Get merchant summary

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

Annotations already declare readOnlyHint=true, so the safety profile is known. The description adds useful behavioral context about the anonymous cohort benchmark being null when unavailable and the window options, but does not disclose other behaviors such as rate limits or authentication requirements, which are not covered by annotations.

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 concise sentences that front-load the tool's purpose and output contents, followed by a practical source for the required parameter. No redundant or wasted language.

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 a simple read-only tool with no output schema, the description thoroughly covers purpose, inputs, outputs (visits, totals, averages, first/last, benchmark), the null case, and how to obtain the required ID. It also mentions window options. This is sufficient for an agent to invoke it correctly.

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 only 50% (merchantId lacks description). The description compensates by telling users exactly where to find merchantId ('Get merchantId from search_transactions or get_top_merchants'), and it restates the window options. It does not add the default window value, but that is already in the 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 uses a specific verb-phrase 'Spending profile for one merchant over a window' and enumerates concrete outputs (visits, totals, averages, first/last visit, benchmark), clearly distinguishing it from sibling tools that cover multiple merchants or general spending breakdowns.

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?

It provides clear context that this tool is for a single merchant's spending profile and implies prerequisites by directing users to obtain merchantId from search_transactions or get_top_merchants. However, it does not explicitly contrast with alternative tools like get_spending_breakdown or aggregate_transactions, so it stops short of full when/when-not guidance.

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