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

While annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, the description adds valuable behavioral specifics: pricing is quoted before work, processing is sequential and order-preserving, partial failures use safe error codes. These details go well beyond the annotation hints and inform the agent of important execution semantics.

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 three concise sentences, front-loaded with the core purpose, then pricing, then execution behavior. Every sentence contributes unique, non-redundant information without fluff, achieving high clarity in minimal space.

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 batch status tool with a rich input schema and an output schema available, the description covers all necessary aspects: the action, the input constraints (public, 1-5, distinct), the cost model, execution order, and error handling. It does not explain return values, but the output schema handles that, so completeness is strong.

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?

The schema covers both parameters fully (urls and fresh), so the baseline is 3. However, the description adds extra meaning not present in the schema: the pricing formula (per-URL unit price multiplied by URL count) and the processing order guarantee, which relate to the urls parameter's behavior. This supplemental context justifies a 4.

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 opens with 'Check HTTP status for one to five distinct public URLs,' using a specific verb and resource while clearly distinguishing itself from the sibling web.url.status tool by highlighting the batch capability. It also imposes clear scope (1-5 URLs) and eligibility (public, distinct), making the purpose immediately unambiguous.

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 provides clear context for when to use the tool: when checking 1-5 public URLs and when a quote is needed. It states constraints (public, sequential, bounded) but does not explicitly name alternative tools or state when not to use it (e.g., for a single URL, prefer web.url.status, or for content inspection use other tools). This is clear context but lacks explicit exclusions.

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