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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral context: transfers are excluded from the analysis and results are bucketed into periods. It stops short of describing output fields or how partial buckets at range edges are handled.

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?

Three sentences, front-loaded with the core action and scope before the differentiation and the navigation hint. Dense but every clause carries information; the parenthetical page-link sentence is slightly tacked-on but still actionable.

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 no output schema, the description correctly fills the gap by summarizing the return ('actual vs budgeted figures per period bucket'). For a read-only analytical tool with fully documented parameters, an agent has enough to select and call it, though exact response fields remain unspecified.

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 coverage is 100%, so all five parameters are already documented, and the description's fortnightly example essentially restates the interval property's schema text. It adds the useful framing that sub-monthly buckets are the differentiator, but gives no extra detail on date alignment or how interval interacts with period=years.

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 and resource ('Gets the user's budget summary with expense and income analysis') and scopes it ('across all categories (excluding transfers)'). It also explicitly differentiates itself from siblings by claiming to be 'the only analysis tool with sub-monthly buckets', which no other tool name suggests.

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?

Gives a concrete triggering condition — pay-cycle asks like 'what's left over each fortnight' — and names the exact parameter combination that serves it (period=weeks interval=2). It also routes the agent to the follow-up page-link siblings (navigate_to_budget, navigate_to_income_expense) with a stated purpose for each.

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