# Nanostores MCP

> Debug and analyze Nanostores apps with AI: scan stores, monitor runtime events, and search docs.

- **Type:** MCP server
- **Install:** `agentstack add mcp-valyay-nanostores-mcp`
- **Verified:** Pending review
- **Seller:** [Valyay](https://agentstack.voostack.com/s/valyay)
- **Installs:** 0
- **Latest version:** 0.1.1
- **License:** MIT
- **Upstream author:** [Valyay](https://github.com/Valyay)
- **Source:** https://github.com/Valyay/nanostores-mcp

## Install

```sh
agentstack add mcp-valyay-nanostores-mcp
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Nano Stores MCP

**Model Context Protocol server for Nanostores** — analyze, debug and monitor
your nanostores in AI assistants like Claude Desktop.

- **📊 Static Analysis:** AST-based project scanning, dependency graphs, store inspection
- **🔥 Runtime Monitoring:** Live events from `@nanostores/logger`, performance metrics, activity tracking
- **📚 Documentation:** Search and browse Nanostores docs by topic or store kind
- **🎯 Zero Config:** Works out of the box — auto-detects project roots and nanostores docs
- **🌐 Framework-Agnostic:** Works with React, Vue, Svelte, Angular, Solid, Preact, Lit — any framework that uses Nanostores

```bash
npx nanostores-mcp
```

Ask your AI: _"Analyze my store architecture"_ or _"Which stores update most frequently?"_

---

 Made at Evil Martians, product consulting for developer tools.

---

## Table of Contents

- [Features](#features)
- [Requirements](#requirements)
- [Installation](#installation)
- [Configuration](#configuration)
- [Quick Start](#quick-start)
- [MCP Interface](#mcp-interface)
  - [Resources](#mcp-resources)
  - [Tools](#mcp-tools)
  - [Advanced Tool Arguments](#advanced-tool-arguments)
  - [Prompts](#mcp-prompts)
- [Runtime Monitoring](#runtime-monitoring)
  - [Reading Results](#reading-results)
  - [Privacy & Security](#privacy--security)
- [Example Queries](#example-queries)
- [Architecture](#architecture)
- [Limitations & Caveats](#limitations--caveats)
- [Development](#development)
- [Troubleshooting](#troubleshooting)

## Features

### 📊 Static Analysis (AST-based)

Understand your nanostores architecture without running your app:

- **Project scanning** — find all stores, subscribers, and import/export relationships
- **Dependency graph** — visualize how stores depend on each other (Mermaid diagrams)
- **Store inspection** — type (atom/map/computed/batched/persistentAtom/persistentMap/router), location, usage patterns, related files
- **Framework-aware subscriber detection** — recognizes `.subscribe()` / `.listen()` calls and component bindings across React, Vue, Svelte, and Angular
- **Vue SFC support** — parses both `` and `` blocks in `.vue` files (requires `@vue/compiler-sfc`)
- **Svelte support** — parses `` and instance `` blocks, auto-subscriptions (`$storeName` in templates), and filters out Svelte 5 runes (`$state`, `$derived`, `$effect`, etc.) so they are not mistaken for store references (requires `svelte`)
- **Angular DI support** — resolves `@nanostores/angular` `NanostoresService` constructor injections and detects `this.nanostores.useStore(...)` call patterns in TypeScript component files

### 🔥 Runtime Monitoring (Logger Integration)

Real-time insights into your running application:

- **Live event capture** — mount/unmount, value changes, action calls from `@nanostores/logger`
- **Performance analysis** — find noisy stores, high error rates, performance bottlenecks
- **Activity metrics** — change frequency, action success/failure rates, action duration
- **Combined analysis** — merge static structure with runtime behavior for deep debugging

### 📚 Documentation Search

Search and browse Nanostores documentation directly from your AI assistant:

- **Full-text search** — find guides, API references, and best practices by query
- **Store-kind lookup** — get docs relevant to a specific store type (atom, map, computed, etc.)
- **Auto-detection** — picks up docs from `nanostores` in your `node_modules` automatically

## Requirements

| Requirement | Version                 |
| ----------- | ----------------------- |
| Node.js     | `^20.0.0 \|\| >=22.0.0` |

**Required peer dependency** (for static analysis):

```bash
npm install nanostores
```

**Optional peer dependencies** — install only if you use the corresponding file format:

| Package              | When needed                            |
| -------------------- | -------------------------------------- |
| `@vue/compiler-sfc`  | Vue SFC (`.vue`) file scanning         |
| `svelte`             | Svelte (`.svelte`) file scanning       |
| `@nanostores/logger` | Runtime monitoring (`attachMcpLogger`) |

Without these optional packages the server still works — it silently skips unsupported file types.

## Installation

```bash
npm install -g nanostores-mcp
# or
pnpm add -g nanostores-mcp
```

Or run directly without installation:

```bash
npx nanostores-mcp
```

## Configuration

### Claude Desktop

Add to `~/Library/Application Support/Claude/claude_desktop_config.json` (macOS) or `%APPDATA%\Claude\claude_desktop_config.json` (Windows):

```json
{
	"mcpServers": {
		"nanostores": {
			"command": "npx",
			"args": ["-y", "nanostores-mcp"],
			"env": {
				"NANOSTORES_MCP_ROOT": "/path/to/your/project"
			}
		}
	}
}
```

### VS Code

Requires **GitHub Copilot** extension (VS Code 1.99+). Create `.vscode/mcp.json` in your project:

```json
{
	"servers": {
		"nanostores": {
			"type": "stdio",
			"command": "npx",
			"args": ["-y", "nanostores-mcp"]
		}
	}
}
```

Tools are available in Copilot's **Agent mode** (select "Agent" in the Copilot Chat dropdown).

### Cursor

Create `.cursor/mcp.json` in your project root (or `~/.cursor/mcp.json` for global):

```json
{
	"mcpServers": {
		"nanostores": {
			"command": "npx",
			"args": ["-y", "nanostores-mcp"]
		}
	}
}
```

### Zed

Add to your Zed `settings.json`:

```json
{
	"context_servers": {
		"nanostores": {
			"command": "npx",
			"args": ["-y", "nanostores-mcp"],
			"env": {
				"NANOSTORES_MCP_ROOT": "/path/to/your/project"
			}
		}
	}
}
```

The server appears in Zed's **Agent Panel** settings.

### Windsurf

Add to `~/.codeium/windsurf/mcp_config.json`:

```json
{
	"mcpServers": {
		"nanostores": {
			"command": "npx",
			"args": ["-y", "nanostores-mcp"],
			"env": {
				"NANOSTORES_MCP_ROOT": "/path/to/your/project"
			}
		}
	}
}
```

You can also open this file from the MCP icon in the Cascade panel → "Configure".

### Claude Code

Add via CLI:

```bash
claude mcp add --transport stdio nanostores -- npx -y nanostores-mcp
```

Or create `.mcp.json` in your project root (shared with the team):

```json
{
	"mcpServers": {
		"nanostores": {
			"command": "npx",
			"args": ["-y", "nanostores-mcp"],
			"env": {
				"NANOSTORES_MCP_ROOT": "/path/to/your/project"
			}
		}
	}
}
```

### Environment Variables

| Variable                        | Default     | Description                                                                     |
| ------------------------------- | ----------- | ------------------------------------------------------------------------------- |
| `NANOSTORES_MCP_ROOT`           | cwd         | Project root path                                                               |
| `NANOSTORES_MCP_ROOTS`          | —           | Platform-delimited roots (`:` on Unix, `;` on Windows) for multi-project setup  |
| `WORKSPACE_FOLDER`              | —           | Alias for `NANOSTORES_MCP_ROOT` — set automatically by VS Code and some editors |
| `WORKSPACE_FOLDER_PATHS`        | —           | Alias for `NANOSTORES_MCP_ROOTS` — set automatically by some editors            |
| `NANOSTORES_MCP_LOGGER_ENABLED` | `true`      | Set to `false` or `0` to disable runtime event collection and the logger bridge |
| `NANOSTORES_MCP_LOGGER_PORT`    | `3999`      | HTTP port for logger bridge                                                     |
| `NANOSTORES_MCP_LOGGER_HOST`    | `127.0.0.1` | Host to bind. Allowed values: `127.0.0.1`, `localhost`, `::1`                   |
| `NANOSTORES_DOCS_ROOT`          | auto-detect | Path to documentation directory                                                 |
| `NANOSTORES_DOCS_PATTERNS`      | `**/*.md`   | Comma-separated glob patterns for docs                                          |

### How the Project Root Is Resolved

The server picks workspace roots in priority order:

1. **Environment variables** (highest priority) — `NANOSTORES_MCP_ROOTS` / `NANOSTORES_MCP_ROOT` / `WORKSPACE_FOLDER_PATHS` / `WORKSPACE_FOLDER`
2. **Client roots** — roots reported by the MCP client via the `roots/list` capability (set automatically by some editors)
3. **Current working directory** — `process.cwd()` used as fallback when neither env nor client roots are configured

When a tool is called without an explicit `projectRoot` argument the server uses the **first configured root**. In a multi-root setup always pass `projectRoot` to avoid ambiguity.

## Quick Start

### 1. Static Analysis

Works out of the box — just point at your project and ask:

- _"Analyze my store architecture"_
- _"Explain how nanostores is used in this project"_
- _"Give me a summary of the $cart store"_
- _"My stores changed — re-scan the project"_ ← the AI will force a fresh scan

### 2. Documentation Search

Auto-detected from `nanostores` in your `node_modules`:

- _"How do I use computed stores?"_
- _"Show me the docs for persistentAtom"_

### 3. Runtime Monitoring (Optional)

Requires logger integration in your app. See [Runtime Monitoring](#runtime-monitoring) below.

- _"Which stores update most frequently?"_
- _"Show me recent activity for $user"_
- _"Give me an overall health report"_

### Verify Your Setup

Run these four tools in order to confirm everything is working:

```
nanostores_ping              → should return server status and logger bridge state
nanostores_scan_project      → should list your stores and subscribers
nanostores_docs_search       → should return documentation results (requires nanostores in node_modules)
nanostores_runtime_overview  → should return overview (or "no runtime data" if logger is disabled — that's fine)
```

If `nanostores_scan_project` returns zero stores, check that `NANOSTORES_MCP_ROOT` points to the correct project directory.

## MCP Interface

### MCP Resources

| Resource                      | Description                              |
| ----------------------------- | ---------------------------------------- |
| `nanostores://graph`          | Full dependency graph (text + Mermaid)   |
| `nanostores://store/{key}`    | Store details by name or id              |
| `nanostores://docs`           | Documentation index — all pages and tags |
| `nanostores://docs/page/{id}` | Full content of a documentation page     |

### MCP Tools

**Static Analysis**

| Tool                         | Description                                                       |
| ---------------------------- | ----------------------------------------------------------------- |
| `nanostores_scan_project`    | Scan project for all stores, subscribers, and dependencies        |
| `nanostores_store_summary`   | Detailed summary of a specific store                              |
| `nanostores_project_outline` | High-level overview: store kinds, top directories, hub stores     |
| `nanostores_store_subgraph`  | BFS-expanded dependency neighborhood of a store                   |
| `nanostores_store_impact`    | Downstream causal chain — what recomputes/re-renders if X changes |

**Runtime Monitoring**

| Tool                           | Description                                                        |
| ------------------------------ | ------------------------------------------------------------------ |
| `nanostores_runtime_overview`  | Overall health report with statistics for all stores               |
| `nanostores_store_activity`    | Activity timeline for a specific store (filterable by kind/action) |
| `nanostores_find_noisy_stores` | Identify stores with high change frequency or error rates          |
| `nanostores_runtime_coverage`  | Compare static graph with runtime events to find coverage gaps     |

**Documentation**

| Tool                     | Description                                                                                                                                  |
| ------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------- |
| `nanostores_docs_search` | Search docs by `query` (full-text), `storeKind` (atom, map, computed, persistentAtom, etc.), or both. Optional: `limit` (default 10), `tags` |

Use `nanostores://docs/page/{id}` resource to read the full content of pages returned by search.

**Utilities**

| Tool                     | Description                                  |
| ------------------------ | -------------------------------------------- |
| `nanostores_ping`        | Server health check and logger bridge status |
| `nanostores_clear_cache` | Clear project index cache to force rescan    |

### MCP Prompts

| Prompt                   | Parameters                | Description                                                                                                               |
| ------------------------ | ------------------------- | ------------------------------------------------------------------------------------------------------------------------- |
| `explain-project`        | `focus` _(optional)_      | AI-guided explanation of your project's store architecture. `focus` narrows to a feature/domain (e.g. `"cart"`, `"auth"`) |
| `explain-store`          | `store_name` _(required)_ | Deep dive into a specific store's implementation and usage                                                                |
| `debug-store`            | `store_name` _(required)_ | Comprehensive analysis combining static + runtime data                                                                    |
| `debug-project-activity` | —                         | Project-wide performance analysis and optimization                                                                        |
| `docs-how-to`            | `task` _(required)_       | Step-by-step guidance for a Nanostores task, backed by docs (e.g. `"How do I sync a map store to localStorage?"`)         |

### Advanced Tool Arguments

Most tools accept these optional arguments that significantly change their behavior:

| Argument      | Type                         | Used in                                                   | Description                                                                                                                                                                                    |
| ------------- | ---------------------------- | --------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `storeId`     | `string`                     | `store_summary`, `store_subgraph`, `store_impact`         | Exact store identifier — format: `store:src/stores.ts#$counterName`. Takes priority over `name` when both are provided.                                                                        |
| `name`        | `string`                     | `store_summary`, `store_subgraph`, `store_impact`         | Store name (e.g. `"$user"`). Used when `storeId` is not provided.                                                                                                                              |
| `radius`      | `number` (0–10, default `2`) | `nanostores_store_subgraph`                               | BFS hops around the store. `1` = direct deps only; `2` = deps of deps. **Warning:** on highly-connected hub stores (hub score > 5) radius ≥ 2 may return most of the project — start with `1`. |
| `projectRoot` | `string`                     | most tools                                                | Which project root to analyze in multi-root setups. Omit to use the first configured root. Always specify this in multi-root projects.                                                         |
| `windowMs`    | `number`                     | `store_activity`, `find_noisy_stores`, `runtime_overview` | Look-back window in milliseconds (e.g. `60000` = last 60 s). Filters events to that

…

## Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [Valyay](https://github.com/Valyay)
- **Source:** [Valyay/nanostores-mcp](https://github.com/Valyay/nanostores-mcp)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Versions

- **0.1.1** — security scan: pending review — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/mcp-valyay-nanostores-mcp
- Seller: https://agentstack.voostack.com/s/valyay
- Browse the marketplace: https://agentstack.voostack.com/browse

---
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