feat(cli): add MCP server for AI agent integration (#112)

* feat(cli): add MCP server for AI agent integration

Expose the CLI as an MCP (Model Context Protocol) server so AI agents
(Claude Code, Cursor, VS Code, etc.) can scaffold and modify projects
programmatically via stdio transport.

7 tools: bfs_get_guidance, bfs_get_schema, bfs_check_compatibility,
bfs_plan_project, bfs_create_project, bfs_plan_addition, bfs_add_feature

3 resources: compatibility-rules, stack-options, getting-started

Usage: create-better-fullstack mcp
Register: claude mcp add --transport stdio better-fullstack -- npx create-better-fullstack mcp

* docs: add feature roadmap and competitive analysis

Detailed expansion plans for Rust, Go, Python, TypeScript ecosystems,
new categories (GraphQL, i18n, rate limiting, desktop), platform features
(MCP server, add command, cross-ecosystem stacks), and competitive
analysis vs better-t-stack.

* fix(templates): Kysely empty Database interface and Drizzle missing NextAuth export

Kysely: when auth != better-auth, the Database interface was empty,
making the entire DB layer non-functional. Now generates an ExampleTable
as a starter schema.

Drizzle: barrel file only exported auth schema for better-auth but not
NextAuth, which also generates Drizzle schema files. Added NextAuth to
the conditional export.

* fix(cli): propagate addon setup warnings instead of silent failures

setupAddons() now returns a warnings array. addHandler() includes
warnings in AddResult so callers (including MCP) know when MCP/Skills
addon setup failed. Previously returned success: true with no indication
of failure.

* fix(templates): trailing newlines, tab-to-space in payments, prompt text

- Add trailing newlines to 52 .hbs template files (POSIX compliance)
- Convert tabs to 2-space indent in 4 payment TypeScript templates
- Change "Choose web" prompt to "Select web framework"
- Add codebase issues tracking doc

* fix(mcp): address code review issues from PR #112

- Prevent path traversal in bfs_create_project by calling sanitizePath
  and rejecting '..' path components
- Fix mcp --help hang by only intercepting bare 'mcp' subcommand
- Run setupAddons after writing files in bfs_create_project
- Add missing types field to ./mcp package.json export
- Fix misleading self-* notation in COMPATIBILITY_RULES_MD
- Fix summarizeTree type mismatch with VirtualFileTree

* fix: update template snapshots to match current templates

* ci: retrigger CI

* fix(mcp): unify plan/create config defaults via shared buildProjectConfig

bfs_plan_project used createVirtual which had different defaults (api=trpc,
uiLibrary=shadcn-ui, testing=vitest, etc.) than bfs_create_project (all
"none"). This caused plan previews to show more files than create would
actually generate.

Extract buildProjectConfig() as single source of truth for both tools,
and share the Zod schema via planCreateSchema.

Author: Marve10s

apps/cli/package.json

@@ -85,6 +85,10 @@
     "./virtual": {
       "types": "./dist/virtual.d.mts",
       "import": "./dist/virtual.mjs"
+    },
+    "./mcp": {
+      "types": "./dist/mcp-entry.d.mts",
+      "import": "./dist/mcp-entry.mjs"
     }
   },
   "publishConfig": {
@@ -123,6 +127,7 @@
     "oxfmt": "^0.19.0",
     "picocolors": "^1.1.1",
     "tinyglobby": "^0.2.15",
+    "@modelcontextprotocol/sdk": "^1.12.1",
     "trpc-cli": "^0.12.1",
     "ts-morph": "^27.0.2",
     "yaml": "^2.8.3",

apps/cli/src/cli.ts

@@ -1,3 +1,6 @@
-import { createBtsCli } from "./index";
-
-createBtsCli().run();
+const firstArg = process.argv[2];
+if (firstArg === "mcp" && process.argv.length === 3) {
+  import("./mcp.js").then((m) => m.startMcpServer());
+} else {
+  import("./index.js").then((m) => m.createBtsCli().run());
+}

apps/cli/src/helpers/addons/addons-setup.ts

@@ -15,7 +15,8 @@ import { setupTui } from "./tui-setup";
 import { setupUltracite } from "./ultracite-setup";
 import { setupWxt } from "./wxt-setup";
 
-export async function setupAddons(config: ProjectConfig) {
+export async function setupAddons(config: ProjectConfig): Promise<string[]> {
+  const warnings: string[] = [];
   const { addons, frontend, projectDir } = config;
   const hasReactWebFrontend =
     frontend.includes("react-router") ||
@@ -95,12 +96,22 @@ export async function setupAddons(config: ProjectConfig) {
   }
 
   if (addons.includes("mcp")) {
-    await setupMcp(config);
+    try {
+      await setupMcp(config);
+    } catch (error) {
+      warnings.push(`MCP setup failed: ${error instanceof Error ? error.message : String(error)}`);
+    }
   }
 
   if (addons.includes("skills")) {
-    await setupSkills(config);
+    try {
+      await setupSkills(config);
+    } catch (error) {
+      warnings.push(`Skills setup failed: ${error instanceof Error ? error.message : String(error)}`);
+    }
   }
+
+  return warnings;
 }
 
 export async function setupBiome(projectDir: string) {

apps/cli/src/helpers/core/add-handler.ts

@@ -31,6 +31,7 @@ export interface AddResult {
   addedAddons: Addons[];
   projectDir: string;
   error?: string;
+  setupWarnings?: string[];
 }
 
 export async function addHandler(
@@ -169,7 +170,7 @@ async function addHandlerInternal(input: AddInput): Promise<AddResult> {
 
   await writeTreeToFilesystem(tree, projectDir);
 
-  await setupAddons(config);
+  const setupWarnings = await setupAddons(config);
   await applyDependencyVersionChannel(projectDir, config.versionChannel);
 
   const updatedAddons = [...new Set([...existingAddons, ...addonsToAdd])];
@@ -197,6 +198,9 @@ async function addHandlerInternal(input: AddInput): Promise<AddResult> {
 
   if (!isSilent()) {
     log.success(pc.green(`Successfully added: ${addonsToAdd.join(", ")}`));
+    for (const warning of setupWarnings) {
+      log.warn(pc.yellow(warning));
+    }
     if (!input.install) {
       const installCmd =
         config.packageManager === "npm" ? "npm install" : `${config.packageManager} install`;
@@ -209,6 +213,7 @@ async function addHandlerInternal(input: AddInput): Promise<AddResult> {
     success: true,
     addedAddons: addonsToAdd,
     projectDir,
+    setupWarnings: setupWarnings.length > 0 ? setupWarnings : undefined,
   };
 }
 

apps/cli/src/index.ts

@@ -364,6 +364,12 @@ export const router = os.router({
         ecosystem: input.ecosystem,
       });
     }),
+  mcp: os
+    .meta({ description: "Start MCP server for AI agent integration (stdio transport)" })
+    .handler(async () => {
+      log.message("MCP server is started via the 'mcp' subcommand intercepted in cli.ts.");
+      log.message("Run: create-better-fullstack mcp");
+    }),
 });
 
 const caller = createRouterClient(router, { context: {} });

apps/cli/src/mcp-entry.ts

@@ -0,0 +1,3 @@
+import { startMcpServer } from "./mcp.js";
+
+startMcpServer();