ListPlans

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral detail not in the annotations — result ordering 'most recently modified first' — but discloses nothing about pagination or result-size limits.

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?

A single front-loaded sentence with zero filler; the resource and the ordering constraint are both stated immediately.

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 an output schema present, return values need not be described, and annotations cover safety, so the description is nearly sufficient for a zero-required-parameter list call. The only real omission is pagination/result-size behavior, which a 'list all plans' tool might reasonably need.

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?

Schema description coverage is 100% for the single parameter include_accounts, so the schema already documents it fully. The description never mentions the parameter or its expansion behavior, so it adds no meaning beyond structured data — the baseline 3 applies.

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+resource ('List the user's YNAB plans') and disambiguates YNAB terminology by equating plans with budgets, which helps separate it from siblings like ListAccounts or ListMonths. It does not explicitly name a sibling it is not, so it falls short of a 5.

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 gives no when-to-use, prerequisites, or alternative-routing guidance (e.g., use GetPlanSettings for a single plan's configuration). Usage is only inferable from the verb, which is weak for a tool sharing a namespace with 30+ siblings.

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