describe

describe is the schema introspection tool. AI agents call it first to learn which entities exist, which fields each entity has, and which fields they’re allowed to write — without that, the agent would be guessing at field names.

Signature

{
  "type": "object",
  "properties": {
    "entity": {
      "description": "Entity name or array of names. Omit for a summary of all entities.",
      "oneOf": [
        { "type": "string" },
        { "type": "array", "items": { "type": "string" } }
      ]
    }
  }
}

All arguments are optional.

What it returns

Input	Output
describe()	A summary of every entity (names, one-line descriptions).
describe("contacts")	Full schema for contacts: every field with its type and traits (filterable, sortable, writable, …), the required_for_create rule, and a create_example.
describe(["contacts","deals"])	Full schema for both, returned as a map keyed by entity name.

The writable flags here are the same ones create and update enforce, so a field marked writable: true is one the agent can actually set.

Entities

contacts, companies, deals, actions, notes, calls, meetings. Custom fields are included on the entities they’re defined for.

Example

{
  "entity": "contacts"
}

Truncated response:

{
  "name": "contacts",
  "description": "CRM contacts — people and their company, contact details, and metadata.",
  "fields": {
    "first_name": { "type": "string", "writable": true, "max_length": 50, "filterable": true, "sortable": true },
    "status":     { "type": "string_virtual", "writable": false, "description": "Output only — resolved from status_id." },
    "status_id":  { "type": "string", "writable": true, "groupable": true },
    "emails":     { "type": "embedded_array", "writable": true, "valid_types": ["work", "home", "other"] },
    "created_at": { "type": "time", "writable": false }
  },
  "required_for_create": { "one_of": ["last_name", "company"] },
  "create_example": {
    "first_name": "Alice",
    "last_name": "Smith",
    "company": "Acme",
    "emails": [{ "type": "work", "address": "alice@acme.com" }]
  }
}

Two things worth noting from that shape: required_for_create is a top-level rule, not a per-field flag — here it means a contact needs at least a last_name or a company. And display fields like status are *_virtual and output-only; you write the underlying id (status_id) instead.

Errors

• Unknown entity — describe("foo") returns an error response naming the valid entities. The tool never raises silently.

Scope

mcp. describe returns schema, not records, so it’s available on every authorized MCP session.