Fetch a URL

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 that output is truncated to a safe length and that only http/https is permitted, but omits auth requirements, redirect/error behavior, timeouts, and any mention that POST with a body is supported despite the schema allowing it.

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?

Three tight sentences with the core action front-loaded and the constraint (http/https only, truncation) trailing. No filler or redundancy.

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?

With no output schema, the description does explain what is returned (text, truncated), which is the key missing piece. The main residual gap is that POST/body usage is never mentioned even though the schema supports it.

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 already documents url, body, and method (including the GET/POST enum and GET default). The description adds no parameter-level detail beyond the schema, so the baseline of 3 applies.

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 gives a specific verb and resource: 'Fetch the contents of a public http(s) URL and return the response body as text.' This clearly separates it from file-oriented siblings like read_file or list_directory, though it never names an alternative explicitly.

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?

'Useful for reading web pages, JSON APIs, or other public HTTP resources' gives implied usage contexts, but there is no explicit when-to-use vs. when-not-to-use guidance and no reference to sibling tools such as read_file for local content.

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