MCP server for Citable — pay-per-call SEO and AI-visibility data. Each tool pays for itself in USDC on Solana over x402 from a keypair on your machine. No account, no API key, no subscription. $0.005–0.30 per call; failed calls are never charged.

Install

Claude Code

claude mcp add citable -- npx -y citable-mcp
# or the plugin, which adds eight skills on top:
/plugin marketplace add zaialamm/Citable
/plugin install citable@citable

Codex

codex mcp add citable -- npx -y citable-mcp

Cursor / Claude Desktop / any MCP client — mcp.json:

{
  "mcpServers": {
    "citable": {
      "command": "npx",
      "args": ["-y", "citable-mcp"],
      "env": { "CITABLE_MAX_PRICE": "0.30" }
    }
  }
}

Requires Node ≥ 20.18. Bun works too: bunx citable-mcp.

Wallet

Nothing to set up first. On its first start the server creates ~/.config/citable/agent.json — a keypair only it uses, separate from anything you keep money in. citable_prices shows the address; send it a few dollars of USDC on Solana mainnet (no SOL needed — the x402 facilitator pays network fees). Walkthrough: https://citable.run/docs/wallet

Config

Env	Default	Meaning
`CITABLE_WALLET`	`~/.config/citable/agent.json`	Solana keypair JSON path (or the JSON byte array itself) holding USDC on mainnet; created on first run if missing
`CITABLE_MAX_PRICE`	`0.30`	refuse any single call priced above this many USD; nothing is signed
`CITABLE_API`	`https://citable.run`	base URL (`http://localhost:3000` for a local Citable)

No SOL is needed — the x402 facilitator pays the network fee. Fund the keypair with mainnet USDC.

Tools

Tool	Price	Returns
`citable_prices`	free	endpoints, prices, this wallet, network, spend cap — call first
`citable_keyword_suggest`	$0.005	autocomplete expansions and questions from Google, YouTube, Bing
`citable_onpage_audit`	$0.01	citability score, 20 checks, ordered `topFixes[]`
`citable_rank_check`	$0.012	Google position of a domain for a keyword + top 10
`citable_keyword_research`	$0.06	one seed → keywords + questions with volume, CPC, difficulty, intent
`citable_keyword_ideas`	$0.05	seed → related keywords with volume, CPC, difficulty, intent
`citable_keyword_metrics`	$0.03	volume, CPC, difficulty, intent for 1–20 keywords
`citable_ai_visibility`	$0.15	which AI engines cite a domain for a prompt, and who they cite instead
`citable_top_cited_pages`	$0.22	the domain's pages AI answers cite most, with AI search volume
`citable_citability_report`	$0.30	audit + AI visibility + top cited pages in one call

Every paid result carries _payment.transaction (the on-chain settlement). Calls above the cap or without funds return a structured error and pay nothing.

How a call works

The tool requests the endpoint; Citable answers 402 with the price, USDC mint and pay-to address.
The server signs a USDC transfer for exactly that amount (only if ≤ CITABLE_MAX_PRICE) and retries with the payment header.
The facilitator settles it on Solana (~400 ms) and the endpoint returns 200 with JSON.

The keypair is read from disk and used only to sign these transfers. Nothing else leaves your machine.