fetch_url

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

No annotations provided; description discloses it makes live HTTP requests, returns detailed data, and is free. Lacks disclosure on rate limits, error handling, authentication, or size constraints.

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?

Two sentences, front-loaded with core functionality, no fluff. Every phrase adds value.

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?

Tool is simple and description covers key outputs and cost. Missing details on error behavior and authentication, but acceptable for a straightforward fetch tool.

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 has 0 parameters with 100% coverage; baseline for 0 parameters is 4. Description does not add parameter info but also does not need to since no parameters are defined. However, the open schema (additionalProperties true) may confuse agents expecting a 'url' parameter.

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?

Description clearly states tool fetches a live URL and returns specific data (final URL, status, redirect chain, timing, SEO elements, markdown, HTML). It is distinct from sibling tools which are analytics-focused.

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?

Description implies usage for fetching URLs but does not explicitly mention when to avoid or provide alternatives. However, given no similar sibling tools, the context is clear.

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