# Use Stack Facts from Claude Code, Cursor or Codex (MCP)

Updated 2026-10-12. Stack Facts is an MCP server (Streamable HTTP) at `https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/mcp`. No account and no API key: add the URL to your client and the tools appear.

## Claude Code

```sh
claude mcp add --transport http stackfacts https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/mcp
```

Or, for everyone on a project, in `.mcp.json` at the project root:

```json
{
  "mcpServers": {
    "stackfacts": {
      "type": "http",
      "url": "https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/mcp"
    }
  }
}
```

## Cursor

In `.cursor/mcp.json` (one project) or `~/.cursor/mcp.json` (every project):

```json
{
  "mcpServers": {
    "stackfacts": {
      "url": "https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/mcp"
    }
  }
}
```

## Codex

```sh
codex mcp add stackfacts --url https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/mcp
```

Or in `~/.codex/config.toml`:

```toml
[mcp_servers.stackfacts]
url = "https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/mcp"
```

## What the tools do

- Free tools answer in the client: stackfacts_preview, stackfacts_try, stackfacts_index, stackfacts_validate, stackfacts_manifest, stackfacts_keys.
- Paid tools: stackfacts_eol_product, stackfacts_eol_cycle, stackfacts_eol_check, stackfacts_eol_image, stackfacts_eol_snapshot, stackfacts_kev_lookup, stackfacts_kev_check, stackfacts_kev_changes, stackfacts_kev_snapshot, stackfacts_models_lookup, stackfacts_models_estimate, stackfacts_models_cheapest, stackfacts_models_changes, stackfacts_models_snapshot, stackfacts_stack_check, stackfacts_osv_check, stackfacts_preflight, stackfacts_cve_lookup, stackfacts_stack_watch. Each answers with an x402 offer (isError) holding the price and the URL: send that HTTP request again with a PAYMENT-SIGNATURE header from any x402 v2 client to get the signed answer. MCP itself takes no payment.
- Every tool with its input schema and an example answer: [llms-full.txt](https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/llms-full.txt). The server card: [/.well-known/mcp/server-card.json](https://g5joilnmeep4ntz3nwezxt5dmu.srv.us/.well-known/mcp/server-card.json).

Data is provided as is, without warranty of any kind. Payments are final. Every dataset is normalised (modified) from the sources named here, and no source endorses this service.