Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/mcpflow/neon-mcp/mcpgit clone --depth 1 https://github.com/mcpflow/neon-mcpWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00718 | $0.00718 |
| Opus 5 | $0.00359 | $0.00359 |
| Sonnet 5 | $0.00144 | $0.00144 |
| Haiku 4.5 | $0.00072 | $0.00072 |
Grade A, and why
mcp scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
async fetch(request: Request): Promise<Response> { How it starts
The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MCP Server
Project Context
This is a Model Control Protocol (MCP) server that is a minimal wrapper that exposes a few endpoints from the Neon REST API as MCP tools so AI agents can use them.
What is MCP?
MCP is an open protocol that standardizes how applications provide context to LLMs. Think of MCP like a USB-C port for AI applications. Just as USB-C provides a standardized way to connect your devices to various peripherals and accessories, MCP provides a standardized way to connect AI models to different data sources and tools.
MCP Clients are protocol clients that maintain 1:1 connections with servers.
MCP Servers, such as this one, are lightweight programs that each expose specific capabilities through the standardized Model Context Protocol.
Format for defining tools
Edit the src/index.ts file to add new tools. Each method in the MyWorker class becomes an MCP tool that can be used by your Cursor Agent.
For example, here is an example of an MCP tool that returns a friendly greeting:
/**
* A warm, friendly greeting from your new Workers MCP server.
* @param name {string} the name of the person we are greeting.
* @return {string} the contents of our greeting.
*/
sayHello(name: string) {
return `Hello from an MCP Worker, ${name}!`;
}
- The JSDoc comment's first line is the tool's description.
- The
@paramtags are the tool's parameters, with their types and descriptions. - The
@returntag is the tool's return value, with its type.
To add a new tool, just write a new function to the MyWorker class, following the example above. Make sure to add the JSDoc comment in the exact format shown above with the correct types so that the compiler parses it correctly.
How to write functions to wrap APIs
Most of the time, you will be writing tools that return objects that are a lot more complex than simple strings. To comply with the MCP Tools Spec, you must stringify the object to text and return responses in this shape.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 98 lines · 718 tokens per session scan A d651776428b2
mcp is a cursor rule published in the GitHub repository mcpflow/neon-mcp (0 stars, last pushed 1y ago), licensed MIT. It adds 718 tokens to every session, about $0.0036 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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