agent-tool

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

With no annotations provided, the description carries the full burden and excels by disclosing: security features (SSRF protection, ECH/DoH defaults), network capabilities (HTTP/SOCKS5 proxy support), and operational limits (100MB default/2GB hard limit). No contradictions with annotations exist.

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?

Every sentence earns its place: purpose (sentence 1), capability (sentence 2), sibling differentiation (sentence 3), security features (sentences 4-6), and limits (sentence 7). No redundancy despite the rich information density.

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 9 parameters, no annotations, and no output schema, the description provides excellent behavioral context (security, limits, proxies). It could be elevated to a 5 by briefly mentioning error conditions or return behavior, but it is substantially complete for tool selection.

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 description coverage is 100%, so the schema fully documents all 9 parameters. The description references 'max_size_mb' explicitly and alludes to ECH/DoH features (matching the no_ech/no_doh flags), but with complete schema coverage, the baseline score of 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 opens with a precise action ('Download a file from a URL') and outcome ('save it to disk'). It distinguishes itself from the sibling 'webfetch' tool explicitly, clarifying that this tool is for file persistence while webfetch is for reading web content.

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?

Explicitly states the alternative tool with specific condition: 'For reading web page content as text, use the webfetch tool.' This provides clear when-not-to-use guidance, effectively differentiating from the sibling 'webfetch' and 'httpreq' tools.

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