Chase overdue invoices on a ladder anchored to the due date: reminder 1, reminder 2, the final notice, with the aging and the day's chase list. You register an unpaid invoice, client, reference, amount in whole minor units, currency, due date, and it returns a DUN-YYYY-NNNN id with the three escalation dates: reminder 1 at due plus 7 days, reminder 2 at due plus 14, the final notice at due plus 21, configurable per invoice. The ladder is anchored to the due date, not to the last letter, so a reminder that goes out twelve days late does not push the final notice back: the client's obligation was fixed by the due date. Letters go out strictly in order, and the late fee is simple interest, pro-rata on a 30-day month, on what is outstanding the day the letter is written, rounded once to the minor unit. letter_render produces the letter as Markdown or a self-contained printable HTML page, letter_sent records that it actually went out, and payment_record lowers what the next letter asks for, with a payment that covers the balance closing the ladder. Nothing is emailed or sent anywhere: the server produces the letter text, and sending it is your act.
In agent mode the ladder is the thing not to recompute: every stage date is the due date plus its gap, never the previous letter's date plus a gap, so a reminder sent twelve days late does not move the final notice. Record the sending with letter_sent and let the server hold the schedule.
| You say | Tool |
|---|---|
| Register INV-1042 to Acme Ltd, USD 1,250.00, due 2026-06-01, late fees at 2% a month. | invoice_register |
| What do I need to send today? | chase_today |
| They paid 500 on the 20th; record it and show me the final notice when it falls due. | payment_record then letter_render |
On the worked chase, USD 125,000 minor units due 2026-06-01 with the default gaps falls due on 06-08, 06-15 and 06-22 whether or not anything was sent, and on 2026-07-01 the fee at 2% per month is exactly 2,500. After a 50,000 part payment the fee on the remainder is 1,500, so the final notice asks for 76,500 and no invented figure more. The unit suite recomputes every one of those by hand.
The file is .vscode/mcp.json, and the key inside it is servers.
| Scope | Path |
|---|---|
| This workspace | <workspace>/.vscode/mcp.json |
| Every workspace | the user profile mcp.json, opened by the MCP: Open User Configuration command |
If you also run Claude Desktop, the shortest path there is one click: dunning-letters.mcpb
from the latest release opens as an extension, with no JSON and no terminal.
VS Code reads its own config, so here it is:
// .vscode/mcp.json (the key is "servers")
{
"servers": {
"dunning-letters": {
"command": "node",
"args": ["/absolute/path/to/mcp-servers/servers/dunning-letters/dist/index.js"]
}
}
}Or from a terminal:
code --add-mcp '{"name":"dunning-letters","command":"node","args":["/absolute/path/to/mcp-servers/servers/dunning-letters/dist/index.js"]}'The node command above wants a built file. From a clone, once:
git clone https://github.com/theluckystrike/mcp-servers.git
cd mcp-servers && npm install
npm run build -w packages/mcp-license -w servers/dunning-lettersThat writes servers/dunning-letters/dist/index.js, and its absolute path is the one argument
the config needs.
The npm packages are not published yet, so the form below returns a 404 today. It is here because it is what the entry becomes the day the publish lands, with nothing else changed:
code --add-mcp '{"name":"dunning-letters","command":"npx","args":["-y","@theluckystrike/mcp-dunning-letters"]}'VS Code asks you to confirm you trust the server and its capabilities before it starts. Nothing runs until you answer.
Nothing is published to npm yet, so the working install paths are the ones above: the .mcpb bundle from the latest release, a clone and build, or the hosted URL.
There is no hosted endpoint for this one yet. MCP Dunning Letters runs locally over stdio with the config above, which is also the only form in which it reads and writes files on your own disk. Thirty of the servers in this collection are served at https://mcp.zovo.one/mcp/<name> over MCP streamable HTTP; https://mcp.zovo.one/mcp/connect lists them and prints a ready URL for each.
The top-level key is "servers", not "mcpServers". A config pasted from a Claude Desktop or Cursor README parses cleanly, contributes no servers, and gives you no error to read, which makes it the most expensive one-word mistake here. Alongside it an "inputs" array holds secrets. The newer Agent Host reads a workspace .mcp.json instead.
Free: Three unpaid invoices chased at once, with all three letters in both formats, the aging summary, the day's chase list and payment recording free on every tier. An invoice that gets paid frees its slot, because the cap is on how many chases run at once, never on the letters or the aging. Pro is $19 once, verified offline.
The key is servers, not mcpServers. A config copied from a Claude Desktop README parses cleanly and contributes nothing. Rename it. On the newer Agent Host, use a workspace .mcp.json instead.
No. code --add-mcp takes the server object on the command line, and MCP: Add Server in the palette asks whether the target is Workspace or Global.
In Chat, behind the tools picker, once the server has started. Adding or changing one raises a prompt asking you to confirm you trust it; if the picker is empty, that prompt is usually still waiting.
MCP Dunning Letters in detail · The same server in Cursor and Windsurf · Every server in VS Code · Guides · VS Code docs · Buy Pro