Use Centering Lab in ChatGPT and Claude

Centering Lab measures collectible card centering and explains the centering ceilings published or interpreted for PSA, BGS, CGC and SGC. The website, API, GPT and MCP tools use the same measurement engine and standards. A centering ceiling is the highest grade allowed by centering alone, not a prediction of the final grade.

MCP tools for AI assistants

Remote server URL: https://centeringlab.com/mcp. Streamable HTTP, no API key.

• grade_centering: known front/back ratios, maximum centering ceilings and the limiting face/axis. Missing axes or the other face may lower the result.
• get_centering_standards: threshold tables with links, verification provenance and official/interpreted/approximate status. TAG is not included.
• measure_card_centering: one photo with explicit front/back, L/R and T/B ratios, uncertainty, confidence and warnings. Needs-review results have no grade ceilings.

Claude

In Claude's connector settings, add a custom connector named Centering Lab, with URL https://centeringlab.com/mcp. Enable it in your conversation. Custom connector availability depends on your plan/workspace. Claude custom connector guide.

ChatGPT developer mode / app

In ChatGPT, open Settings → Security and login and turn on Developer mode. Go to Plugins, select the plus button and add a connection named Centering Lab with URL https://centeringlab.com/mcp. This service requires no authentication. Add the connection from the tools menu in a new conversation. Availability and labels can depend on your account and workspace policy. OpenAI's connection guide.

Cursor

Add this entry to the mcpServers object in .cursor/mcp.json (project) or ~/.cursor/mcp.json (global), then enable it in Cursor's MCP settings:

{
  "mcpServers": {
    "centering-lab": { "url": "https://centeringlab.com/mcp" }
  }
}

Claude Code

claude mcp add --transport http centering-lab https://centeringlab.com/mcp

Use claude mcp list or /mcp to check the connection. For availability across projects, add --scope user to the installation command.

Photos and privacy

Many AI clients cannot forward a photograph attached in chat to a remote MCP tool. Use a public HTTPS image URL or base64 if your client supports it; otherwise measure on the website. Known ratios and standards do not need an image.

The website measures locally: your photo stays on your device. API/MCP/GPT measurements receive the photo on our server, process it in memory and discard it. The assistant provider has its own policy for your chat attachment. See privacy.

Centering Lab is not affiliated with PSA, Beckett, CGC, SGC or TAG. Thresholds marked interpreted or approximate should be treated as such; card condition and the grader's assessment still determine the final grade.