Summarise spending

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower, yet the description adds real context: local analysis, the default inclusion/exclusion set (settled + pending, excluding internal space moves), and a request-limit constraint for long ranges. It stops short of mentioning pagination or auth requirements.

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?

Two dense sentences: purpose first, defaults second, with the request-limit note as a trailing qualifier. No sentence is wasted and every clause carries operational information.

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?

For an 8-parameter, all-optional tool with no output schema, the description covers purpose, grouping semantics, defaults and range constraints well. It only lightly indicates the returned shape (the 'in/out/net' hint) and gives no sense of result structure for the other groupings.

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 baseline is 3, but the description adds genuine meaning beyond the schema: the month grouping returns 'in/out/net' (which the schema never states, and which explains why direction is ignored), and it clarifies counterparty means merchant/payee. That is additive semantics rather than restatement.

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 ('Analyses') and resource ('transactions') plus the exact aggregation dimensions (spending category, counterparty, month). The aggregation framing clearly separates it from listing siblings like list_transactions and find_recurring_payments without needing to name 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?

The default scope ('this calendar month so far, money out only, settled + pending') implicitly frames typical usage, and 'One API request for ranges up to a year' hints at when this is the efficient choice. However, it never names an alternative tool or states when NOT to use it, so guidance remains inferred rather than explicit.

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