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StringSpec

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Lab measurements of nearly 800 tennis strings: search, compare and get recommendations.

Source code Website Documentation

What can you do with StringSpec?

  • "Which polyester strings are the softest, and what do they cost?"
  • "How fast does Solinco Hyper-G 16 lose tension, and how long will it stay playable?"
  • "Compare RPM Blast 17 with Luxilon ALU Power 16L."
  • "I have tennis elbow and a stiff racquet. What should I string, without natural gut?"
  • "What should I string for more spin on an 18x20 racquet?"

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http stringspec 'https://stringspec.com/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "stringspec": {
            "type": "http",
            "url": "https://stringspec.com/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. StringSpec for Claude and other MCP clients
  2. What you can ask
  3. Tools
  4. Setup
  5. Privacy
  6. Support
  7. License

StringSpec for Claude and other MCP clients

Ask an AI assistant about tennis strings and get answers from lab measurements instead of marketing copy: how stiff a string is, how fast it loses tension, how much energy it returns, how much spin it allows, and which strings suit a player's needs and racquet.

This repository holds:

  • the connection details for the StringSpec remote MCP server at https://stringspec.com/mcp,
  • a Claude plugin that adds that server plus a string-research skill, which teaches Claude how to read the numbers.

The server is run by StringSpec, a database of nearly 800 tennis strings measured on the same machine under the same protocol, so one string's numbers compare fairly with another's. How the numbers are made: methodology.

What you can ask

  • "Which polyester strings are the softest, and what do they cost?"
  • "How fast does Solinco Hyper-G 16 lose tension, and how long will it stay playable?"
  • "Compare RPM Blast 17 with Luxilon ALU Power 16L."
  • "I have tennis elbow and a stiff racquet. What should I string, without natural gut?"
  • "What should I string for more spin on an 18x20 racquet?"

Tools

All tools are read-only (readOnlyHint: true) and need no account.

ToolWhat it answers
search_stringsFilter by name, brand, material, gauge and price; sort by popularity, softest, stiffest, most spin, best tension hold, most power or cheapest. At most 10 strings per call.
get_stringEverything on one string, found by name: every measurement with its percentile in the database, elongation at 40, 51 and 62 lb, an estimated playable life, a tension adjustment, how it ranks for spin, comfort, control, power, tension hold, durability and feel, the closest alternatives, and the retail price.
compare_stringsTwo or three strings side by side, with the comparison page on stringspec.com.
recommend_stringsStringSpec's string finder: a main need and an optional second one, adjusted for the racquet (string pattern, head size, frame stiffness), with a material ruled out if asked. Returns a ranked shortlist with a 0 to 100 fit and the reason each string fits.

Every answer separates measurements from estimates (playable life, tension advice and fit are derived from the measurements) and dates each price.

Setup

Claude (claude.ai, Desktop, mobile)

Settings → Connectors → Add custom connector, then paste https://stringspec.com/mcp. No sign-in is needed.

Claude Code

Install the plugin, which adds the server and the string-research skill:

/plugin marketplace add BigBalli/stringspec-mcp
/plugin install stringspec@stringspec

Or add only the server:

claude mcp add --transport http stringspec https://stringspec.com/mcp
Other MCP clients

Any client that supports remote MCP servers over Streamable HTTP can use https://stringspec.com/mcp with no credentials. The server speaks protocol versions 2026-07-28, 2025-11-25, 2025-06-18 and 2025-03-26 and answers with JSON (no SSE, no sessions).

Privacy

The server receives the tool name and its arguments (for example a string name or "comfort"), uses them to answer, and does not store them. It never sees your conversation or your account. Full policy: stringspec.com/privacy.

Support

Email g@bigballi.com, or see stringspec.com/connect.

License

The contents of this repository are released under the MIT License. The data served by the StringSpec MCP server is not part of this repository and is not covered by that license.

Frequently asked questions

What is StringSpec?

Lab measurements of nearly 800 tennis strings: search, compare and get recommendations.

How do I install StringSpec?

It runs as a remote server. In Claude Code: claude mcp add --transport http stringspec 'https://stringspec.com/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does StringSpec need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is StringSpec open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains StringSpec?

It is published by BigBalli. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.