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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds useful behavioral context beyond that: it specifies the exact contents of the returned record and the notable behavior that 'the top result is the exact id match,' which helps agents interpret potentially ranked results.

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?

Three sentences with no filler: the first states purpose and return contents, the second gives the critical usage instruction, and the third clarifies result ordering. Every sentence earns its place and the most important information is front-loaded.

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 lookup with one required parameter, the description covers what is returned, when to call it, and how to interpret the top result. It does not mention error behavior for an unknown serviceId, and there is no output schema, but the listed return fields largely compensate for that gap.

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 the serviceId parameter is already documented as coming from edge_search_services or a bundle's sample.serviceId. The description only says 'by its id,' adding no semantic information beyond the schema, so the baseline score of 3 is appropriate.

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 states a specific verb and resource: 'Look up one service by its id and return its full public record.' It enumerates the exact returned fields and explicitly distinguishes this single-record lookup from a search operation, making the tool's purpose immediately clear and separable from siblings like edge_search_services.

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 explicit usage context: 'Call this before purchasing so the price and freshness are known rather than assumed.' It does not name alternative tools or state when not to use it, but the pre-purchase instruction plus the id-based lookup clearly implies when this tool is appropriate.

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