Connect an agent

The realpng MCP server gives your agent four tools to check and optimize images, listed in MCP tools. API or MCP says when to use the REST API instead.

Before you startCopy Anchor Link

You need an API key from your account page on a plan with API access. Authentication covers keys and which plans include the API.

Name the key after the agent. Usage lists every check and optimization with the name of the key that ran it and marks it MCP. Right after you create a key, Set up MCP with this key opens the MCP section with that key filled in.

Add the serverCopy Anchor Link

Each config points at the realpng MCP server and sends your key in the X-API-Key header, as Authentication describes. The server is remote and speaks Streamable HTTP, so if a client asks for a transport, pick HTTP.

claude mcp add --transport http realpng \
  https://realpng.com/mcp \
  --header "X-API-Key: rp_live_YOUR_KEY"

Replace rp_live_YOUR_KEY with your key. Then start a new session or restart the app, since clients load the tool list when they start.

Where each config goesCopy Anchor Link

• Claude Code: run the command in a terminal. It adds realpng to the current project. Add --scope user to add it to every project.
• Codex: add it to ~/.codex/config.toml.
• Cursor: add it to .cursor/mcp.json in your project, or to ~/.cursor/mcp.json for every project. Add to Cursor installs the same config with rp_live_YOUR_KEY in it, so replace that in Cursor's MCP settings.
• Claude Desktop: add it to claude_desktop_config.json, opened from Settings, then Developer, then Edit Config. It runs the mcp-remote bridge with npx, so Node.js must be installed. Put your key in the REALPNG_API_KEY entry, then quit and reopen Claude Desktop.

If a JSON file already lists other servers, add the realpng entry beside them.

Confirm it worksCopy Anchor Link

Ask your agent to list its realpng tools. It should name audit_image, request_upload, process_image and get_processing_result. Listing the tools spends no credits.

You can also ask it to check an image by URL. That runs a real check and spends its credits, as Credits and limits shows.

If it does not connectCopy Anchor Link

A missing, wrong or revoked key fails before any tool runs, and so do a plan without API access and a failed payment. The agent then shows a failed connection, and some clients, Claude Code among them, may offer to sign in. realpng has no sign in for MCP, so check the key and your plan instead. Errors lists each cause and its fix.

Credits and limitsCopy Anchor Link

MCP spends the same credits as the API and shares its limits, as Credits and limits explains. audit_image spends a check's credits and process_image an optimization's, while request_upload and get_processing_result spend none.