How to add an MCP server to Claude Desktop (2026 step-by-step)

How Plugsky MCP works in practice

Everything in this guide runs on Plugsky’s live MCP endpoint (https://plugsky.com/mcp) or the npm bridge (npx -y @plugsky/mcp). A client request flows: JSON-RPC over Streamable-HTTP → auth (API key or OAuth 2.1 + Dynamic Client Registration with fine-grained scopes) → tool router → the service you asked for. Model calls run behind a 7-tier provider failover chain; browsing renders with headless Chromium; transcripts come from real captions and Groq Whisper; images generate on FLUX; code runs in a sandbox with no network; memory persists in your account (Postgres-backed); and every tool call is metered per user on your dashboard.

Relevant live tools for this article: plugsky_chat + the npx stdio bridge (Claude Desktop is the reference client).

How to add an MCP server to Claude Desktop (2026 step-by-step)

Direct answer

To add an MCP server to Claude Desktop in 2026: open Claude → Settings → Developer → Edit Config. This opens claude_desktop_config.json. Add your server under mcpServers with either a command (for stdio) or a url (for remote Streamable-HTTP). Save the file, fully quit Claude, and reopen. Your tools will appear in the paper-clip icon inside the chat input. Total time: under 60 seconds.

Key facts

Config file (macOS)	~/Library/Application Support/Claude/claude_desktop_config.json
Config file (Windows)	%APPDATA%\Claude\claude_desktop_config.json
Config file (Linux)	~/.config/Claude/claude_desktop_config.json
Top-level key	mcpServers
Transport support	stdio (local command), Streamable-HTTP (url)
Auth support	OAuth 2.1, Bearer, stdio env vars
MCP primitives supported	Tools, Prompts, Resources, Sampling
Reload behavior	Full quit + reopen required
Discoverability UI	Paper-clip icon → attach resource / trigger prompt
Free tier	Yes — all MCP features on Claude Free

TL;DR

• Claude Desktop is the reference MCP client — everything the spec supports, Claude supports.
• Config lives in a single JSON file under your OS's app-support directory.
• Add either a local command (like npx -y @plugsky/mcp) or a remote url (like https://plugsky.com/mcp).
• Fully quit and reopen Claude for the config to reload — a window refresh is not enough.
• Prompts appear as slash-commands; Resources appear in the paper-clip attach menu; Tools are auto-invoked mid-chat.

How it works

Step-by-step: add a remote MCP server (recommended)

Remote MCPs are hosted for you — no npm, no Python, no dependencies. Plugsky's https://plugsky.com/mcp is a good example.

1. Open Claude Desktop → Settings (Cmd/Ctrl+,) → Developer tab.
2. Click Edit Config. Your OS opens claude_desktop_config.json in the default editor.
3. Add this block:

```json

{

"mcpServers": {

"plugsky": {

"url": "https://plugsky.com/mcp",

"headers": {

"Authorization": "Bearer sk-live-YOUR_KEY_HERE"

}

}

}

}

```

1. Save the file.
2. Fully quit Claude Desktop (Cmd+Q / File → Quit — not just close the window).
3. Reopen Claude. You should see a small hammer icon in the chat input showing available tools.
4. Ask "Which Plugsky model is cheapest for Arabic summarization?" Claude will call plugsky_models and stream the answer.

Step-by-step: add a local MCP server (stdio)

Local MCPs run as a subprocess. Useful when you want filesystem access, or when a server is npm/pip-distributed.

1. Install prerequisites: Node.js 20+ (for npx) or Python 3.11+ (for uvx or pipx).
2. Open claude_desktop_config.json (same path as above).
3. Add this block for Plugsky's local variant:

```json

{

"mcpServers": {

"plugsky-local": {

"command": "npx",

"args": ["-y", "@plugsky/mcp"],

"env": {

"PLUGSKY_API_KEY": "sk-live-YOUR_KEY_HERE"

}

}

}

}

```

1. Save, quit Claude, reopen.
2. First launch takes ~10 seconds because npx downloads the package. Subsequent launches are instant.

Combining multiple MCP servers

You can register as many servers as you like. Claude merges their tool lists.

{
  "mcpServers": {
    "plugsky": { "url": "https://plugsky.com/mcp", "headers": {"Authorization":"Bearer sk-live-..."} },
    "filesystem": { "command": "npx", "args": ["-y","@modelcontextprotocol/server-filesystem","/Users/me/projects"] },
    "github": { "command": "npx", "args": ["-y","@modelcontextprotocol/server-github"], "env": {"GITHUB_PERSONAL_ACCESS_TOKEN":"ghp_..."} }
  }
}

Keep the total under ~10 servers so tools/list stays fast on startup.

What Claude gives you that other clients don't

Claude Desktop is Anthropic's reference implementation, so it lights up every MCP feature the moment the spec ships:

• Sampling — many MCPs use Claude's own context window to summarize before returning results (saves your tokens).
• Elicitation — mid-tool user prompts appear as clean modals, not chat noise.
• Roots — filesystem servers only see the folders you allowed.
• Prompts as slash-commands — a well-written server adds /plugsky:pick-cheapest, /plugsky:draft-arabic to Claude's slash menu.
• Resources in the paper-clip menu — RAG collections show up as attachable context, not just query targets.

OAuth vs Bearer — which to use in Claude?

OAuth 2.1 is the future. It generates per-user, per-scope tokens automatically and rotates them. Use OAuth when the server advertises it (Claude auto-detects via .well-known/oauth-protected-resource).

Bearer is faster to get running today. Paste the key once, done. The tradeoff: screenshots and shared configs can leak the key, and revocation is manual. Use Bearer for personal setups; require OAuth for team deployments.

Common errors and fixes

Tools icon doesn't appear	Config JSON is invalid	Run jq . claude_desktop_config.json — if it fails, fix the JSON
"Failed to spawn command"	npx / node / python not in PATH	Use absolute path in command (e.g. /usr/local/bin/npx)
Server appears but no tools	Auth failed silently	Check server logs; verify Bearer scope includes tool execution
Slash commands missing	Server didn't declare Prompts capability	Ask maintainer to add Prompts primitive
Reload doesn't pick up changes	Window closed but process kept running	Cmd+Q or killall Claude before reopening
Streamable-HTTP times out	Network / server region	Try nearest Plugsky region: eu.plugsky.com/mcp, ksa.plugsky.com/mcp

Comparison — Claude Desktop MCP vs Claude Code vs Claude.ai (web)

MCP support	Full	Full (+ CLI-native)	Via Connectors (limited)
Config location	claude_desktop_config.json	.claude/mcp.json in repo	Web UI
Best for	Everyday chat + agents	Coding, terminal workflows	Casual browser use
Local stdio	✅	✅	❌ (remote only)
Roots	✅	✅	⚠️

FAQ

Q: Where is the Claude Desktop MCP config file?

A: macOS: ~/Library/Application Support/Claude/claude_desktop_config.json. Windows: %APPDATA%\Claude\claude_desktop_config.json. Linux: ~/.config/Claude/claude_desktop_config.json.

Q: Do I need Claude Pro to use MCP?

A: No. MCP is free on all Claude Desktop tiers, including Free. You only pay for Claude's inference (which is metered by conversation, not by MCP calls).

Q: Why don't my changes to the config take effect?

A: You closed the window but Claude is still running in the background. Fully quit with Cmd+Q (macOS) or File → Exit (Windows), then reopen.

Q: Can I use Plugsky's models and Anthropic's Claude in the same conversation?

A: Yes. Claude is the host model that decides when to call tools. Plugsky (via MCP) exposes 36 additional models as tools. Claude reads your prompt, picks a Plugsky model via plugsky_models or plugsky_route, and orchestrates the response.

Q: How do I revoke an MCP server's access?

A: Delete its entry from claude_desktop_config.json and restart Claude. For OAuth-authed servers, also revoke the token on the server's dashboard (e.g., plugsky.com/keys).

Q: Is there a UI to manage MCP servers in Claude Desktop?

A: Settings → Developer shows the currently loaded servers and their tools, but adding/editing is still JSON-based. A GUI is on Anthropic's roadmap for late 2026.

Trust & sources

• Author: Mustafa Hasan.
• Last updated: {DATE}.
• References: Claude MCP quickstart, MCP spec 2026-07-28, Plugsky MCP docs.
• Related: [What is MCP](/blog/what-is-mcp) · [Add MCP to Cursor](/blog/add-mcp-to-cursor) · [Best free MCP servers](/blog/best-free-mcp-servers-2026).