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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds that the resource is machine-readable and includes feed endpoints, which is useful, but does not disclose behavior such as what happens with an unknown merchant or what the feed endpoints represent.

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 a single front-loaded sentence with no wasted words. It states the operation and resource immediately.

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?

An output schema exists, so return-value details need not be explained, and the annotations cover safety. Still, for an open-world lookup tool with one opaque required parameter, the description should clarify the merchant identifier format and what 'feed endpoints' means in context.

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% for the single 'merchant' parameter, and the description does not explain whether it expects a merchant ID, domain, name, or other identifier. With no compensation for the schema's silence, an agent lacks enough information to supply the parameter correctly.

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 names a specific verb (Read) and resource (a merchant's machine-readable agent-commerce profile and feed endpoints), which is clear enough for an agent to understand the operation. However, it does not differentiate this tool from siblings like merchant_diagnostic or merchant_offer_search, so it falls short of a 5.

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 gives no guidance on when to use this tool versus alternatives such as merchant_diagnostic or merchant_offer_search. It implies a lookup use case but leaves all routing decisions to inference.

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