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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds what the tool returns, which is useful behavioral context beyond the annotations. It does not mention any limitations, but none are obviously needed for a read-only summary.

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, well-structured sentence that lists all key outputs without redundancy or extra fluff. The most important information is front-loaded.

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?

The output schema exists (per context signals), so return values need not be detailed in the description. The description covers the key contents, and the schema covers parameters. No critical information is missing for an agent to decide whether to invoke this tool.

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?

Both parameters (level and period) are fully described in the input schema with enum names and defaults (schema coverage 100%). The description adds no additional meaning beyond what the schema already documents, so the baseline of 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?

The description clearly lists the outputs: income, expenses, net savings, category breakdown, and merchant frequency for a period. This specifies a distinct resource and differentiates it from transaction-level tools like list_transactions.

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 purpose implies this tool is for period-level summaries, but there is no explicit guidance on when to use it over alternatives or any exclusions. Usage is inferred from the description rather than stated.

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