AI Price Index

ai-price-index-mcp

RoninForge ai-price-index-mcp is a read-only Model Context Protocol server that answers what an AI model's API price was on a given date, with the first-party source that proves it. It is MIT licensed, runs entirely on your machine, and requires no API keys.

Part of RoninForge.org, an independent open-source workshop that keeps dated, reproducible records of the AI developer tooling economy. It serves the open AI Price Index dataset to any MCP client, including Claude Code and Cursor.

Most pricing tools tell an agent what a model costs today. This one also answers what a model cost on a given date, and returns the first-party source URL plus the date that price was last validated, so the agent can cite the number. That point-in-time lookup is the differentiator.

• Zero keys, zero prompts, zero network at runtime. The dated dataset is bundled inline inside the ai-price-index dependency. The server reads it locally and adds nothing to your traffic.
• Read-only. It only looks prices up. It cannot write, configure, or call out.
• Cite-ready. Every result carries source_url, last_validated, confidence, and the CC BY 4.0 attribution string.

Install

Requires Node.js 18 or newer. No build step, no API key.

npx -y ai-price-index-mcp

That command runs the stdio server; an MCP client launches it for you using the config below.

Client configuration

Drop this into your MCP client config. The server speaks stdio.

Claude Code (~/.claude.json or a project .mcp.json), and Cursor (~/.cursor/mcp.json), use the same mcpServers shape:

{
  "mcpServers": {
    "ai-price-index": {
      "command": "npx",
      "args": ["-y", "ai-price-index-mcp"]
    }
  }
}

Or, with Claude Code's CLI:

claude mcp add ai-price-index -- npx -y ai-price-index-mcp

Tools

All tools return structured JSON as text content. Prices are usd_per_mtok (USD per million tokens). Model ids resolve through the dataset's aliases, so short ids work (e.g. claude-opus-4-5 resolves to claude-opus-4-5-20251101).

Tool	Arguments	Returns
current_price	model, provider?	Today's input/output price for a model, with its source.
price_on	model, date (YYYY-MM-DD), provider?	The price in effect on that date (the point-in-time lookup).
compare	models[], date?	Side-by-side input/output prices for several models on one date.
cost_from_usage	model, tokens, date?, provider?	USD value of a token rollup at a point in time, with cache multipliers.
list_models	provider?	Known model ids (optionally one provider), each with its aliases.

tokens for cost_from_usage accepts input, output, cache_read, cache_write_5m, cache_write_1h (all optional, missing counts as 0). Cache read is 0.1x input, cache write is 1.25x (5 minute) or 2x (1 hour).

Pass provider (for example openai, anthropic, google) to disambiguate a bare id that exists under more than one vendor.

Example result

price_on with { "model": "gpt-4", "date": "2024-01-01" }:

{
  "query": "gpt-4",
  "provider": "openai",
  "model": "gpt-4",
  "date": "2024-01-01",
  "covered": true,
  "input": {
    "usd_per_mtok": 30,
    "unit": "usd_per_mtok",
    "effective_from": "2023-03-14",
    "effective_to": null,
    "last_validated": "2023-04-15",
    "confidence": "archived",
    "source_url": "https://web.archive.org/web/20230415223802/https://openai.com/pricing"
  },
  "output": { "usd_per_mtok": 60, "...": "..." },
  "provenance": {
    "dataset": "AI Price Index by RoninForge",
    "data_version": "2026-06-17",
    "license": "CC-BY-4.0",
    "attribution": "AI Price Index by RoninForge (https://roninforge.org/data/ai-price-index/), CC BY 4.0",
    "source": "https://roninforge.org/data/ai-price-index/"
  }
}

How it works

This server is a thin wrapper over the ai-price-index npm library, which ships the dated dataset bundled inline. There is no pricing logic, no separate data layer, and no network call here. The data version a result reports is the dataset release that the installed ai-price-index pins to. To move to newer prices, update that dependency.

Data license and attribution

The price data is from the AI Price Index and is licensed CC BY 4.0. When you publish anything derived from it, attribute it:

AI Price Index by RoninForge (https://roninforge.org/data/ai-price-index/), CC BY 4.0.

The code of this server is licensed MIT (see LICENSE). Data and tooling licenses are tracked upstream in the ai-price-index repository.

Links

• Data page: https://roninforge.org/data/ai-price-index/
• Library: https://www.npmjs.com/package/ai-price-index
• Dataset repo: https://github.com/RoninForge/ai-price-index
• DOI: https://doi.org/10.5281/zenodo.20730241