ynab-mcp

list_categories

Retrieve all budget categories grouped by category group for a given plan ID. Use this to view and organize spending categories within a YNAB plan.

Instructions

List all categories grouped by category group.

Args: plan_id: The plan ID (use list_plans to find available IDs) exclude_fields: Optional list of field names to exclude from each category group. If omitted, the model's default exclude list is used (see FIELDS.md). Pass [] to return all fields. Pass a custom list to override the default.

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": {
      "plan_id": "<plan_id>"
    },
    "name": "list_categories"
  }
}

Input Schema

Name	Required	Description	Default
`plan_id`	Yes
`exclude_fields`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 7, 2026

TDQS

A4.1/5.0

Behavior3/5

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

With no annotations provided, the description must disclose behavioral traits. It explains the grouping structure and the exclude_fields behavior. However, it does not mention potential limitations like pagination, rate limits, or authorization requirements, which would be helpful for a complete transparency.

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?

The description is concise and well-structured with an Args section. The exclude_fields explanation is slightly verbose but justified given its complexity. No superfluous sentences.

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

Completeness4/5

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

An output schema exists (not shown), so return values need not be detailed. The description covers parameters and behavior adequately. It could mention that the plan must exist, but overall it provides sufficient context for a straightforward list operation.

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

Parameters4/5

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

Schema description coverage is 0%, so the description must add meaning. It does so effectively: for plan_id, it advises using list_plans to find IDs; for exclude_fields, it explains the default, empty array, and custom list options. This adds significant value beyond the schema.

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

Purpose5/5

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

The description clearly states the action ('List all categories') and the output format ('grouped by category group'). It effectively distinguishes from siblings like 'get_category' (single category) and 'list_money_movement_groups' (different resource).

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

Usage Guidelines4/5

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

The description provides clear context: it explains how to find the plan_id using list_plans and details the exclude_fields parameter, including default behavior and override options. Although it doesn't explicitly state when not to use it, the usage context is well covered.

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

Deploy Server