Runtime

The helpers available inside a tool.

Tools run in an isolated JavaScript context. Use the built-in SDK for network and database calls. You cannot install packages inside a tool.

Inputs and secrets

Value	Use
params	Tool inputs, such as params.userId
env	Server secrets, such as env.API_KEY
console	log(), warn(), and error()

Return a string or a JSON-compatible value. TryMCP sends the result to the client as text.

HTTP

sdk.http() accepts method, url, headers, and body. The default method is GET. URLs must use HTTPS. Private network targets are blocked.

const response = await sdk.http({
  url: "https://api.example.com/items",
  headers: { Authorization: `Bearer ${env.API_KEY}` },
});

if (!response.ok) {
  throw new Error(`API returned ${response.status}`);
}

return response.json();

Replace the example URL with your API. Add API_KEY as a secret.

Response value	Type
response.status	HTTP status number
response.ok	Success boolean
response.headers	Response headers object
response.body()	Raw response string
response.json()	Parsed JSON value

HTTP errors do not throw by themselves. Check ok or status. Call json() only when the body is JSON.

Database

Use sdk.db() to open a connection. The examples use PostgreSQL (pg) and MySQL (mysql2). The database must be reachable from TryMCP. Private network targets are blocked.

const db = await sdk.db({
  type: "pg",
  connection: {
    host: env.DB_HOST,
    port: Number(env.DB_PORT || 5432),
    database: env.DB_NAME,
    user: env.DB_USER,
    password: env.DB_PASSWORD,
  },
});

try {
  return await db.select("orders", { user_id: params.userId });
} finally {
  await db.destroy();
}

Add the five DB_ secrets above and a required string input named userId.

Method	Use
db.select(table, conditions)	Read rows using equality filters
db.query(sql, bindings)	Run SQL with ? value bindings
db.destroy()	Close the connection

Use db.query() for inserts, updates, and deletes. Keep SQL and table names in your code. Pass input values through bindings.

PostgreSQL query results are returned as rows directly. Do not read a .rows property. Use RETURNING when a PostgreSQL write needs to return data.

Lodash

Use sdk.lodash to filter, group, and sort data. template() is disabled.

return sdk.lodash.uniqBy(params.items, "id");

This example needs a required array parameter named items.

Logs

console.log("Tool started");

return { ok: true };

Console messages appear in Output during a run. Do not print secrets or return them to the client.