Greenhouse MCP

create_custom_field

Create a new custom field definition for candidates, applications, jobs, offers, openings, or users. Use it to add admin-only fields for tracking extra hiring data.

Instructions

Create a new custom field definition. Write operation — admin only.

Defines a new field available on candidates, applications, jobs, offers, openings or users.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "name": "<name>",
      "field_type": "<field_type>",
      "value_type": "<value_type>"
    },
    "name": "create_custom_field"
  }
}

Input Schema

Name	Required	Description
`name`	Yes	Display name for the custom field
`options`	No	Initial dropdown options for select fields: [{name, sort_order}]
`private`	No	If true, only visible to users with private field access
`field_type`	Yes	Entity: candidate, application, job, offer, opening, user_attribute
`value_type`	Yes	short_text, long_text, yes_no, single/multi_select, currency, date, number, url, user, currency_range, number_range
`description`	No	Helper text shown beneath the field label
`generate_email_token`	No	If true, generates an email token for this field

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed7 schema fields changedv0.5.0Oct 5, 2026

addedInput schema / properties / description

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Helper text shown beneath the field label",
+  "title": "Description"
+}

addedInput schema / properties / field_type / description

Added value: +"Entity: candidate, application, job, offer, opening, user_attribute"

addedInput schema / properties / generate_email_token / description

Added value: +"If true, generates an email token for this field"

addedInput schema / properties / name / description

Added value: +"Display name for the custom field"

addedInput schema / properties / options

Added value: +{
+  "anyOf": [
+    {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "type": "array"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Initial dropdown options for select fields: [{name, sort_order}]",
+  "title": "Options"
+}

addedInput schema / properties / private / description

Added value: +"If true, only visible to users with private field access"

addedInput schema / properties / value_type / description

Added value: +"short_text, long_text, yes_no, single/multi_select, currency, date, number, url, user, currency_range, number_range"

Addedv0.3.4Apr 15, 2026

TDQS

B3.4/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It usefully discloses that this is a write operation requiring admin privileges, but says nothing about reversibility, whether the field name must be unique, side effects on existing records, or rate/validation constraints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with the operation and then the critical admin constraint. No filler, though the line-broken entity list adds little and could be tighter.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and the admin/write framing covers the safety profile. Still, for a 7-parameter creation tool with several sibling field-management tools, the description omits how it relates to those siblings and any uniqueness/validation behavior an agent should anticipate.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all seven parameters are documented in the schema itself, including the field_type entity list and value_type vocabulary. The description adds no parameter detail beyond repeating the entity list already present in field_type's schema description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Create a new custom field definition') and lists the entity surfaces the field can attach to, which clarifies scope. It is distinguishable from list_custom_fields and get_custom_field, though it never explicitly names its mutation siblings (update_custom_field, delete_custom_field, create_custom_field_options).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

'Write operation — admin only' gives a prerequisite, which is real guidance. However, there is no when-to-use vs. when-not guidance relative to the crowded sibling set of custom-field tools (e.g., create_custom_field_options for dropdown values, update_custom_field for existing definitions).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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