list_category_groupsRetrieve a YNAB plan's category groups and their current month totals for a quick overview. Use this instead of listing individual categories when you only need group-level summaries.
List the plan's category groups with this month's totals.
Lighter than list_categories when only the overview by group is needed.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds one useful behavioral fact — the results carry this month's aggregated totals rather than raw categories — but says nothing about ordering, empty groups, or plan-month edge cases. Modest value beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences, each earning its place: the first defines output content and scope, the second handles routing. The differentiating detail is front-loaded rather than buried.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no parameters, an output schema to explain return values, and read-only annotations, the description covers everything needed to invoke the tool correctly. The only minor gap is not clarifying whether 'this month' means the calendar month or the selected plan month.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies; the description correctly does not invent parameter discussion.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('List the plan's category groups') plus the scope of the data returned ('this month's totals'). The second sentence explicitly distinguishes it from the sibling list_categories, so an agent can pick between them without opening a schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Names the concrete alternative (list_categories) and the exact condition that selects this one ('when only the overview by group is needed'), including the tradeoff ('lighter'). Both when-to-use and which-sibling-not are explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.