arcade-ynab-mcp

by laughnan

Overview Schema Source Related Servers Discussions Admin

Python

Remote

UpdateCategory

Ynab_UpdateCategory

Idempotent

Update a YNAB category's name, note, group, or target. Rename, move, set or remove goals. Only provided fields change.

Instructions

Rename a category, change its note or group, or set or remove its target (goal). Only the fields you pass change. (YNAB's API can't hide or unhide categories.)

Input Schema

TableJSON Schema

Name	Required	Description
`name`	No	New name.
`note`	No	New note. Pass an empty string to clear it.
`plan_id`	No	The YNAB plan (budget) ID. Defaults to 'last-used', the plan the user opened most recently. Use ListPlans to find other plan IDs.
`category_id`	Yes	The category to change.
`goal_target`	No	Target amount in currency units. Creates a 'Needed for spending' target if the category has none.
`remove_goal`	No	Remove the category's target entirely.
`goal_frequency`	No	Make the target repeat monthly, weekly or yearly. Requires goal_target.
`goal_target_date`	No	Target date (YYYY-MM-DD). Can't combine with frequency.
`category_group_id`	No	Move the category to this group.
`goal_needs_whole_amount`	No	true = 'Set aside another' the target each period; false = 'Refill up to' the target.

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Oct 4, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already declare non-destructive, idempotent, open-world semantics, so the bar is lower. The description adds two genuinely useful behaviors beyond them: patch semantics ('Only the fields you pass change') and an API-level limitation ('YNAB's API can't hide or unhide categories') that prevents a failed or misdirected call.

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

Conciseness5/5

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

Two sentences, both front-loaded and zero-waste: capabilities first, then the patch semantics and the hard limitation. Nothing redundant.

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?

With an output schema, full parameter documentation, and annotations covering safety, the description is nearly sufficient. It could still note permission requirements or what happens to unmentioned fields' side effects on the plan, but nothing an agent needs to invoke it correctly is missing.

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%, including cross-field constraints ('Requires goal_target', 'Can't combine with frequency'), so the schema carries the load. The description restates the target/group/note fields at a high level without adding syntax or interaction rules beyond it.

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?

States a specific verb (rename/change/set/remove) against a specific resource (category), and enumerates exactly the mutable surfaces: name, note, group, target/goal. This clearly distinguishes it from Ynab_CreateCategory and Ynab_UpdateCategoryGroup.

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?

Usage is implied (modify an existing category) but never stated explicitly, and no when-not guidance or alternatives are named despite siblings like Ynab_UpdateCategoryGroup and Ynab_CreateCategory being easy to confuse with this tool. The partial-update note is behavior, not selection guidance.

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