Formul.io MCP Server

Tools the assistant gets

23 tools, grouped by what they do. Read-only tools are always safe; create, edit and delete tools are gated by the scopes you grant.

Option A — Claude.ai web Recommended · no key

The easiest path. Claude.ai runs the whole OAuth flow for you.

1. 1 Open claude.ai and go to Settings → Connectors.
2. 2 Click Add custom connector.
3. 3 Name it Formul.io and paste the Remote MCP server URL below. Leave OAuth Client ID and Secret blank — they are discovered automatically.
4. 4 Click Add. Claude.ai redirects you to Formul.io to authorize.
5. 5 Log in if prompted, review the requested permissions, and click Allow.
6. 6 Start a new chat and ask Formul.io something — see the example prompts below.

Option B — Claude Desktop API key

For Claude Desktop or any client that uses a static bearer token.

1. Create an API key

Log in to Formul.io, open Settings → Security, and create an API key. Pick only the permissions you need:

• Run formulation calculations
• Read your recipes
• Create and modify your recipes
• Search ingredient database
• Diagnose recipe issues

2. Add it to your config

Edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\):

{
  "mcpServers": {
    "formulio": {
      "url": "https://api.formul.io/mcp",
      "headers": {
        "Authorization": "Bearer fio_YOUR_KEY_HERE"
      }
    }
  }
}

Restart Claude Desktop — the Formul.io tools appear in the tool list.

Option C — Custom agents & OAuth 2.1

For your own MCP client or programmatic access. Authenticate with an API key (Bearer fio_…) or an OAuth 2.1 access token.

Transport

OAuth 2.1 endpoints

Public-client PKCE (authorization_code). No client secret. Access tokens last 1 hour; refresh tokens rotate on use.

Quick start

# 1. Register your client once
curl -X POST https://api.formul.io/api/v1/oauth/register \
  -H "Content-Type: application/json" \
  -d '{
    "client_name": "My App",
    "redirect_uris": ["https://myapp.example.com/callback"],
    "grant_types": ["authorization_code", "refresh_token"],
    "scope": "calculate recipes:read ingredients:read"
  }'
# -> { "client_id": "...", "client_secret": null }

# 2. Send the user to authorize (PKCE, S256)
https://app.formul.io/oauth/authorize
  ?client_id=YOUR_CLIENT_ID
  &redirect_uri=https://myapp.example.com/callback
  &response_type=code
  &scope=calculate+recipes:read+ingredients:read
  &code_challenge=BASE64URL(SHA256(code_verifier))
  &code_challenge_method=S256
  &state=RANDOM_STATE

# 3. Exchange the code for tokens
curl -X POST https://api.formul.io/api/v1/oauth/token \
  -d "grant_type=authorization_code" \
  -d "code=AUTH_CODE" \
  -d "redirect_uri=https://myapp.example.com/callback" \
  -d "client_id=YOUR_CLIENT_ID" \
  -d "code_verifier=YOUR_VERIFIER"
# -> { "access_token": "...", "refresh_token": "...", "expires_in": 3600 }

# 4. Call the MCP server
curl -X POST https://api.formul.io/mcp \
  -H "Authorization: Bearer ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"tools/list","id":1}'

Scopes

Grant only what the assistant needs. Each tool requires a scope; without it the call is refused.

Try these once connected

The assistant works against your own account.

Troubleshooting