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

With no annotations, the description carries the full burden. It usefully discloses the cost (2 credits per call) and what is returned, but omits auth requirements, timeouts, redirect-following depth, or rate limits that matter for an unattended checker.

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?

One compact sentence-cluster, front-loaded with the action and results, then the use case, then cost. Every clause earns its place with no filler.

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 single-parameter read tool with no output schema or annotations, the description covers purpose, return contents, quantity limit, and cost. It only lacks an explicit read-only/permission statement, a minor 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 coverage is 0%, but the single parameter is a self-evident array of URI strings. The description adds that up to 20 URLs are checked and what each yields, though "up to 20" duplicates the schema's maxItems and no format details are added.

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?

States a specific verb and resource (check URLs) and enumerates exactly what is returned: HTTP status, final URL after redirects, content type. It does not name or differentiate itself from relevant siblings like redirect_chain, phishing_url_check, or security_headers, so an agent must infer the distinction.

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?

"Good for finding broken links" implies the use case but offers no explicit when-to-use/when-not or routing to alternatives (e.g. redirect_chain for deeper redirect inspection, phishing_url_check for safety). Usage is implied rather than stated.

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