fetch_url

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

With no annotations provided, the description carries full burden for behavioral disclosure. It hints at security filtering ('after SSRF policy checks') but omits key behaviors: what happens on failure (timeouts, blocked domains), size limits, caching, authentication (public only), response format, or side effects. This is insufficient for a tool that makes network requests.

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, front-loaded sentence with no redundancy. Every word is meaningful. It is optimally concise for the information it conveys.

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 no output schema and minimal schema details, the description should explain return values (e.g., raw content, headers, status), errors, and how SSRF checks affect behavior. It does none of this, leaving critical gaps for an agent to invoke the tool correctly.

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%, so the description must compensate. It does add meaning by specifying that the 'url' must be public and support HTTP/HTTPS, which the schema (just a string) does not indicate. However, it doesn't clarify the required nature or expected format (e.g., must include scheme). The added value is moderate.

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 clearly states the tool's purpose: to fetch a public HTTP(S) URL after SSRF policy checks. The verb 'Fetch' and resource 'URL' are specific, and the description distinguishes it from sibling tools like calculator, read_file, and write_note by targeting external web resources.

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 provides no guidance on when to use this tool versus alternatives (e.g., read_file for local content, calculator for math). It mentions SSRF policy checks but does not explain prerequisites, limitations, or what URLs are allowed. No explicit when/when-not information is given.

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