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

The description adds behavioral context beyond annotations, such as 'Does not execute JavaScript' and mentions cache state and robots policy. It does not contradict annotations.

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 efficiently written in three sentences, front-loading the purpose and key behaviors before parameter-specific advice. No extraneous content.

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?

Given the tool's complexity and the presence of an output schema, the description adequately summarizes key return fields and constraints, though it could mention the output schema's structure briefly.

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 100% schema coverage, the description adds value by reinforcing usage patterns for both 'url' and 'fresh', e.g., 'Pass url as an absolute public HTTP(S) URL' and 'Keep fresh=false to reuse cache; set fresh=true only when a new upstream fetch is required.'

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 the verb 'check' and resource 'public HTTP or HTTPS URL', and lists the returned information (availability, redirects, content type, etc.), distinguishing it from siblings that focus on specific aspects.

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?

It explicitly recommends using this tool 'before expensive browsing or AI processing' and gives practical guidance on the 'fresh' parameter ('Keep fresh=false... set fresh=true only when...'). However, it does not directly compare with sibling tools to help select among them.

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