get_spending_summary

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

With no annotations, the description carries the transparency burden. It discloses that only transactions with amount < 0 are considered, dates are inclusive, and custom periods require start/end dates. However, it does not state that the operation is read-only, nor does it describe the output structure or any side effects, leaving room for ambiguity.

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?

The description is concise and well-structured: a one-sentence purpose followed by parameter details. Every sentence contributes value, and the format makes the information easily scannable for an agent.

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 tool has 4 parameters, no output schema, and no annotations. The description documents parameters well but does not explain what the summary output looks like (e.g., totals, counts, breakdown structure). An agent may not know how to interpret the returned data, which is a notable gap given the lack of an 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?

Schema description coverage is 0%, but the description fully explains all parameters: allowed values for period and group_by, the requirement for start_date/end_date when period='custom', and the ISO 8601 format with inclusive behavior. This adds essential meaning beyond the bare schema.

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 identifies the tool as summarizing expense transactions (amount < 0) over a period, grouped by category or source. It distinguishes itself from sibling tools (ping, add_transaction, categorize_transaction) by focusing on aggregate read-only analysis rather than mutations or health checks.

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 provides clear context for when to use the tool (summarizing expenses) and explains the period and grouping options. It does not explicitly name alternatives or state when not to use it, but the sibling context and the explanatory parameter notes make the intended usage clear.

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