web_fetch

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

With no annotations present, the description carries the transparency burden. It discloses the HTTP method and the crucial 'offline stub by default' behavior, which is valuable caveat. However, it does not detail response handling, error behavior, or potential side effects, leaving some gaps.

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 a single sentence, front-loaded with the primary action and resource. Every word adds value, including the important 'offline stub' caveat. It is appropriately concise with no filler.

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 simple one-parameter tool with an output schema, the description covers the essential purpose and a key behavioral trait. However, it lacks usage guidance and alternative differentiation, and the absence of annotations increases the need for more contextual details about expected 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?

The schema provides no description for the 'url' parameter (coverage 0%), so the description must compensate. It only says 'Fetch a URL,' which essentially restates the parameter name and adds no information about URL format, encoding, or expected constraints.

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 states a clear action ('Fetch a URL') with a specified resource and method ('over HTTP GET'), which distinguishes it from sibling tools like calculator and file_read. The additional caveat 'offline stub by default' adds useful specificity about the tool's behavior.

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?

There is no guidance on when to use this tool versus alternatives, no prerequisites, and no exclusions or limitations beyond the stub note. It only implies usage for fetching URLs, but does not offer explicit contextual direction.

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