AGENTS · MCP

Built for agents, not just apps.

openappend ships as an MCP server, so Claude and any MCP-capable agent can query ~971M phones and 380.8M people conversationally — discover the schema, size an audience for free, then pull only the records it commits to. Generate your config below, or point a crawler at /llms.txt.

GENERATOR

MCP server config

Your API keyPasted here only — it is templated into the config in your browser and never sent anywhere. Don't have one yet? Grab a free trial key from Get API key.

Tools to expose

Add this to your claude_desktop_config.json, then restart Claude Desktop.

claude_desktop_config.jsonjson

{
  "mcpServers": {
    "openappend": {
      "command": "npx",
      "args": [
        "-y",
        "@openappend/mcp"
      ],
      "env": {
        "OPENAPPEND_API_KEY": "oa_live_YOUR_API_KEY",
        "OPENAPPEND_BASE_URL": "https://api.openappend.com/v1"
      }
    }
  }
}

Where's the package?

@openappend/mcp is the documented client wrapper — the portal ships only the config, not the package. The stdio server and the remote SSE endpoint speak to the same https://api.openappend.com/v1 and are gated by the same bearer key.

TOOLS · 5

What the agent gets

MCP tool	REST endpoint	Cost	Purpose
people_fields	GET/v1/fields	FREE	Discover every filterable + returnable field before building a query.
people_count	POST/v1/people/count	FREE	Size an audience. Free — dial filters until the count is right.
people_search	POST/v1/people/search	METERED	Return matching records. reveal:false is free; reveal:true bills per record.
email_to_phone	POST/v1/email-to-phone	METERED	Reverse an email to callable, DNC-scored phones. 1 credit per hit.
phone_to_email	POST/v1/phone-to-email	METERED	Reverse a phone to email(s). 1 credit per hit, misses free.

QUICKSTART

How an agent should drive it

Three moves, in order. The whole point of people_fields is that an agent that can read it can compose any count or search — no hard-coded schema.

Install the MCP server

Use the generator above, or add it in one line:

bash

claude mcp add openappend \
  --env OPENAPPEND_API_KEY=oa_live_… \
  -- npx -y @openappend/mcp

Discover the fields

The agent calls people_fields first to learn what it can filter and return — categories, operators, and ordinal bands — then composes from that.

system nudgebash

# What an agent tells the model:
Use openappend. First call people_fields to learn the schema,
then people_count to size, then people_search with reveal:false
to qualify before spending a credit.

tool calljson

{
  "tool": "people_fields",
  "arguments": {}
}

Count free, then reveal what you commit to

Size the audience for $0, qualify with reveal:false (records + contact counts, still $0), then flip reveal:true to pull contacts — billed only for the records you actually take.

1 · count (free)json

{
  "tool": "people_count",
  "arguments": {
    "filters": {
      "state": "IL",
      "city": "Chicago",
      "age": { "between": [30, 55] },
      "home_owner": true,
      "line_type": "mobile",
      "dnc": false
    }
  }
}
// → { "data": { "count": 128450 }, "meta": { "credits_used": 0, ... } }

2 · qualify → revealjson

{
  "tool": "people_search",
  "arguments": {
    "filters": { "state": "IL", "city": "Chicago", "line_type": "mobile", "dnc": false },
    "fields": ["first_name", "last_name", "address", "phone_count"],
    "reveal": false,
    "limit": 100
  }
}
// reveal:false → qualifying fields + contact COUNTS, $0.
// Re-run with "reveal": true to pull contacts — 1 credit per record.

The qualify-then-pay pattern

count (free) → search reveal:false (free — see who matches and how many contacts each has) → search reveal:true (1 credit per record). An agent never spends a credit to explore, only to deliver.

FOR CRAWLERS & AGENTS

/llms.txtConcise plain-text summary — base URL, endpoints, auth, billing. The one-fetch orientation for an agent./llms-full.txtThe entire API contract flattened to plain text — every endpoint, field, operator, and error in one document./openappend/docsThe full human reference — envelope, filter grammar, ordinal bands, views, and errors, portal-styled.Playground · Agent modeBuild a query in the UI and copy it out as the exact MCP tool call — no key required to try.