Create a new account in a YNAB budget by specifying its name, type, and current balance.
Creates a new account
| Name | Required | Description | Default |
|---|---|---|---|
| account | Yes | ||
| 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) |
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states that an account is created, omitting side effects, permission needs, or implications for financial data. For a mutation tool, this is a critical gap with zero behavioral context.
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?
The one-sentence description is concise but under-specified, essentially restating the tool name without earning its place. It lacks front-loaded context or constraints that would help an agent parse the tool's purpose quickly.
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?
This tool creates a financial account with a required plan_id and nested account object, yet the description provides no context about prerequisites, side effects, or relationship to other resources like transactions or categories. The description is woefully inadequate for an agent to call this tool correctly and safely.
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 description adds no meaning to the parameters beyond what the schema already provides. Schema coverage is only 50%, and the description fails to compensate for the undocumented 'account' object, leaving agents to infer the structure solely from the nested schema.
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?
The description 'Creates a new account' is a direct restatement of the tool name 'createAccount', providing no additional detail about scope, parameters, or distinguishing behavior. It does not help differentiate the tool from siblings like createCategory or createPayee beyond the resource name, which is already evident from the tool name itself.
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?
The description offers no guidance on when to use this tool versus alternatives, no prerequisites, and no exclusions. An agent cannot determine context for invoking createAccount, such as whether plan_id must be validated or how it relates to other account operations.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.