gasto

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

No annotations are provided, so the description carries the behavioral burden. It implies a read-only summary operation and enumerates the aggregation dimensions, but it doesn't disclose pagination, whether the data is real-time or cached, or any limitations. The presence of an output schema covers return shape, so the gap is moderate.

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 sentence that front-loads the core purpose (summary of spend in the whole book) and then lists the breakdown dimensions. It is compact and efficient, though the grouped list of dimensions is slightly dense and could benefit from clearer separation.

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?

An output schema is present, covering return values, so the description doesn't need to explain them. The dimensions of the summary are enumerated, making it adequate for a read-only aggregation tool. The main omission is behavioral context (caching, freshness) but that's minor given the output schema.

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 zero parameters, the schema trivially covers 100%, so there is nothing for the description to add about parameter semantics. The baseline of 4 for a zero-parameter tool applies, and the description's focus on what the summary contains is appropriate for a no-input query.

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 states a specific purpose: summarizing spend across the whole book, broken down by mainnet/testnet/invoice, rail, agent, and day. This clear resource (the whole book) and scope distinguish it from siblings like compras (purchases) and fiscal (taxes), though it doesn't explicitly contrast itself with them.

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?

No guidance on when to use this tool versus alternatives such as compras, compra, or fiscal. There is neither an explicit when-to-use nor a mention of when not to use it, leaving an agent to infer the appropriate context from the tool name and description alone.

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