YNAB MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does add some useful context: it mentions server-side filtering for 'before_date,' provides a date range example, notes a default for 'max_results,' and describes the return structure including truncated flags. However, it lacks information about permissions, rate limits, or error conditions.

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 description is well-structured with clear sections (Args, Returns) and uses bullet points effectively. Every sentence adds value, though the date range example could be slightly more concise. Overall, it's appropriately sized for an 8-parameter tool.

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?

Given the tool's complexity (8 parameters, no annotations, but with output schema), the description is quite complete. It thoroughly documents all parameters and their semantics, and while it doesn't need to explain return values (output schema exists), it usefully summarizes what's returned. The main gap is lack of behavioral context like permissions or error handling.

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?

With 0% schema description coverage, the description fully compensates by providing clear explanations for all 8 parameters. It explains defaults (budget_id, max_results), date format examples, filtering logic (type options, server-side filtering), and practical usage examples like date ranges.

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 clearly states the tool's purpose as 'Search and list transactions with optional filters,' which is a specific verb+resource combination. However, it doesn't explicitly differentiate this from sibling tools like 'get_scheduled_transactions' or 'get_accounts,' which prevents a perfect score.

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 provides no guidance on when to use this tool versus alternatives like 'get_scheduled_transactions' or 'get_accounts.' It mentions that 'budget_id' uses a default if omitted, but this is parameter-specific and doesn't constitute overall usage guidance for the tool.

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