ck_get_spending_by_merchant

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

The readOnlyHint annotation confirms safety. The description adds the behavioral detail that only debit spend is considered, not credit. However, it does not disclose ordering, whether results are truncated, or response structure.

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, direct sentence with no unnecessary words or fluff. Perfectly concise.

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 is simple with 4 optional params and no output schema. The description is adequate but missing details like ordering direction (e.g., descending by total spend) and whether 'top' is by count or amount. Could be more complete for autonomous usage.

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?

All 4 parameters are described in the schema (100% coverage). The description adds no extra parameter semantics beyond what the schema provides, such as the default for limit or date format.

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 'Return top merchants by total debit spend' clearly states the verb, resource, and scope, distinguishing it from sibling tools like ck_get_spending_by_category.

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 vs alternatives such as ck_get_spending_by_category or ck_list_transactions. The description implies usage for merchant analysis but lacks explicit context.

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