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Cursor has first‑class support for remote MCP servers. Once Grain is wired up, the Cursor agent (and Composer) can look up events, run queries, and investigate funnels without leaving the editor — useful when you’re shipping a fix for a conversion drop and want the data right next to the code.

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Setup

Cursor reads MCP servers from a JSON file. You pick where to put it:
  • Global — ~/.cursor/mcp.json in your home directory. Available in every project you open.
  • Project — .cursor/mcp.json in the repo root. Commit it if you want every teammate to inherit the same MCP servers.
1

Create the config file

mkdir -p ~/.cursor
touch ~/.cursor/mcp.json
2

Add the Grain server

Paste this into mcp.json:
{
  "mcpServers": {
    "grain": {
      "url": "https://grainql.com/api/mcp"
    }
  }
}
That’s the whole config. Grain handles client registration and PKCE automatically — you do not need to supply a client_id, a secret, or an Authorization header.
3

Reload and authorize

Open Cursor Settings → MCP (or Settings → Tools & MCP depending on version). You should see grain listed with an Authorize button. Click it.Cursor opens Grain’s consent screen in your browser. Pick the workspace, review the scopes, and click Authorize.
Back in Cursor, the grain server switches to a green “Connected” state and the tool count appears (11 tools if you granted all scopes).
4

Ask the agent something

Open Cursor’s chat or Composer and try:
@grain What’s my top traffic source for the landing page I’m editing?
Cursor will call grain.query, and — because it knows the file you’re in — can even filter by the right page property automatically.
Prefix your prompt with @grain to hint that you want the Grain tools used. Cursor normally picks the right tool on its own, but the hint reduces round‑trips on ambiguous questions.

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Project rule for consistent prompts

Adding a short project rule helps Cursor route analytics questions to Grain without you having to remember the tool names. Create .cursor/rules.md: 
# Grain analytics rule

When the user asks about traffic, conversions, events, funnels, visitor
behavior, or anything analytics‑related:

1. Prefer Grain MCP tools over web search or assumptions.
2. Call `grain.events.list` first on unfamiliar workspaces to learn what
   events exist.
3. For "why did X change" questions, use `grain.query.compare` (period over
   period) before jumping to investigation tools.
4. For drop‑offs in a Track (start → goal funnel), call
   `grain.track.analyze`, then `grain.sessions.cluster` on the biggest
   drop to find representative sessions.
5. Cite the Grain dashboard URL returned in the tool's `citations` field
   so the user can verify.
Rules are optional — Cursor works fine without one — but they pay for themselves the second time someone on your team asks “why is conversion down?”

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Good prompts to try

Before I refactor this checkout page, show me the Track for checkout_started → checkout_completed over the last 30 days and flag the biggest drop‑off step.
Uses grain.track.analyze.
Did my last deploy break any events? Compare event volumes this week to last week and list anything that dropped more than 50%.
Uses grain.query.compare.
A user says signup is broken on Safari. Count signup_failed events in the last 24h, grouped by browser, and tell me if Safari is an outlier.
Uses grain.query with a browser group‑by.

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Troubleshooting

Almost always a JSON typo. Validate mcp.json with a linter — a trailing comma is the usual suspect. Then click Reload in the MCP panel.
Cursor caches the server list. Toggle the server off and on, or fully restart Cursor. If it still misses, check that the url value is exactly https://grainql.com/api/mcp — no trailing slash, no /mcp/ path variations.
You probably approved mcp:read only. Revoke Grain from Settings → Connectors and reconnect; the consent screen will re‑prompt for the full scope set.
Put mcp.json in .cursor/ (not ~/.cursor/) and commit it. Each teammate still goes through their own OAuth flow — tokens are never written to the config file.

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Next steps

Tool reference

Every tool Grain exposes and what it returns.

Security & scopes

How to audit and revoke connections.

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References