feat: Web POC with ZenStack v3, Turso, and MCP Auto-Sync

[beshkenadze]

Summary

This PR introduces a web-based Kanban board POC built with Next.js 14, ZenStack v3 ORM, and Turso database, along with MCP server auto-sync capabilities for seamless AI agent integration.

Features

Web POC (apps/web-poc)

• Next.js 14 with App Router and React Server Components
• ZenStack v3 ORM with automatic CRUD API generation
• Turso database with embedded replicas for offline-first sync
• Drag-and-drop Kanban board using @hello-pangea/dnd
• shadcn/ui components with Tailwind CSS v4
• Cloudflare Workers deployment ready

MCP Auto-Sync (packages/cli)

• Automatic sync triggers after all mutating MCP operations
• Background sync using kaban turso-sync command
• 17 wrapped handlers: add, move, update, delete, archive, etc.
• Non-blocking - sync happens asynchronously

Turso Integration

• Manual sync command: kaban turso-sync
• Config schema extensions: driver, syncUrl, authToken, syncInterval
• Cloudflare serverless driver support

Changes

New Files

• apps/web-poc/ - Complete Next.js web application
• packages/cli/src/lib/mcp-auto-sync.ts - Auto-sync middleware
• packages/cli/src/commands/turso-sync.ts - Manual sync command
• docs/SYNC_ARCHITECTURE.md - Architecture documentation

Modified Files

• packages/core/src/schemas.ts - Add Turso config fields
• packages/core/src/db/types.ts - Add syncUrl/syncInterval to DbConfig
• packages/cli/src/commands/mcp.ts - Integrate auto-sync triggers
• packages/cli/src/index.ts - Export new commands

Deployment

Web POC deployed to: https://kaban-web-poc.personal-261.workers.dev

Testing

• All existing tests pass: 387 pass, 0 fail
• Build successful for all packages
• TypeScript compilation clean

Architecture

┌──────────────┐      ┌──────────────┐      ┌──────────────┐
│  AI Agent    │──────│  MCP Server  │──────│  Local DB    │
│  (Claude)    │      │  (auto-sync) │      │  (SQLite)    │
└──────────────┘      └──────────────┘      └──────┬───────┘
                                                   │ sync
                                            ┌──────▼───────┐
                                            │  Turso Cloud │
                                            └──────────────┘
                                                   │
                                            ┌──────▼───────┐
                                            │   Web UI     │
                                            └──────────────┘

Commits

1. 4785116 - feat(core): add Turso sync configuration to schemas and types
2. 66e475d - feat(cli): integrate auto-sync triggers into MCP server
3. 1e9bfd4 - feat(web-poc): add Cloudflare Turso client configuration
4. 703108e - docs: add Turso sync architecture documentation
5. 0448b22 - chore(web-poc): update dependencies for ZenStack and Turso
6. af0abd7 - fix(web-poc): fix Cloudflare deployment configuration

[Copilot]

Pull request overview

This PR introduces a web-based Kanban board proof-of-concept (POC) along with Turso database sync capabilities for the existing CLI/TUI Kaban board application. The implementation adds auto-sync functionality to the MCP server and creates a Next.js 14 web application intended to demonstrate real-time synchronization between CLI and web interfaces.

Changes:

• Added Turso database configuration options (driver, syncUrl, authToken, syncInterval) to core schemas
• Implemented MCP auto-sync middleware that triggers background Turso sync after mutating operations
• Created new turso-sync command for manual and automatic database synchronization
• Built a Next.js 14 web POC with ZenStack v3 ORM, drag-and-drop Kanban board, and Cloudflare Workers deployment configuration

Reviewed changes

Copilot reviewed 30 out of 32 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
packages/core/src/schemas.ts	Added Turso-specific configuration fields to ConfigSchema
packages/core/src/db/types.ts	Extended DbConfig interface with syncUrl and syncInterval
packages/cli/src/lib/mcp-auto-sync.ts	Implemented auto-sync wrapper for MCP handlers
packages/cli/src/commands/turso-sync.ts	Created manual Turso sync command with watch mode
packages/cli/src/commands/mcp.ts	Refactored MCP handlers to use auto-sync wrappers
packages/cli/src/index.ts	Registered turso-sync command
apps/web-poc/	Complete Next.js application with Kanban UI, ZenStack schema, and Cloudflare configuration
docs/SYNC_ARCHITECTURE.md	Added architecture documentation for Turso sync (in Russian)

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[Copilot]

Database connection resource leak: The db connection created by createContext on line 542 is never closed. Each MCP request (except kaban_init) creates a new database connection that remains open, leading to potential resource exhaustion. The database connection should be closed after the request is processed, either with a try-finally block or by ensuring db.$close() is called.

[Copilot]

Database connection resource leak in init handler: The database connection created on line 528 is never closed. After initializing the schema and board, the connection should be closed with db.$close() to prevent resource leaks.

[Copilot]

Race condition in syncInProgress flag: The syncInProgress flag is set to true synchronously but only reset asynchronously in the callback. If syncInBackground() is called multiple times in quick succession before exec() completes, the flag may not prevent concurrent syncs as intended. Additionally, if the exec() call throws before registering the callback (line 40-52), the catch block on line 55 resets the flag, but there's a window where the flag is true but no callback is registered to reset it.

Suggested change

	try {
	const { exec } = await import("node:child_process");
	exec(
	`kaban turso-sync`,
	{ env: { ...process.env, KABAN_AUTO_SYNC: "1" } },
	(error) => {
	if (error) {
	console.error("[AutoSync] Failed:", error.message);
	} else {
	console.log("[AutoSync] Success");
	}
	this.syncInProgress = false;
	}
	);
	} catch (error) {
	console.error("[AutoSync] Error:", error);
	// Fire-and-forget; internal helper will always reset the flag.
	void this.runSyncProcess();
	}
	private async runSyncProcess(): Promise<void> {
	try {
	const { exec } = await import("node:child_process");
	await new Promise<void>((resolve) => {
	exec(
	`kaban turso-sync`,
	{ env: { ...process.env, KABAN_AUTO_SYNC: "1" } },
	(error) => {
	if (error) {
	console.error("[AutoSync] Failed:", error.message);
	} else {
	console.log("[AutoSync] Success");
	}
	resolve();
	}
	);
	});
	} catch (error) {
	console.error("[AutoSync] Error:", error);
	} finally {

[Copilot]

Inconsistent import style mixing require and import: This function uses CommonJS require() for imports while the rest of the file uses ES6 import statements. For consistency and better TypeScript support, use ES6 imports at the top of the file instead of dynamic require() calls.

[Copilot]

Unused imports: The GripVertical and CardHeader imports are not used anywhere in this component. Remove them to keep the imports clean.

Suggested change

	import { Plus, MoreHorizontal, Calendar, Trash2, GripVertical } from "lucide-react";
	import { Button } from "@/components/ui/button";
	import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
	import { Plus, MoreHorizontal, Calendar, Trash2 } from "lucide-react";
	import { Button } from "@/components/ui/button";
	import { Card, CardContent, CardTitle } from "@/components/ui/card";

[Copilot]

Unused variable: The __dirname variable is defined but never used in this configuration file. Consider removing it to clean up the code.

Suggested change

	import { dirname, join } from "path";
	import { fileURLToPath } from "url";
	const __dirname = dirname(fileURLToPath(import.meta.url));

[Copilot]

Missing test coverage for turso-sync command: The new turso-sync command lacks test coverage. Since the repository uses comprehensive testing, this new command should have tests to verify the sync functionality, error handling, watch mode, and interval parsing.

[Copilot]

Web POC not integrated with database: The Kanban board page uses local useState instead of connecting to the database. The db.ts and db-cloudflare.ts files are created but never imported or used in the application. For this POC to demonstrate actual Turso sync capabilities as described in the PR, it should fetch and update tasks from the database rather than using hardcoded INITIAL_TASKS.

[Copilot]

Unused configuration field: The syncInterval field is defined in ConfigSchema and DbConfig but is never actually used in the codebase. The turso-sync command uses its own --interval option instead of reading from config.syncInterval. Either implement support for reading this from config or remove it from the schema to avoid confusion.

[Copilot]

Unused import join.

Suggested change

	import { dirname, join } from "path";
	import { dirname } from "path";

[Copilot]

Pull request overview

Copilot reviewed 33 out of 35 changed files in this pull request and generated 10 comments.

---

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[Copilot]

A command named kaban sync already exists (defined in packages/cli/src/commands/sync.ts) for syncing TodoWrite input to the Kaban board. Adding kaban turso-sync is correct to avoid this conflict, but the documentation in docs/SYNC_ARCHITECTURE.md incorrectly refers to the Turso sync command as kaban sync instead of kaban turso-sync. This will cause confusion for users trying to follow the documentation.

[Copilot]

The web POC application uses hardcoded mock data (INITIAL_TASKS defined at line 42) and has no actual database integration, despite the PR description claiming "ZenStack v3 ORM with automatic CRUD API generation" and "Turso database with embedded replicas." While lib/db.ts and lib/db-cloudflare.ts configure database clients, they are never imported or used in the application. This is a significant discrepancy between the PR description and the actual implementation - the web POC is currently just a static UI mockup.

[Copilot]

This hardcoded board ID in the DEFAULT_CONFIG is not actually used by the BoardService.initializeBoard method, which always generates a new ULID on line 12 of packages/core/src/services/board.ts. This makes the board.id field in the config misleading, as it suggests the board ID can be predefined when it actually gets overwritten during initialization.

[Copilot]

The database connection created at line 543 and assigned to the db variable is never closed, causing a resource leak. While the handlers are wrapped and the db is used within the request scope, the connection remains open for the entire lifetime of the MCP server. This is particularly problematic for long-running MCP servers. Consider closing the database connection after each request is handled, or implement connection pooling.

[Copilot]

The setInterval at line 58 is never cleared, preventing graceful shutdown. If the command is terminated with Ctrl+C, the interval will continue running until the process is forcefully killed. Consider storing the interval ID and adding process signal handlers to clear it on SIGINT/SIGTERM.

Suggested change

	setInterval(performSync, interval);
	const syncInterval = setInterval(performSync, interval);
	const shutdown = (signal: NodeJS.Signals) => {
	console.log(`\nReceived ${signal}. Stopping Turso sync...`);
	clearInterval(syncInterval);
	process.exit(0);
	};
	process.on("SIGINT", shutdown);
	process.on("SIGTERM", shutdown);

[Copilot]

The kaban turso-sync command hardcoded at line 42 may not be available in the PATH if the CLI is run from a development environment or installed in a custom location. Consider using process.execPath and resolving the command relative to the current binary location, similar to how packages/cli/src/commands/tui.ts handles finding binaries.

[Copilot]

The syncInProgress flag is set to true at line 37 but only set back to false inside the callback at line 50. If the exec call fails before the callback is invoked (e.g., if exec itself throws), the flag will remain true forever, preventing all future sync attempts. Consider wrapping the exec call in a try-catch and resetting the flag in a finally block.

[Copilot]

The database URL is accessed using the non-null assertion operator (!) at line 10, but there's no runtime validation that the environment variable is actually set. If TURSO_DATABASE_URL is undefined, this will result in passing undefined to the ZenStackClient, which will likely cause a runtime error. Consider adding explicit validation with a clear error message before creating the client.

Suggested change

	export const db = new ZenStackClient(schema, {
	adapter: 'libsql',
	url: process.env.TURSO_DATABASE_URL!,
	const databaseUrl = process.env.TURSO_DATABASE_URL;
	if (!databaseUrl) {
	throw new Error('Environment variable TURSO_DATABASE_URL is required but was not provided.');
	}
	export const db = new ZenStackClient(schema, {
	adapter: 'libsql',
	url: databaseUrl,

[Copilot]

The documentation references a kaban sync command at multiple locations (lines 55-57, 135, 145, 211, 233), but the actual implementation is named kaban turso-sync (as seen in packages/cli/src/commands/turso-sync.ts and packages/cli/src/index.ts line 51). This discrepancy between documentation and implementation will confuse users. The command should either be renamed to match the documentation or the documentation should be updated to reflect the actual command name.

[Copilot]

The sync() method is called on db.$client assuming it has this method, but this method only exists on libsql embedded replica clients, not on all libsql clients. The code checks for its existence (line 36), but when creating the database at line 29-33, there's no guarantee that an embedded replica was created. The syncUrl parameter is passed to createDb, but without checking the libsql client documentation, it's unclear if this is sufficient to enable embedded replica mode with sync support.

[Copilot]

Pull request overview

Copilot reviewed 36 out of 38 changed files in this pull request and generated 17 comments.

---

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[Copilot]

The executeQuery helper function creates a new database connection on every query execution but never closes it. This will lead to connection leaks and resource exhaustion. Either add connection cleanup (close/dispose) or reuse connections appropriately. Consider returning both the connection and result so the caller can close it, or implement proper connection pooling.

Suggested change

	// Helper to execute queries
	export async function executeQuery(query: string, params: unknown[] = []) {
	const conn = createCloudflareDB();
	// Lazily initialized, cached database connection for reuse
	let cachedCloudflareDB: ReturnType<typeof connect> | null = null;
	export function getCloudflareDB() {
	if (!cachedCloudflareDB) {
	cachedCloudflareDB = createCloudflareDB();
	}
	return cachedCloudflareDB;
	}
	// Helper to execute queries
	export async function executeQuery(query: string, params: unknown[] = []) {
	const conn = getCloudflareDB();

[Copilot]

SQL injection vulnerability: The placeholders variable is concatenated directly into the SQL string without proper parameterization. While columnIds comes from the database, constructing SQL with string interpolation for IN clauses is dangerous. Use proper parameterized queries. libsql/Turso should support binding arrays for IN clauses, or construct the query differently to avoid this pattern.

[Copilot]

The server actions (getBoardData, moveTask, addTask, archiveTask) lack input validation. For example, boardId, taskId, newColumnId, and other user-provided inputs are passed directly to SQL queries without validation. While parameterized queries prevent SQL injection, there should still be validation for input format (e.g., ULID format), length constraints, and business logic constraints to prevent invalid data from being processed.

[Copilot]

The onDragEnd handler updates the UI optimistically (line 77-92) but doesn't handle failures from moveTask. If the server action fails, the UI will show the task in the new column, but the database will have it in the old column, causing data inconsistency. Add error handling to revert the optimistic update if moveTask fails.

[Copilot]

The API route creates a new database client on every request but never closes it (lines 12-16). This will cause connection leaks. In a serverless environment like Cloudflare Workers, each request should properly clean up its resources. Add client.close() in a finally block or use proper connection management.

[Copilot]

The db-cloudflare.ts file and @tursodatabase/serverless dependency are not used anywhere in the application. The codebase only uses @libsql/client through lib/db.ts. Either remove the unused db-cloudflare.ts file and @tursodatabase/serverless dependency, or document why they're kept for future use.

[Copilot]

The performSync function creates a new database connection on every sync but doesn't handle connection pooling or reuse. In watch mode, this means creating and destroying a database connection every 30 seconds, which is inefficient. Consider creating the database connection once outside performSync and reusing it, or ensure proper connection management.

[Copilot]

The datasource url contains a hardcoded absolute path to a specific user's filesystem ('/Users/akira/Projects/My/KabanProject/.kaban/board.db'). This will not work for other developers or in production environments. This should use an environment variable like 'env("DATABASE_URL")' or be changed to a relative path.

Suggested change

	url = "file:/Users/akira/Projects/My/KabanProject/.kaban/board.db"
	url = env("DATABASE_URL")

[Copilot]

The sync() call on line 19 may fail or not be supported depending on the client configuration. If syncUrl is not provided, client.sync() might throw an error or be undefined. Add proper error handling or check if sync is available before calling it, similar to how it's done in turso-sync.ts (line 35-41).

Suggested change

	// Sync with remote before reading
	await client.sync();
	// Sync with remote before reading, if supported/configured
	if (process.env.TURSO_SYNC_URL && typeof (client as any).sync === 'function') {
	try {
	await client.sync();
	} catch (syncError) {
	console.warn('Turso sync failed, continuing with local replica:', syncError);
	}
	}

[Copilot]

The ZenStack schema uses @@Allow('all', true) for all models, which allows unrestricted access to all operations on all data. This completely bypasses ZenStack's access control features and poses a serious security risk. Even for a POC, this should implement basic access control rules or at least document that this is intentionally disabled for development purposes only.