feat: add Handlebars template engine with peer-aware render context and consolidate eslint-prettier into a single adaptive template

- Replace per-framework template files (`eslint.config.next.mjs`, `eslint.config.tanstack.mjs`) with a single `eslint.config.mjs` that branches via Handlebars `{{#if peers.framework}}` conditionals; add `handlebars` as a direct dependency to `@stanza/registry`, `apps/cli`, and `apps/web`
- Extend the template render context with a `peers: Partial<Record<CategoryId, string>>` map so any template can inspect the active framework, auth provider, etc.; thread it through `buildRenderContext`, `synthesizeTemplates`, the CLI `codemod-runner`, and the web `getBuilderState` server function
- Extract and export `activePeerIds(manifest, appId?)` from `@stanza/registry` to derive the peer map from a manifest (app-scoped for `home: app` categories); add `selectedPeerIds(selections)` in `apps/web/src/lib/selection.ts` as the URL-params-derived equivalent
- Add integration tests verifying framework-conditional eslint-prettier output for `default`, `next`, and `tanstack-start` adapters; expand resolver tests for `activePeerIds` app-scoping and for modules that declare both a `default` adapter and a framework-specific override

apps/cli/package.json

@@ -48,6 +48,7 @@
   "dependencies": {
     "@clack/prompts": "^1.4.0",
     "citty": "^0.2.2",
+    "handlebars": "^4.7.9",
     "picocolors": "^1.1.1",
     "semver": "^7.8.1",
     "ts-morph": "^28.0.0",

apps/cli/src/commands/commands.test.ts

@@ -330,3 +330,91 @@ describe("tooling slot (single-choice, repo-scoped)", () => {
     expect(manifest.modules.tooling[0].id).toBe("biome");
   });
 });
+
+describe("tooling-eslint-prettier — framework-conditional rendering", () => {
+  it("installs without a framework via the default adapter (pure-TS config)", async () => {
+    await cmdInit(args({ name: "app", yes: true, tooling: "eslint-prettier" }));
+    expect(process.exitCode).toBeFalsy();
+
+    const projectRoot = path.join(tmp, "app");
+    const manifest = JSON.parse(fs.readFileSync(path.join(projectRoot, "stanza.json"), "utf8"));
+    expect(manifest.modules.tooling?.[0]).toMatchObject({
+      id: "eslint-prettier",
+      adapter: "default",
+    });
+
+    const config = fs.readFileSync(path.join(projectRoot, "eslint.config.mjs"), "utf8");
+    // Framework-specific blocks must be absent.
+    expect(config).not.toContain("@next/eslint-plugin-next");
+    expect(config).not.toContain("eslint-plugin-react");
+    expect(config).not.toContain("core-web-vitals");
+    expect(config).not.toContain(".next");
+    expect(config).not.toContain("routeTree.gen.ts");
+    // Pure-TS base is still present.
+    expect(config).toContain('import tseslint from "typescript-eslint";');
+    expect(config).toContain('import prettier from "eslint-config-prettier";');
+
+    const rootPkg = JSON.parse(fs.readFileSync(path.join(projectRoot, "package.json"), "utf8"));
+    expect(rootPkg.devDependencies.eslint).toBeTruthy();
+    expect(rootPkg.devDependencies["@next/eslint-plugin-next"]).toBeUndefined();
+    expect(rootPkg.devDependencies["eslint-plugin-react"]).toBeUndefined();
+    expect(rootPkg.devDependencies["eslint-plugin-react-hooks"]).toBeUndefined();
+  });
+
+  it("layers Next-specific plugins when framework=next", async () => {
+    await cmdInit(args({ name: "app", yes: true, framework: "next", tooling: "eslint-prettier" }));
+    expect(process.exitCode).toBeFalsy();
+
+    const projectRoot = path.join(tmp, "app");
+    const manifest = JSON.parse(fs.readFileSync(path.join(projectRoot, "stanza.json"), "utf8"));
+    expect(manifest.modules.tooling?.[0]).toMatchObject({
+      id: "eslint-prettier",
+      adapter: "next",
+    });
+
+    const config = fs.readFileSync(path.join(projectRoot, "eslint.config.mjs"), "utf8");
+    expect(config).toContain('import next from "@next/eslint-plugin-next";');
+    expect(config).toContain("core-web-vitals");
+    expect(config).toContain("**/.next/**");
+    // TanStack-specific bits must not leak in.
+    expect(config).not.toContain('import react from "eslint-plugin-react";');
+    expect(config).not.toContain("routeTree.gen.ts");
+
+    const rootPkg = JSON.parse(fs.readFileSync(path.join(projectRoot, "package.json"), "utf8"));
+    expect(rootPkg.devDependencies["@next/eslint-plugin-next"]).toBeTruthy();
+    expect(rootPkg.devDependencies["eslint-plugin-react-hooks"]).toBeTruthy();
+    expect(rootPkg.devDependencies["eslint-plugin-react"]).toBeUndefined();
+  });
+
+  it("layers TanStack-specific plugins when framework=tanstack-start", async () => {
+    await cmdInit(
+      args({
+        name: "app",
+        yes: true,
+        framework: "tanstack-start",
+        tooling: "eslint-prettier",
+      }),
+    );
+    expect(process.exitCode).toBeFalsy();
+
+    const projectRoot = path.join(tmp, "app");
+    const manifest = JSON.parse(fs.readFileSync(path.join(projectRoot, "stanza.json"), "utf8"));
+    expect(manifest.modules.tooling?.[0]).toMatchObject({
+      id: "eslint-prettier",
+      adapter: "tanstack-start",
+    });
+
+    const config = fs.readFileSync(path.join(projectRoot, "eslint.config.mjs"), "utf8");
+    expect(config).toContain('import react from "eslint-plugin-react";');
+    expect(config).toContain("routeTree.gen.ts");
+    expect(config).toContain("react/react-in-jsx-scope");
+    // Next-specific bits must not leak in.
+    expect(config).not.toContain("@next/eslint-plugin-next");
+    expect(config).not.toContain("core-web-vitals");
+
+    const rootPkg = JSON.parse(fs.readFileSync(path.join(projectRoot, "package.json"), "utf8"));
+    expect(rootPkg.devDependencies["eslint-plugin-react"]).toBeTruthy();
+    expect(rootPkg.devDependencies["eslint-plugin-react-hooks"]).toBeTruthy();
+    expect(rootPkg.devDependencies["@next/eslint-plugin-next"]).toBeUndefined();
+  });
+});

apps/cli/src/lib/codemod-runner.ts

@@ -15,6 +15,7 @@ import type {
   TemplateRef,
 } from "@stanza/registry";
 import {
+  activePeerIds,
   buildRenderContext,
   categoryHome,
   installPackageJsonTargets,
@@ -122,11 +123,14 @@ export async function applyModule(args: {
   // the active target so a module shipped into multiple apps renders correctly
   // per app. `seedApp` covers repo/package-scoped templates — they don't
   // reference `app.*` but `buildRenderContext` still needs a valid `AppSpec`.
+  // Peers are resolved per-app so app-scoped templates see the right framework
+  // (e.g. web's framework vs native's) when conditionally branching.
   const renderContextFor = (app: AppSpec): TemplateContext =>
     buildRenderContext({
       projectName: manifest.name,
       app,
       packageName,
+      peers: activePeerIds(manifest, app.id),
     });
   const seedApp = targetApps[0]!;
 
@@ -593,6 +597,7 @@ export async function revertCodemods(args: {
       projectName: manifest.name,
       app,
       packageName,
+      peers: activePeerIds(manifest, app.id),
     });
     const project = lazyProject(appRoot);
     const ctx = buildContext({

apps/web/package.json

@@ -20,20 +20,21 @@
     "@stanza/registry": "workspace:*",
     "@tabler/icons-react": "^3.44.0",
     "@tailwindcss/vite": "^4.3.0",
-    "@takumi-rs/image-response": "^1.4.1",
+    "@takumi-rs/image-response": "^1.5.1",
     "@tanstack/react-devtools": "^0.10.5",
     "@tanstack/react-hotkeys": "^0.10.0",
-    "@tanstack/react-router": "^1.170.7",
+    "@tanstack/react-router": "^1.170.8",
     "@tanstack/react-router-devtools": "^1.167.0",
     "@tanstack/react-router-ssr-query": "^1.167.0",
-    "@tanstack/react-start": "^1.168.10",
-    "@tanstack/router-plugin": "^1.168.10",
+    "@tanstack/react-start": "^1.168.13",
+    "@tanstack/router-plugin": "^1.168.11",
     "@vercel/functions": "^3.6.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "fumadocs-core": "^16.9.1",
     "fumadocs-mdx": "^15.0.8",
     "fumadocs-ui": "npm:@fumadocs/base-ui@^16.9.1",
+    "handlebars": "^4.7.9",
     "lru-cache": "^11.5.0",
     "nitro": "^3.0.260522-beta",
     "posthog-js": "^1.376.0",

apps/web/src/lib/selection.ts

@@ -93,6 +93,21 @@ function pendingPeers(
   return pending;
 }
 
+/**
+ * Active peer ids — the URL-derived equivalent of the CLI runner's
+ * `activePeerIds(manifest, app.id)`. Single source of truth for what
+ * `synthesizeTemplates` should expose under `{{peers.<category>}}` in the
+ * Handlebars render context.
+ */
+export function selectedPeerIds(selections: Selections): Partial<Record<CategoryId, string>> {
+  const out: Partial<Record<CategoryId, string>> = {};
+  for (const category of PEER_CATEGORIES) {
+    const id = selections[category]?.[0];
+    if (id) out[category] = id;
+  }
+  return out;
+}
+
 /**
  * Resolve each selected module's adapter against the chosen one-cardinality
  * peers — the same logic the CLI uses. Modules whose peers aren't satisfied are

apps/web/src/server/builder-state.functions.ts

@@ -7,7 +7,12 @@ import {
 } from "@stanza/registry";
 import { createServerFn } from "@tanstack/react-start";
 
-import { DEFAULT_BUILDER_APPS, parseSelections, resolveSelected } from "@/lib/selection";
+import {
+  DEFAULT_BUILDER_APPS,
+  parseSelections,
+  resolveSelected,
+  selectedPeerIds,
+} from "@/lib/selection";
 import type { BuilderSearch } from "@/lib/selection";
 import type { Preview } from "@/server/highlighter";
 import { getHighlighter, renderPreview } from "@/server/highlighter.server";
@@ -47,6 +52,7 @@ export const getBuilderState = createServerFn({ method: "GET" })
 
     const { name, pm, selections } = parseSelections(data);
     const resolved = resolveSelected(modules, selections);
+    const peers = selectedPeerIds(selections);
 
     // Templates carry their own content; package.json, stanza.json, and
     // .env.example are synthesized — the CLI never ships them as templates, it
@@ -61,6 +67,7 @@ export const getBuilderState = createServerFn({ method: "GET" })
     const previewFiles: { path: string; content: string }[] = synthesizeTemplates(resolved, {
       name,
       apps,
+      peers,
     }).map((tpl) => ({ path: tpl.path, content: tpl.content }));
     if (hasSelection) {
       const pkgJsons = synthesizePackageJsons(resolved, { name, apps, packageManager: pm });

package.json

@@ -25,6 +25,7 @@
     "@changesets/cli": "^2.31.0",
     "@stanza/registry": "workspace:*",
     "@types/node": "^25.9.1",
+    "jiti": "^2.7.0",
     "typescript": "^6.0.3",
     "vite-plus": "catalog:"
   },

packages/registry/package.json

@@ -13,6 +13,7 @@
     "./resolver": "./src/resolver.ts"
   },
   "dependencies": {
+    "handlebars": "^4.7.9",
     "validate-npm-package-name": "^8.0.0",
     "zod": "^4.4.3"
   },

packages/registry/src/index.ts

@@ -54,7 +54,7 @@ export {
 } from "./manifest";
 
 export type { ResolveContext, ResolveResult, ResolveError } from "./resolver";
-export { resolveAdapter, isCompatible, categoryOrder } from "./resolver";
+export { resolveAdapter, isCompatible, categoryOrder, activePeerIds } from "./resolver";
 
 export type {
   PackageManager,

packages/registry/src/resolver.test.ts

@@ -2,7 +2,7 @@ import { assert, describe, expect, it } from "vite-plus/test";
 
 import { emptyManifest } from "./manifest";
 import { defineModule, type Module } from "./module";
-import { resolveAdapter } from "./resolver";
+import { activePeerIds, resolveAdapter } from "./resolver";
 
 const drizzle: Module = defineModule({
   id: "drizzle",
@@ -156,3 +156,69 @@ describe("resolveAdapter — add-ons", () => {
     expect(result.error.kind).toBe("missing-peer");
   });
 });
+
+// Module with both a generic default and a framework-specific override —
+// mirrors the tooling-eslint-prettier shape after its standalone refactor.
+const eslintLike: Module = defineModule({
+  id: "eslint-like",
+  category: "tooling",
+  label: "ESLint-like",
+  description: "",
+  version: "0.1.0",
+  adapters: [
+    { key: "next", match: { framework: "next" } },
+    { key: "default", match: {} },
+  ],
+});
+
+describe("resolveAdapter — default + framework-specific adapters coexist", () => {
+  it("picks the framework-specific adapter when its peer is active", () => {
+    const result = resolveAdapter(eslintLike, {
+      manifest: emptyManifest({ name: "t" }),
+      pending: { framework: next },
+    });
+    expect(result.ok).toBe(true);
+    assert(result.ok);
+    expect(result.adapter.key).toBe("next");
+  });
+
+  it("falls back to the empty-match default when no framework is selected", () => {
+    const result = resolveAdapter(eslintLike, {
+      manifest: emptyManifest({ name: "t" }),
+      pending: {},
+    });
+    expect(result.ok).toBe(true);
+    assert(result.ok);
+    expect(result.adapter.key).toBe("default");
+  });
+});
+
+describe("activePeerIds", () => {
+  it("returns an empty record for a manifest with no selections", () => {
+    expect(activePeerIds(emptyManifest({ name: "t" }))).toEqual({});
+  });
+
+  it("reads the installed framework id from the manifest", () => {
+    const manifest = {
+      ...emptyManifest({ name: "t" }),
+      modules: {
+        framework: [{ id: "next", version: "0.1.0", adapter: "default", apps: ["web"] }],
+      },
+    };
+    expect(activePeerIds(manifest, "web")).toEqual({ framework: "next" });
+  });
+
+  it("scopes app-home peer lookups to the targetAppId", () => {
+    const manifest = {
+      ...emptyManifest({ name: "t" }),
+      modules: {
+        framework: [
+          { id: "next", version: "0.1.0", adapter: "default", apps: ["web"] },
+          { id: "expo", version: "0.1.0", adapter: "default", apps: ["native"] },
+        ],
+      },
+    };
+    expect(activePeerIds(manifest, "web").framework).toBe("next");
+    expect(activePeerIds(manifest, "native").framework).toBe("expo");
+  });
+});

packages/registry/src/resolver.ts

@@ -45,7 +45,7 @@ export type ResolveResult =
  * always wins on tiebreak when no peers are required.
  */
 export function resolveAdapter(module: Module, context: ResolveContext): ResolveResult {
-  const activePeers = activePeerIds(context);
+  const activePeers = activePeerIdsForContext(context);
 
   // Check declared peers are satisfied (id present + on allow-list if specified).
   for (const category of PEER_CATEGORIES) {
@@ -87,20 +87,39 @@ export function isCompatible(module: Module, context: ResolveContext): boolean {
 }
 
 /**
- * Active peer ids — only `cardinality: "one"` categories can be peers, so we
- * iterate `PEER_CATEGORIES` and read the single installed/pending pick. When
- * `targetAppId` is set, the installed lookup is scoped to that app so e.g.
- * web's styling adapter peer-matches against web's framework, not native's.
+ * Active peer ids from the manifest alone — only `cardinality: "one"`
+ * categories can be peers, so we iterate `PEER_CATEGORIES` and read the
+ * single installed pick. When `targetAppId` is set, the lookup is scoped to
+ * that app so e.g. web's styling adapter peer-matches against web's
+ * framework, not native's.
+ *
+ * Exported so callers outside the resolver (the CLI runner and web
+ * synthesize, which both feed peers into the template render context) share
+ * exactly one implementation.
+ */
+export function activePeerIds(
+  manifest: StanzaManifest,
+  targetAppId?: string,
+): Partial<Record<CategoryId, string>> {
+  const out: Partial<Record<CategoryId, string>> = {};
+  for (const category of PEER_CATEGORIES) {
+    const installed = selectedOne(manifest, category, targetAppId)?.id;
+    if (installed) out[category] = installed;
+  }
+  return out;
+}
+
+/**
+ * Layer in-flight `pending` picks over the manifest's installed peers.
  * Pending picks aren't yet app-scoped — they belong to the same in-flight
  * resolution and only one app is being processed at a time.
  */
-function activePeerIds(context: ResolveContext): Partial<Record<CategoryId, string>> {
-  const out: Partial<Record<CategoryId, string>> = {};
+function activePeerIdsForContext(context: ResolveContext): Partial<Record<CategoryId, string>> {
+  const installed = activePeerIds(context.manifest, context.targetAppId);
+  const out: Partial<Record<CategoryId, string>> = { ...installed };
   for (const category of PEER_CATEGORIES) {
     const pending = context.pending[category]?.id;
-    const installed = selectedOne(context.manifest, category, context.targetAppId)?.id;
-    const chosen = pending ?? installed;
-    if (chosen) out[category] = chosen;
+    if (pending) out[category] = pending;
   }
   return out;
 }

packages/registry/src/synthesize.ts

@@ -146,7 +146,7 @@ export type SynthesizedTemplate = {
  */
 export function synthesizeTemplates(
   resolved: Partial<Record<CategoryId, SynthesizeEntry[]>>,
-  opts: { name: string; apps?: AppSpec[] },
+  opts: { name: string; apps?: AppSpec[]; peers?: Partial<Record<CategoryId, string>> },
 ): SynthesizedTemplate[] {
   const apps = opts.apps && opts.apps.length > 0 ? opts.apps : [defaultWebApp()];
   const out: SynthesizedTemplate[] = [];
@@ -170,6 +170,7 @@ export function synthesizeTemplates(
           projectName: opts.name,
           app,
           packageName,
+          peers: opts.peers,
         });
 
       for (const tpl of entry.adapter.templates ?? []) {

packages/registry/src/template.test.ts

@@ -40,18 +40,58 @@ describe("renderTemplate", () => {
     expect(renderTemplate("{{  project.name  }}", ctx)).toBe("acme");
   });
 
-  it("throws on a missing top-level key", () => {
-    expect(() => renderTemplate("{{missing}}", ctx)).toThrow(/missing or non-string key "missing"/);
+  it("renders missing keys as empty strings (non-strict Handlebars)", () => {
+    expect(renderTemplate("[{{missing}}]", ctx)).toBe("[]");
+    expect(renderTemplate("[{{packages.nope.name}}]", ctx)).toBe("[]");
   });
 
-  it("throws on a missing nested key", () => {
-    expect(() => renderTemplate("{{packages.nope.name}}", ctx)).toThrow(
-      /missing or non-string key "packages.nope.name"/,
-    );
+  it("does not HTML-escape values (noEscape=true)", () => {
+    // Without noEscape, the "/" in package names would become "/".
+    expect(renderTemplate("{{package.name}}", ctx)).toBe("@acme/auth");
   });
 
-  it("throws when a path resolves to an object instead of a string", () => {
-    expect(() => renderTemplate("{{project}}", ctx)).toThrow(/missing or non-string key "project"/);
+  describe("peers + conditionals", () => {
+    const withNext = buildRenderContext({
+      projectName: "acme",
+      app: webApp,
+      packageName: "",
+      peers: { framework: "next" },
+    });
+    const withTanstack = buildRenderContext({
+      projectName: "acme",
+      app: webApp,
+      packageName: "",
+      peers: { framework: "tanstack-start" },
+    });
+    const noFramework = buildRenderContext({
+      projectName: "acme",
+      app: webApp,
+      packageName: "",
+    });
+
+    it("renders an `if (eq)` block when the active peer matches", () => {
+      const tpl = '{{#if (eq peers.framework "next")}}NEXT{{/if}}';
+      expect(renderTemplate(tpl, withNext)).toBe("NEXT");
+      expect(renderTemplate(tpl, withTanstack)).toBe("");
+      expect(renderTemplate(tpl, noFramework)).toBe("");
+    });
+
+    it("matches hyphenated peer ids", () => {
+      const tpl = '{{#if (eq peers.framework "tanstack-start")}}TS{{/if}}';
+      expect(renderTemplate(tpl, withTanstack)).toBe("TS");
+      expect(renderTemplate(tpl, withNext)).toBe("");
+    });
+
+    it("renders an `unless` block when the active peer is absent", () => {
+      const tpl = "{{#unless peers.framework}}NONE{{/unless}}";
+      expect(renderTemplate(tpl, noFramework)).toBe("NONE");
+      expect(renderTemplate(tpl, withNext)).toBe("");
+    });
+
+    it("exposes the raw peer id under {{peers.<category>}}", () => {
+      expect(renderTemplate("[{{peers.framework}}]", withNext)).toBe("[next]");
+      expect(renderTemplate("[{{peers.framework}}]", noFramework)).toBe("[]");
+    });
   });
 });
 
@@ -66,6 +106,19 @@ describe("buildRenderContext", () => {
     expect(ctx.packages.auth?.name).toBe("@acme/auth");
     expect(ctx.packages.db?.name).toBe("@acme/db");
   });
+
+  it("materializes every PEER_CATEGORIES key under `peers` (undefined when unset)", () => {
+    const ctx = buildRenderContext({
+      projectName: "acme",
+      app: webApp,
+      packageName: "",
+      peers: { framework: "next" },
+    });
+    expect(ctx.peers.framework).toBe("next");
+    // styling is a PEER_CATEGORY but not set — the key exists, value is undefined.
+    expect("styling" in ctx.peers).toBe(true);
+    expect(ctx.peers.styling).toBeUndefined();
+  });
 });
 
 const drizzle: Module = defineModule({

packages/registry/src/template.ts

@@ -1,8 +1,10 @@
+import Handlebars from "handlebars";
+
 import type { AppSpec } from "./manifest";
-import { PACKAGE_DIRS } from "./module";
+import { type CategoryId, PACKAGE_DIRS, PEER_CATEGORIES } from "./module";
 
 /**
- * Mustache-style context consumed by {@link renderTemplate}. The shape is the
+ * Handlebars context consumed by {@link renderTemplate}. The shape is the
  * public contract template authors write against:
  *
  *   {{ project.name }}        — the manifest's `name` (a.k.a. the npm scope)
@@ -13,6 +15,10 @@ import { PACKAGE_DIRS } from "./module";
  *                               Empty string for categories whose `home.kind` isn't "package".
  *   {{ packages.<dir>.name }} — any other package by its dir, e.g. {{ packages.db.name }}
  *                               → "@my-app/db". One entry per `PACKAGE_DIRS` member.
+ *   {{ peers.<category> }}    — id of the active one-cardinality module in that
+ *                               category, or undefined. Useful with the `eq`
+ *                               helper for conditional blocks:
+ *                               {{#if (eq peers.framework "next")}}…{{/if}}
  *
  * `app.*` is rebound per target app on every render pass, so a module installed
  * into two apps renders correctly in each.
@@ -22,30 +28,29 @@ export type TemplateContext = {
   app: { id: string; dir: string; kind: string };
   package: { name: string };
   packages: Record<string, { name: string }>;
+  peers: Partial<Record<CategoryId, string>>;
 };
 
+// Module-singleton instance so registered helpers don't leak into other
+// Handlebars consumers (the global is shared otherwise).
+const hb = Handlebars.create();
+
+// String-equality helper for matching against a peer id, e.g.
+//   {{#if (eq peers.framework "next")}}…{{/if}}
+hb.registerHelper("eq", (a: unknown, b: unknown) => a === b);
+
 /**
- * Resolve `{{ a.b.c }}` references against a {@link TemplateContext}. Pure
- * regex + path walk — no helpers, no logic. Templates that need branching
- * should live as separate files and the codemod picks which one to render.
+ * Render a Handlebars template against a {@link TemplateContext}. Output is
+ * never HTML-escaped (`noEscape: true`) because templates emit code (JS/TS/
+ * JSON), not markup.
  *
- * Throws on missing keys so silent stub-outs can't ship to users. The CLI's
- * apply path and the web preview share this primitive, so a fresh `{{ ... }}`
- * with a typo fails the same way in both.
+ * Missing keys render as empty strings (Handlebars' default non-strict
+ * behavior). The CLI's apply path and the web preview share this primitive,
+ * so substitutions resolve identically in both.
  */
 export function renderTemplate(source: string, context: TemplateContext): string {
-  return source.replace(/\{\{\s*([\w.-]+)\s*\}\}/g, (_, key: string) => {
-    const value = key.split(".").reduce<unknown>((acc, part) => {
-      if (acc !== null && typeof acc === "object" && part in acc) {
-        return Reflect.get(acc, part);
-      }
-      return undefined;
-    }, context);
-    if (typeof value !== "string") {
-      throw new Error(`renderTemplate: missing or non-string key "${key}"`);
-    }
-    return value;
-  });
+  const template = hb.compile(source, { noEscape: true });
+  return template(context);
 }
 
 /**
@@ -57,20 +62,29 @@ export function renderTemplate(source: string, context: TemplateContext): string
  * Each (module, target-app) iteration in the runner builds a fresh context so
  * `app.*` points at the currently-applying app — that's how the same module's
  * templates land correctly when shipped into multiple apps.
+ *
+ * Every `PEER_CATEGORIES` key is materialized under `peers` (with `undefined`
+ * when no module is selected) so templates can safely reference any peer slot
+ * — that lets `{{peers.framework}}` resolve to `undefined` rather than walk
+ * off the end of a missing path.
  */
 export function buildRenderContext(opts: {
   projectName: string;
   app: AppSpec;
   packageName: string;
+  peers?: Partial<Record<CategoryId, string>>;
 }): TemplateContext {
   const packages: Record<string, { name: string }> = {};
   for (const dir of PACKAGE_DIRS) {
     packages[dir] = { name: `@${opts.projectName}/${dir}` };
   }
+  const peers: Partial<Record<CategoryId, string>> = {};
+  for (const cat of PEER_CATEGORIES) peers[cat] = opts.peers?.[cat];
   return {
     project: { name: opts.projectName },
     app: { id: opts.app.id, dir: opts.app.dir, kind: opts.app.kind },
     package: { name: opts.packageName },
     packages,
+    peers,
   };
 }

registry/modules/tooling-eslint-prettier/module.ts

@@ -1,4 +1,12 @@
-import { defineModule } from "@stanza/registry";
+import { defineModule, type TemplateRef } from "@stanza/registry";
+
+// Same templates regardless of which framework adapter wins. The eslint config
+// is a single Handlebars template that branches on `{{peers.framework}}`, so
+// pure-TS, Next, and TanStack Start all render from the same source file.
+const templates: TemplateRef[] = [
+  { src: "eslint.config.mjs", dest: "eslint.config.mjs", scope: "repo", template: true },
+  { src: "prettier.config.mjs", dest: "prettier.config.mjs", scope: "repo" },
+];
 
 export default defineModule({
   id: "eslint-prettier",
@@ -7,13 +15,14 @@ export default defineModule({
   description: "ESLint (flat config) for linting and Prettier for formatting.",
   version: "0.1.0",
   homepage: "https://eslint.org",
-  // ESLint config differs per framework, so dispatch on the framework pick.
-  peers: { framework: ["next", "tanstack-start"] },
+  // Framework-agnostic base; adapters layer on framework-specific plugins via
+  // Handlebars conditionals in the shared template — same shape as the
+  // tooling-biome / tooling-oxlint-oxfmt siblings, which also install without
+  // a framework peer.
   devDependencies: {
     eslint: "^9.39.0",
     "@eslint/js": "^9.39.0",
     "typescript-eslint": "^8.46.0",
-    "eslint-plugin-react-hooks": "^7.0.0",
     prettier: "^3.6.2",
     "eslint-config-prettier": "^10.1.8",
   },
@@ -25,20 +34,25 @@ export default defineModule({
     {
       key: "next",
       match: { framework: "next" },
-      devDependencies: { "@next/eslint-plugin-next": "^16.2.6" },
-      templates: [
-        { src: "eslint.config.next.mjs", dest: "eslint.config.mjs", scope: "repo" },
-        { src: "prettier.config.mjs", dest: "prettier.config.mjs", scope: "repo" },
-      ],
+      devDependencies: {
+        "@next/eslint-plugin-next": "^16.2.6",
+        "eslint-plugin-react-hooks": "^7.0.0",
+      },
+      templates,
     },
     {
       key: "tanstack-start",
       match: { framework: "tanstack-start" },
-      devDependencies: { "eslint-plugin-react": "^7.37.5" },
-      templates: [
-        { src: "eslint.config.tanstack.mjs", dest: "eslint.config.mjs", scope: "repo" },
-        { src: "prettier.config.mjs", dest: "prettier.config.mjs", scope: "repo" },
-      ],
+      devDependencies: {
+        "eslint-plugin-react": "^7.37.5",
+        "eslint-plugin-react-hooks": "^7.0.0",
+      },
+      templates,
+    },
+    {
+      key: "default",
+      match: {},
+      templates,
     },
   ],
 });

registry/modules/tooling-eslint-prettier/templates/eslint.config.mjs

@@ -0,0 +1,55 @@
+import js from "@eslint/js";
+import tseslint from "typescript-eslint";
+{{#if (eq peers.framework "next")}}
+import next from "@next/eslint-plugin-next";
+import reactHooks from "eslint-plugin-react-hooks";
+{{/if}}
+{{#if (eq peers.framework "tanstack-start")}}
+import react from "eslint-plugin-react";
+import reactHooks from "eslint-plugin-react-hooks";
+{{/if}}
+import prettier from "eslint-config-prettier";
+
+export default tseslint.config(
+  {
+    ignores: [
+      "**/node_modules/**",
+      "**/dist/**",
+{{#if (eq peers.framework "next")}}
+      "**/.next/**",
+      "**/next-env.d.ts",
+{{/if}}
+{{#if (eq peers.framework "tanstack-start")}}
+      "**/.output/**",
+      "**/.nitro/**",
+      "**/routeTree.gen.ts",
+{{/if}}
+    ],
+  },
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+{{#if (eq peers.framework "next")}}
+  {
+    plugins: {
+      "@next/next": next,
+      "react-hooks": reactHooks,
+    },
+    rules: {
+      ...next.configs.recommended.rules,
+      ...next.configs["core-web-vitals"].rules,
+      ...reactHooks.configs.recommended.rules,
+    },
+  },
+{{/if}}
+{{#if (eq peers.framework "tanstack-start")}}
+  {
+    plugins: { react, "react-hooks": reactHooks },
+    settings: { react: { version: "detect" } },
+    rules: {
+      ...reactHooks.configs.recommended.rules,
+      "react/react-in-jsx-scope": "off",
+    },
+  },
+{{/if}}
+  prettier,
+);

registry/modules/tooling-eslint-prettier/templates/eslint.config.next.mjs

@@ -1,24 +0,0 @@
-import js from "@eslint/js";
-import next from "@next/eslint-plugin-next";
-import reactHooks from "eslint-plugin-react-hooks";
-import tseslint from "typescript-eslint";
-import prettier from "eslint-config-prettier";
-
-export default tseslint.config(
-  { ignores: ["**/.next/**", "**/node_modules/**", "**/next-env.d.ts", "**/dist/**"] },
-  js.configs.recommended,
-  ...tseslint.configs.recommended,
-  {
-    plugins: {
-      "@next/next": next,
-      "react-hooks": reactHooks,
-    },
-    rules: {
-      ...next.configs.recommended.rules,
-      ...next.configs["core-web-vitals"].rules,
-      ...reactHooks.configs.recommended.rules,
-    },
-  },
-  // Disables stylistic rules that conflict with Prettier — keep last.
-  prettier,
-);

registry/modules/tooling-eslint-prettier/templates/eslint.config.tanstack.mjs

@@ -1,21 +0,0 @@
-import js from "@eslint/js";
-import react from "eslint-plugin-react";
-import reactHooks from "eslint-plugin-react-hooks";
-import tseslint from "typescript-eslint";
-import prettier from "eslint-config-prettier";
-
-export default tseslint.config(
-  { ignores: ["**/dist/**", "**/.output/**", "**/.nitro/**", "**/node_modules/**", "**/routeTree.gen.ts"] },
-  js.configs.recommended,
-  ...tseslint.configs.recommended,
-  {
-    plugins: { react, "react-hooks": reactHooks },
-    settings: { react: { version: "detect" } },
-    rules: {
-      ...reactHooks.configs.recommended.rules,
-      "react/react-in-jsx-scope": "off",
-    },
-  },
-  // Disables stylistic rules that conflict with Prettier — keep last.
-  prettier,
-);