check_url_status

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

With no annotations, the description carries the full burden and does substantial work: it discloses the SSRF guard, the globally-routable-only restriction, the five-redirect cap, HEAD-only requests, and that nothing is downloaded or submitted. It does not cover timeouts, rate limits, or authentication requirements, which leaves room above a 4.

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?

Front-loaded with the purpose, then grouped into guard behavior, request behavior, and error semantics. Every sentence contributes a distinct operational fact with no repetition.

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 tool with an output schema, this covers nearly everything an agent needs, including the crucial clarification that `reachable: false` is a successful check result rather than a failure. The remaining gap is URL format and timeout behavior.

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% for the single `url` parameter, so the description must compensate. It adds the important constraint that only globally routable addresses may be fetched, but never states whether a scheme is required or which schemes are accepted, leaving the most basic input-format question unanswered.

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 whether a URL is reachable and what status it returns. No sibling overlaps this capability (the siblings are password, expense, currency, repo, and time tools), so there is no ambiguity to resolve.

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?

Usage is only implied: an agent can infer this is for verifying URL reachability, but there is no explicit statement of when to prefer it over another approach and no exclusions. There are no close alternatives among the siblings, which softens the gap but does not eliminate it.

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