fetch_url

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

There are no annotations, so the description carries the full burden of behavioral disclosure. It does not mention possible failures (e.g., invalid URLs, network errors, redirects), rate limits, authentication requirements, or the structure/format of the returned content. This is a significant gap for a network-fetching tool.

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 concise sentence, front-loaded with the core action. It is easy to scan and understand the primary purpose. However, the brevity sacrifices important behavioral and usage details, so it is not perfectly complete for the tool's complexity.

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 that there is no output schema and no annotations, the description needs to provide more context about what the agent should expect. It does not describe the return structure, error handling, or what formats 'extractable content' may take. For a simple tool with only two parameters, the description is under-specified and leaves too much to inference.

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 0%, and the description only indirectly references the 'url' parameter ('Fetch a URL') and the 'extract' action ('extract readable content'). It does not explain the two parameter names, the enum choices for 'extract', or the default behavior. The schema provides the default and enum, but the description adds little semantic value beyond what the parameter names imply.

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 uses a specific verb 'Fetch' and clearly identifies the resource ('a URL'), with the added action of extracting readable content. It is distinguishable from sibling tools like 'web_search', which implies a search-based retrieval rather than direct fetch of a specified URL. However, it does not explicitly state what 'readable content' includes, leaving some ambiguity.

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?

No guidance is provided on when to use this tool versus alternatives like web_search or get_context. There are no exclusions, prerequisites, or preferred scenarios. The description simply states the action, leaving the agent to infer when it is appropriate.

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