ck_get_spending_by_category

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description does add one meaningful behavioral constraint not in the structured fields: only debit transactions are aggregated, excluding credits and transfers. It says nothing about date-range defaults, session requirements, or what happens when parameters are omitted.

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 with the aggregation and the grouping dimension front-loaded. Zero filler and nothing redundant with the tool name.

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 carries some burden for explaining the return shape; it states that results are grouped by category with totals, which is helpful, but says nothing about ordering, category source, or how empty/no-data ranges are represented. Adequate but with a clear gap for an aggregation 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?

Schema description coverage is 100% and all three parameters (account, start_date, end_date) carry their own descriptions, so the schema does the heavy lifting. The description adds no format, default, or interaction detail beyond what the schema already provides, which is the expected baseline here.

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 ('Group ... and return totals') and resource ('debit transactions by category'), which an agent can distinguish from the sibling ck_get_spending_by_merchant by the grouping dimension. It stops short of naming that sibling explicitly, so differentiation is inferential rather than stated.

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 guidance on when to use this versus ck_get_spending_by_merchant, ck_list_transactions, or ck_query_sql, and no mention of required context (e.g., setting a session first). Usage must be inferred entirely from the name and one-line purpose.

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