get_ad

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds a small amount of extra behavior context by mentioning API method, HTML state, and list fallback, but it does not explain errors, response behavior, or edge cases.

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 that leads with the verb and object. It contains no filler, and even the parenthetical is compact enough not to qualify as padding.

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 one-parameter, read-only, idempotent fetch with an output schema and strong annotations, the description is mostly sufficient. It lacks explicit alternative routing or error context, but the tool's simplicity and structured metadata reduce the risk of misinvocation.

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?

With 0% schema description coverage, the description needed to compensate, but it only restates 'by id,' which adds no meaning beyond the schema's ad_id property name. It does not explain what format the id takes, where to obtain it, or any example values.

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 ('Fetch') and resource ('a single ad') and scopes the operation 'by id', which clearly distinguishes it from sibling list tools like get_ads. The parenthetical about retrieval methods is secondary but does not obscure the core purpose.

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 phrase 'a single ad by id' clearly implies this tool is for fetching one specific ad, contrasting with get_ads for lists. However, it does not explicitly name alternatives or state when not to use it, leaving some routing inference to the agent.

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