fetch_url

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

No annotations are provided, so the description carries the burden. It discloses the proxy usage and the text/markdown output, but it doesn't explicitly state that the operation is read-only (though implied), nor does it mention any rate limits, authentication requirements, or error behaviors.

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, well-structured sentence that front-loads the action and provides essential context (proxy, output format) without any wasted words.

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 fetch tool, the description is nearly complete: it states the action, output format, and a key contextual detail (proxy). It omits potential error cases or usage restrictions, but these are not critical for the tool's basic function.

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 covers the single parameter 'url' fully (100% description coverage). The description adds the proxy context but doesn't provide additional parameter-level semantics beyond what the schema already states.

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 ('read') and clear resource ('website content as text/markdown'), and distinguishes itself from siblings by mentioning the Cloud Proxy and IP-block avoidance, which makes it clearly a URL-fetching tool rather than a search tool.

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?

The description clearly implies when to use it (reading a web page, especially when IP blocking is a concern via the proxy mention), but it does not explicitly mention alternatives or exclusions. It's clear context without formal exclusions.

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