wordpress-mcp

fields_get_definition

Retrieve a WordPress field group, post type, taxonomy, or options page definition by kind and key for a specific site.

Instructions

Get one definition by kind and key.

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": {
      "site": "<site>",
      "kind": "<kind>",
      "key": "<key>"
    },
    "name": "fields_get_definition"
  }
}

Input Schema

Name	Required	Description
`key`	Yes	Definition key (lowercase letters, digits, underscore), e.g. group_event or event
`kind`	Yes	Definition kind: field groups, post types, taxonomies or options pages
`site`	Yes	Site id (see list_sites)

Schema Changelog

Changes observed during successful MCP inspections.

Addedv3.4.0Oct 1, 2026

TDQS

C2.9/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full disclosure burden. 'Get' implies a read-only operation, but nothing is said about permissions, whether a missing definition errors or returns empty, or how the definition relates to sibling 'definition' resources. This is thin for a tool with zero annotation coverage.

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?

A single short sentence with the lookup keys front-loaded and no waste. It is efficient, though arguably under-specified rather than genuinely concise.

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

Completeness2/5

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

For a 3-required-parameter getter with no output schema and no annotations, the description should clarify what a 'definition' is, what the returned object looks like, and how it pairs with fields_list_definitions/fields_update_definition. None of that is present, leaving an incomplete picture for correct invocation.

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%: key, kind, and site are each documented in-schema, including the enum for kind and the key pattern. The description only restates 'kind and key' and omits the required 'site' parameter, so it adds no meaning beyond the schema — baseline 3.

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+resource ('Get one definition') and constrains it by 'kind and key', which distinguishes it in spirit from siblings like fields_list_definitions and fields_get_schema. However, it never names those siblings, so the differentiation is implicit rather than explicit.

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

Usage Guidelines2/5

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

There is no guidance on when to use this versus fields_list_definitions, fields_get_schema, or fields_get_settings. An agent must infer the selection rule entirely from the tool name.

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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