// USE WITH AI //

IronLedger in your AI assistant.

Connect Claude, ChatGPT, Gemini or your coding agent to IronLedger’s free tools: the strength calculators and the program file checker. One address, no account and no key. Your assistant runs the same tested functions as the tools on this site and links each answer back here.

// MCP SERVER ADDRESS //

https://www.ironledger.app/mcp

Streamable HTTP, no sign-in. Listed in the official MCP Registry as app.ironledger/strength-calculators.

// WHAT IT CAN DO //

Seven tools, nothing to sign in to.

Each tool is one tested function, the same one behind the pages on this site.

Tools on the IronLedger MCP server
ToolWhat it does
one_rep_maxOne-rep max calculator
rpe_estimate_maxEstimate one-rep max from a set and its RPE
rpe_target_loadLoad for a target reps and RPE
plate_loadingBarbell plate calculator
warmup_setsWarm-up set calculator
powerlifting_scoreDOTS, IPF GL and Wilks calculator
check_program_fileIronLedger program file checker

What it can’t do: read or change your IronLedger account, see your training history or log a workout. It only calculates and checks what you send it.

// PICK YOUR APP //

Set it up in a minute.

Every step below was checked against the vendor’s own documentation on 17 October 2026. These apps change their menus often; if a step has moved, the linked page has the current one.

Claude (web and desktop)

Chat app
  1. Go to Customize, then Connectors, and click Add custom connector.
  2. Name it IronLedger and paste the server address.
  3. If it asks about authentication, choose No sign-in. Click Add.
  4. In a chat, click +, then Connectors, and turn IronLedger on.

A connector added on the web or desktop also works in the Claude mobile apps.

Claude may ask before it runs a tool. Every IronLedger tool only calculates or checks what you send it, so Always allow is reasonable here.

Who can: Free (one custom connector), Pro, Max, Team and Enterprise. On Team and Enterprise an Owner adds it under Organization settings, then each member clicks Connect.

Checked 17 October 2026 against Claude: Add a connector that isn’t in the directory.

ChatGPT

Chat app
  1. On chatgpt.com, open Plugins, click +, then Add custom MCP server.
  2. Name it IronLedger and paste the server address under Connection.
  3. Leave authentication off: the server needs no sign-in. Tick I understand and want to continue, then click Create as a plugin.
  4. In a new chat, type @ and choose IronLedger.

Who can: Pro (read-only tools, which is all IronLedger has), and Business, Enterprise and Edu, where an admin or owner adds it. OpenAI’s help doesn’t list Plus or Free. Web only, not the mobile apps.

Checked 17 October 2026 against OpenAI Help: Connecting custom MCP servers in ChatGPT.

Gemini (app)

Chat app
  1. On gemini.google.com in a desktop browser, open Settings, then Connected Apps.
  2. Under Custom apps, click Add a custom app, paste the server address and click Next.
  3. In a chat, type @ and choose it.

Google’s help doesn’t say whether a server with no sign-in works, and we haven’t been able to test it from outside the US.

Who can: US only, 18 and over, English, a personal Google account, with Keep Activity on. Added on the web, it also works in the mobile app.

Checked 17 October 2026 against Gemini Apps Help: custom apps.

Claude Code

Coding agent
claude mcp add --transport http --scope user ironledger https://www.ironledger.app/mcp

Leave out --scope user to add it to the current project only.

Who can: Anthropic’s docs set no plan limit for MCP servers.

Checked 17 October 2026 against Claude Code docs: MCP.

Cursor

Coding agent
  1. Add this to ~/.cursor/mcp.json (all projects) or .cursor/mcp.json (one project):
{
  "mcpServers": {
    "ironledger": {
      "url": "https://www.ironledger.app/mcp"
    }
  }
}

Cursor asks before it runs an MCP tool.

Who can: Cursor’s docs don’t say MCP needs a particular plan.

Checked 17 October 2026 against Cursor docs: Model Context Protocol.

VS Code with GitHub Copilot

Coding agent
  1. Run MCP: Add Server from the Command Palette, choose HTTP and paste the server address. Or add this to .vscode/mcp.json:
{
  "servers": {
    "ironledger": {
      "type": "http",
      "url": "https://www.ironledger.app/mcp"
    }
  }
}

Who can: Copilot Free, Pro, Pro+ and Max. Business and Enterprise need the organisation’s “MCP servers in Copilot” policy, which is off by default.

Checked 17 October 2026 against VS Code docs: Use MCP servers.

OpenAI Codex

Coding agent
codex mcp add ironledger --url https://www.ironledger.app/mcp

The Codex CLI and the IDE extension share this setting (~/.codex/config.toml).

Who can: OpenAI’s docs don’t say MCP needs a particular plan.

Checked 17 October 2026 against Codex docs: MCP.

Gemini CLI and Antigravity CLI

Coding agent
gemini mcp add --transport http -s user ironledger https://www.ironledger.app/mcp
{
  "mcpServers": {
    "ironledger": {
      "serverUrl": "https://www.ironledger.app/mcp"
    }
  }
}

For Antigravity CLI, put the second block in ~/.gemini/config/mcp_config.json; it reads serverUrl, not url.

Who can: Gemini CLI now serves paid API keys and Gemini Code Assist. Since 18 June 2026, free and Google One users have Antigravity CLI instead.

Checked 17 October 2026 against Gemini CLI docs: MCP servers; Antigravity docs: MCP.

Devin (formerly Windsurf)

Coding agent
devin mcp add -s user ironledger https://www.ironledger.app/mcp

Windsurf became Devin Desktop in June 2026. Devin’s docs give this command for Devin CLI; the user config file is ~/.config/devin/mcp_config.json.

Who can: Devin’s docs don’t say MCP needs a particular plan.

Checked 17 October 2026 against Devin docs: MCP configuration.

// ADD THE SKILLS //

Teach your assistant when to use it.

Three free skills, each a short SKILL.md: the calculators, a program writer that checks files with the app’s import rules, and a training review that reads the app’s own exports. They live in the public ironledgerapp/skills repository.

Claude (web and desktop)

  1. Download the skill below.
  2. Go to Customize, then Skills, click +, then Create skill, then Upload a skill.
  3. Choose the zip file and turn the skill on.
Download the calculators skill (.zip)

Needs Code execution and file creation turned on under Settings, then Capabilities. Anthropic’s two help pages disagree on whether the Free plan includes skills.

Checked 17 October 2026 against Claude Help: Use skills in Claude.

Claude Code

Installs all three skills and connects the MCP server in one step. Type these in a Claude Code session:

/plugin marketplace add ironledgerapp/skills
/plugin install ironledger@ironledger

Checked 17 October 2026 against Claude Code docs: plugin marketplaces.

Codex, Cursor and other agents

The open skills installer asks which agents to add them to:

npx skills add ironledgerapp/skills

Checked 17 October 2026 against the skills CLI.

The source: github.com/ironledgerapp/skills. The calculators skill is also served at /.well-known/agent-skills/ironledger-strength-calculators/SKILL.md.

// TRY IT //

Prompts to start with.

Using IronLedger, estimate my one-rep max from 140 kg for 5 reps, then tell me what to load for 3 reps at RPE 8.
I’m squatting 405 lb today on a 45 lb bar. Give me an IronLedger warm-up with the plates for each set.
Write me a 4-week upper/lower program as an IronLedger import file, check it with check_program_file, and fix anything it reports before you give it to me.
Score a 600 kg total at 90 kg bodyweight with DOTS and IPF GL.

A program your assistant writes can be checked by hand on the program file checker, then imported in the app.

// FOR DEVELOPERS //

The same tools, without an assistant.