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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful scope context by saying 'personal' (not group) and by enumerating the returned sections, but says nothing about permissions, currency behavior, or empty-month handling.

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 18-word sentence that front-loads the verb, resource, scope, and returned fields with zero filler. Nothing needs trimming and nothing is buried.

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 usefully enumerates the summary sections, partially compensating for the missing return contract. However, with three parameters at 0% schema coverage and no explanation of the currency parameter's format or default, the definition is incomplete for calling the tool correctly.

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 0%, so the description carries the full parameter burden and fails to: 'currency' is only constrained to a 3-character string with no indication that it is an ISO 4217 code, whether it is optional, or what happens if omitted. The 'year'/'month' parameters are documented only by numeric ranges in the schema, with no statement that they are required or how the month is interpreted.

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 ('Get') and resource ('personal finance summary for a month') and enumerates the returned content (income, expenses, savings, budget status). It distinguishes itself from group-oriented siblings via 'personal', but never names or contrasts with the closest siblings like get_user_balance_summary or get_category_analytics.

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?

There is no explicit guidance on when to use this over get_user_balance_summary (cumulative balances) or get_category_analytics (categorical breakdown). The monthly framing implies a use case, but the agent must infer which summary tool is appropriate for a given request.

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