ynab-mcp-server

updateCategory

Update a category's name, note, group, or goal settings in your YNAB budget.

Instructions

Update a category

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>",
      "category_id": "<category_id>",
      "category": "<category>"
    },
    "name": "updateCategory"
  }
}

Input Schema

Name	Required	Description
`plan_id`	Yes	The id of the plan. "last-used" can be used to specify the last used plan and "default" can be used if default plan selection is enabled (see: https://api.ynab.com/#oauth-default-plan).
`category_id`	Yes	The id of the category
`category`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jun 13, 2026

TDQS

C2.3/5.0

Behavior2/5

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

With no annotations provided, the description bears full burden for behavioral disclosure. It does not state whether the update is partial or full, what happens to omitted fields, whether permissions are needed, or what the response contains. Only 'Update' implies mutation.

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

Conciseness3/5

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

The description is extremely concise (4 words), but this brevity sacrifices useful detail. It is not well-structured and does not front-load critical information. A better description could be similarly concise yet more informative.

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

Completeness1/5

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

Given the tool's complexity (3 parameters including a nested object with multiple fields, no output schema, no annotations), the description is severely incomplete. It fails to mention which category attributes can be updated, the effect of omitting fields, or the response format.

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

Parameters2/5

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

Schema description coverage is 67%, which is moderate. The description adds no information about parameters beyond what the schema already provides. It neither compensates for incomplete schema documentation nor clarifies ambiguous fields.

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

Purpose3/5

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

The description 'Update a category' clearly states the verb and resource, but it does not distinguish this tool from siblings like updateCategoryGroup or createCategory. It is minimally clear but lacks differentiation.

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?

No guidance is provided on when to use this tool versus alternatives (e.g., createCategory or updateCategoryGroup). There are no usage contexts, exclusions, or prerequisites mentioned.

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

Deploy Server