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

With no annotations, the description carries the burden of behavioral disclosure. It discloses the HTTP method (HEAD) and that it returns only status, but it omits details like redirect handling, timeouts, error behavior, or privacy implications. It also does not clarify that the tool handles multiple input types (e.g., city, json, path) beyond URLs, which is a notable gap.

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 concise sentence that front-loads the primary action and output. There is zero wasted wording, and it conveys the core functionality 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?

The tool has 9 parameters covering diverse inputs (URL, city, JSON, path, timezone, etc.), yet the description only addresses the URL case. It does not explain the tool's broader applicability or how different parameters are handled (e.g., which are checked vs. discarded). Given the complexity and lack of annotations, this is insufficient for an agent to understand full capabilities.

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 100%, so the schema already documents all 9 parameters thoroughly. The description adds no additional parameter context; it only mentions the URL case, which is consistent with the schema but does not compensate for the tool's multi-parameter nature. Baseline 3 is appropriate since the schema handles semantics.

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 clearly states a specific verb ('HEAD') and resource ('public URL') and specifies the output is 'status only.' It distinguishes the tool from siblings that fetch full content (web-fetch) or check availability (browser-url-ok), though it doesn't explicitly name alternatives. It avoids tautology.

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 implies usage when only an HTTP status is needed, but it does not state when to avoid this tool or point to specific alternatives. Given the large sibling set, more explicit routing guidance would be helpful, but the core use case is evident.

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