validate_url

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

No annotations are provided, so the description carries full burden. It discloses the parsing standard (WHATWG), TLD check via IANA suffix list, and lists the return fields (protocol, hostname, port, path, TLD known). This provides sufficient behavioral insight.

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 two sentences, front-loaded with the key action ('USE THIS to verify...'), and concise. Every sentence adds value, no wasted words.

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 a single parameter and no output schema, the description is fairly complete: it explains what the tool does, how it validates, and what it returns. It lacks discussion of error handling or edge cases, but for a simple validation tool this is acceptable.

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%, with the schema already describing the 'url' parameter. The description adds no extra parameter-level meaning beyond the schema; it explains the validation logic but not parameter specifics. Baseline 3 is appropriate.

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 tool's purpose: to verify a URL before fetching or storing it, using the WHATWG URL standard and checking TLD against IANA suffixes. This is specific and distinct from sibling tools like validate_domain or validate_email.

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 begins with 'USE THIS to verify a URL before fetching or storing it', providing clear usage context. It does not explicitly exclude alternatives, but the sibling context implies each tool has its own validation domain.

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