How to add an MCP server to Cursor (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_models — verify your Cursor connection with one call.

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

Direct answer

To add an MCP server to Cursor in 2026: create .cursor/mcp.json in your project root (or ~/.cursor/mcp.json for global). Add your server under mcpServers with a command (stdio) or url (Streamable-HTTP). Save the file — Cursor hot-reloads. Open the Composer (Cmd+I) and your tools appear in the tools tray. Cursor supports Tools and Resources primitives, plus OAuth 2.1 for remote servers.

Key facts

Project-level config	.cursor/mcp.json in repo root
Global config	~/.cursor/mcp.json
Top-level key	mcpServers
Transports	stdio, Streamable-HTTP
Auth	OAuth 2.1 (preferred), Bearer, stdio env
Primitives supported	Tools, Resources; Prompts partially
Reload	Hot-reload on file save
Best interface	Composer (Cmd/Ctrl+I)
Free tier	Yes — MCP works on all Cursor tiers
Featured MCP directory	Cursor's public MCP catalog

TL;DR

• Cursor stores MCP config in .cursor/mcp.json — one file per project (checked into repo optionally) or global under ~/.cursor/.
• Add a command for local stdio or url for remote hosted.
• Hot-reload on save — no restart needed.
• Tools appear in the Composer's tools tray; call them by name (@plugsky_chat) or let the agent decide.
• Best flow: pair Cursor's editor agent with https://plugsky.com/mcp to bring 36 models + your RAG right into the code.

How it works

Step-by-step: project-level MCP setup

1. In your project root, create .cursor/mcp.json.
2. Add Plugsky as a remote server:

```json

{

"mcpServers": {

"plugsky": {

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

"headers": { "Authorization": "Bearer sk-live-YOUR_KEY" }

}

}

}

```

1. Save. Cursor picks up the change without restart.
2. Open the Composer (Cmd+I / Ctrl+I). The tools tray shows the newly available tools.
3. Try: "Use plugsky_fusion to review this file with 3 different models."

Step-by-step: global MCP setup (works across every project)

Same JSON but at ~/.cursor/mcp.json. Global entries apply to all workspaces. Project-level entries override globals with the same name.

Add Plugsky as a local stdio server

{
  "mcpServers": {
    "plugsky-local": {
      "command": "npx",
      "args": ["-y", "@plugsky/mcp"],
      "env": { "PLUGSKY_API_KEY": "sk-live-YOUR_KEY" }
    }
  }
}

Use local when you want your RAG uploads to include the current workspace files without shipping them over the network.

Composer patterns that work great with Plugsky MCP

• Fusion PR review: @plugsky_fusion review this diff with plugsky-plus, kimi-k2, and glm-4.6; summarize the disagreements.
• Cheapest-first refactor: @plugsky_route pick the cheapest model that can rewrite this to use React 19 hooks.
• RAG-grounded fixes: attach plugsky://collections/design-system via 📎, then ask "rewrite the Button to match our token scale."
• Multilingual doc gen: @plugsky_chat --model plugsky-arabic draft the ADR for this change in Arabic.

What Cursor supports vs the spec

Tools	✅ Full	Auto-invoked or @name in Composer
Resources	✅	Attach via 📎 in chat input
Prompts	⚠️ Partial	Some slash-commands, not full parity with Claude
Sampling	⚠️	Advanced servers can use it — YMMV
Elicitation	⚠️	Mid-tool prompts render as chat messages
Roots	✅	Cursor pins roots to the workspace
OAuth 2.1	✅	Preferred for remote

Common errors and fixes

Tools don't appear	JSON syntax error	Run jq . .cursor/mcp.json — fix if it errors
Tools appear then vanish	Server crashed	Check stderr in Cursor's output panel
401 on remote server	Bearer key missing scope	Regenerate key with the right scopes
Composer says "tool unavailable"	Tool exists but tier locked	Check the server's tier requirements
Slow first response	Cold-start on remote MCP	Warm up: run a small tools/list call once

Comparison — Cursor MCP vs VS Code Copilot MCP vs Windsurf MCP

Config file	.cursor/mcp.json	.vscode/mcp.json (servers key)	~/.codeium/windsurf/mcp_config.json
Hot-reload	✅	✅	✅
OAuth 2.1	✅	✅	⚠️ Bearer preferred
Resources	✅	⚠️	✅
Prompts	Partial	Partial	Partial
Featured directory	✅	✅ (GitHub Marketplace)	⚠️

FAQ

Q: Should I check .cursor/mcp.json into git?

A: Check in the file but keep secrets out. Use ${env:PLUGSKY_API_KEY} and load the real key from an .env.

Q: Can I have both a project and a global .cursor/mcp.json?

A: Yes. Project entries override globals with the same name; new names merge.

Q: Does Cursor support Prompts (slash-commands) from an MCP?

A: Partially — some servers work, some don't. Claude Desktop is more complete on Prompts today; Cursor closes the gap release by release.

Q: How do I attach a Plugsky RAG collection to a Cursor chat?

A: Type @ in the Composer, choose Resources, pick plugsky://collections/{id}. The collection becomes context for the current turn.

Q: Can I use Plugsky's plugsky_code_run sandbox inside Cursor?

A: Yes, once you're on Plugsky's Builder tier or above and the code group is included. The sandbox tool lets Cursor's agent execute Python/Node in an isolated VM.

Trust & sources

• Author: Mustafa Hasan.
• Last updated: {DATE}.
• References: Cursor MCP docs, MCP spec 2026-07-28.
• Related: [Add MCP to Claude](/blog/add-mcp-to-claude) · [Add MCP to VS Code](/blog/add-mcp-to-vscode) · [Best MCP servers](/blog/best-mcp-servers-2026).