little-green-light-mcp

A read-only MCP server for the Little Green Light donor CRM. Any stdio MCP client can use it to look up constituents, list gifts in a date range, or fetch one person's giving history.

The server name is lgl-mcp. How you register it depends on the host — see Setup.

Read-only by construction

This server has no create, update, or delete tools — not disabled, absent. lgl.js exposes only a GET request function; there is no code path anywhere in this project that can mutate a donor record. Run npm run audit:readonly after any change to confirm mechanically.

Any future write path (e.g. syncing donations) belongs in LGL's own reviewed Integration Queue, not here.

Related MCP server: SQL Server MCP

Setup

1. Get an API key from LGL: Settings → Integration Settings → LGL API.

2. Put it in ~/.config/lgl-mcp/env (already created, chmod 600):

   LGL_API_KEY=your-key-here

   Alternatively, add a macOS Keychain item named lgl-api-key, or set the LGL_API_KEY environment variable for a one-off run. The key is never logged, committed, or echoed in error messages.

3. Install dependencies (already done on first checkout):

   npm install

4. Point a stdio MCP host at this server. The command is node; the argument is the absolute path to index.js:

   {
     "command": "node",
     "args": ["/absolute/path/to/little-green-light-mcp/index.js"]
   }

   Wrap that in whatever config shape your host uses (mcpServers, a top-level server map, and so on). No extra env vars are required if the key is in ~/.config/lgl-mcp/env or Keychain. Set LGL_API_KEY in the host's env block only for a one-off override.

Tools

Every tool accepts verbose: true to get the full LGL object instead of the trimmed summary. Compact constituents include name, email, phone, and city/state. Giving dates and lifetime total are only on get_constituent. Compact gifts include date, amount, fund_id, note, and donor name (when expanded). List responses that are capped include a note field saying how many results were omitted — nothing is silently truncated.

Confirmed query syntax

LGL's /constituents/search and /gifts/search take q[]=field=value pairs, not free text — this was undocumented for several fields and confirmed by probing a live account:

• Constituents: name=<text> (LGL's own documented example) or eaddr=<email> for an exact email match (undocumented; guesses like email=/email_address= were rejected).

• Gifts: date_from=YYYY-MM-DD / date_to=YYYY-MM-DD (confirmed real filters — an out-of-range date zeroes total_items). Multiple q[] entries AND together.

• Gifts have no fund or amount filter on this endpoint — fund_id, fund, fund_ids, campaign_id, amount_from, amount_to were all tried and rejected as unknown parameters. search_gifts doesn't expose these; filter results client-side on fund_id / note if needed.

• A gift's donor name only appears when the request includes expand=first_name,last_name,org_name — LGL doesn't nest a constituent object in the gift response otherwise.

• get_constituent's giving totals (first/last gift date, lifetime amount) aren't returned by LGL on the constituent object at all — they're computed here from that constituent's own gift history, paged to completion. A constituent with no gifts returns lifetime_amount: 0. A safety cap still applies (10,000 gifts); the response says so if it is hit.

Development

npm run inspect          # MCP Inspector — exercise tools interactively
npm run audit:readonly   # mechanical check: no POST/PATCH/PUT/DELETE anywhere

Rate limits

LGL allows 300 API calls per 5-minute window. lgl.js throttles internally (sliding window) and retries with backoff on 429/5xx, so a broad question that fans out into many calls degrades gracefully instead of erroring.