refactor(appkit): dedup agent folder-listing + make code-agent detection .ts-only

From the /simplify pass:
- Extract agentDirNames() so both loaders share one folder-selection policy
  (dir + symlink) instead of duplicating the subtle filter + comment.
- Code-agent source detection is .ts-only (resolveCodeAgentsDir source exts +
  hasCodeAgentSources), matching the build entry glob — an agent.tsx would
  otherwise load in dev but never be emitted for a prod bundle.

Signed-off-by: MarioCadenas <MarioCadenas@users.noreply.github.com>

Author: MarioCadenas

packages/appkit/src/core/agent/agent-dirs.ts

@@ -0,0 +1,14 @@
+import type { Dirent } from "node:fs";
+
+/**
+ * Agent-folder names from a directory listing, sorted. An agent lives in a
+ * subfolder, so directories count — and symlinks-to-directories too (a shared
+ * agent folder linked into the agents dir). Single-sourced so the markdown and
+ * code loaders keep the same folder-selection policy.
+ */
+export function agentDirNames(entries: Dirent[]): string[] {
+  return entries
+    .filter((e) => e.isDirectory() || e.isSymbolicLink())
+    .map((e) => e.name)
+    .sort();
+}

packages/appkit/src/core/agent/load-agents.ts

@@ -15,6 +15,7 @@ import type {
 } from "../../core/agent/types";
 import { isToolkitEntry } from "../../core/agent/types";
 import { createLogger } from "../../logging/logger";
+import { agentDirNames } from "./agent-dirs";
 
 const logger = createLogger("agents:loader");
 
@@ -206,12 +207,8 @@ export async function loadAgentsFromDir(
     );
   }
 
-  const agentIds = entries
-    // Symlinked agent folders count; a symlink to a file is filtered out below
-    // when reading agent.md (ENOTDIR).
-    .filter((e) => e.isDirectory() || e.isSymbolicLink())
-    .map((e) => e.name)
-    .sort();
+  // A symlink to a file is filtered out below when reading agent.md (ENOTDIR).
+  const agentIds = agentDirNames(entries);
 
   const defs: Record<string, AgentDefinition> = {};
   const subAgentRefs: Record<string, string[]> = {};

packages/appkit/src/core/agent/load-code-agents.ts

@@ -4,6 +4,7 @@ import path from "node:path";
 import { pathToFileURL } from "node:url";
 
 import { createLogger } from "../../logging/logger";
+import { agentDirNames } from "./agent-dirs";
 import { isCreatedAgent } from "./create-agent";
 import type { AgentDefinition } from "./types";
 
@@ -44,7 +45,9 @@ export function resolveCodeAgentsDir(opts: {
   const name = path.basename(sourceRel);
   const source: ResolvedCodeAgentsDir = {
     dir: path.resolve(opts.cwd, sourceRel),
-    extensions: [".ts", ".tsx"],
+    // `.ts` only: the build entry glob is `<dir>/*/agent.ts`, so an `agent.tsx`
+    // would load in dev but never be emitted for a prod bundle.
+    extensions: [".ts"],
   };
   const built: ResolvedCodeAgentsDir[] = CODE_AGENTS_BUILT_ROOTS.map(
     (root) => ({
@@ -130,12 +133,9 @@ export async function loadCodeAgentsFromDir(
     throw err;
   }
 
-  const folders = entries
-    // Include symlinked agent folders; findEntryFile's readdir follows the link
-    // and returns null for anything that isn't a real directory.
-    .filter((e) => e.isDirectory() || e.isSymbolicLink())
-    .map((e) => e.name)
-    .sort();
+  // findEntryFile's readdir follows a symlinked folder and returns null for
+  // anything that isn't a real directory.
+  const folders = agentDirNames(entries);
 
   const agents: Record<string, AgentDefinition> = {};
 

packages/appkit/src/plugins/agents/agents.ts

@@ -539,15 +539,13 @@ export class AgentsPlugin extends Plugin implements ToolProvider {
     return discovered;
   }
 
-  /** True when `dir` holds at least one `<id>/agent.{ts,tsx}` folder. */
+  /** True when `dir` holds at least one `<id>/agent.ts` folder. */
   private hasCodeAgentSources(dir: string): boolean {
     try {
       return readdirSync(dir, { withFileTypes: true }).some((e) => {
         if (!e.isDirectory() && !e.isSymbolicLink()) return false;
         try {
-          return readdirSync(path.join(dir, e.name)).some(
-            (f) => f === "agent.ts" || f === "agent.tsx",
-          );
+          return readdirSync(path.join(dir, e.name)).includes("agent.ts");
         } catch {
           return false;
         }

packages/appkit/src/plugins/agents/tests/load-code-agents.test.ts

@@ -11,7 +11,7 @@ import {
 const fixtureDir = (name: string) =>
   fileURLToPath(new URL(`./fixtures/${name}`, import.meta.url));
 
-const TS = { extensions: [".ts", ".tsx"] };
+const TS = { extensions: [".ts"] };
 
 describe("loadCodeAgentsFromDir", () => {
   it("returns an empty record when the directory does not exist", async () => {
@@ -91,7 +91,7 @@ describe("resolveCodeAgentsDir", () => {
     // No built output → falls back to the source `.ts` dir.
     expect(
       resolveCodeAgentsDir({ cwd, override: "my-agents", exists: () => false }),
-    ).toEqual({ dir: customSrc, extensions: [".ts", ".tsx"] });
+    ).toEqual({ dir: customSrc, extensions: [".ts"] });
   });
 
   it("stays built-first when dir is set to the default value explicitly", () => {
@@ -117,11 +117,11 @@ describe("resolveCodeAgentsDir", () => {
 
   it("uses server/agents (.ts) only when no built dir exists", () => {
     const r = resolveCodeAgentsDir({ cwd, exists: existsIn(source) });
-    expect(r).toEqual({ dir: source, extensions: [".ts", ".tsx"] });
+    expect(r).toEqual({ dir: source, extensions: [".ts"] });
   });
 
   it("targets server/agents when nothing exists (empty scan downstream)", () => {
     const r = resolveCodeAgentsDir({ cwd, exists: () => false });
-    expect(r).toEqual({ dir: source, extensions: [".ts", ".tsx"] });
+    expect(r).toEqual({ dir: source, extensions: [".ts"] });
   });
 });