "utf-8"))) {
+            overrides.push(path.slice(outDir.length));
+          }
+        }
+        expect(overrides).toEqual([]);
+      } finally {
+        await cleanup();
+      }
+    },
+    120_000
+  );
+});

docs/ARCHITECTURE.md

@@ -125,6 +125,7 @@ Dependency-free Node scripts declared in `hooks/hooks.json`; `node` must be on `
 | Skills | Links stay inside the skill directory. Flat distribution renames skills `<plugin>-<skill>`; marketplace installation preserves the tree. | [Portability guard](../scripts/__tests__/a-skill-links-only-inside-itself.test.js) |
 | Bundled scripts | Named plugin-relative in backticks, never linked. | [Portability guard](../scripts/__tests__/a-skill-links-only-inside-itself.test.js) |
 | Hook adapters | CLI owns OpenCode's shared host protocol; plugins own payload mapping. | [Delivery and compatibility](../cli/ARCHITECTURE.md#hook-adaptation) |
+| Model selection | The user and host own the concrete model and reasoning settings; no shipped skill or agent pins one, and a target build carries over a model the user wrote only where the target supports one. | [Source guard](../scripts/__tests__/model-selection.test.js) · [Build guard](../cli/tests/e2e/framework-model-inheritance.e2e.test.ts) |
 
 ## Capability discovery and addressing