web_fetch

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

With no annotations, the description carries the full burden and does well: it discloses URL format requirements, automatic HTTP->HTTPS upgrade, format options with default, response size limit (5MB), and timeout (120s). This goes beyond the minimal and provides useful operational expectations.

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 well-structured with a clear main statement followed by usage notes. It front-loads the core purpose and each bullet adds value without redundant repetition, making it appropriately sized 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?

Despite lacking an output schema, the description covers input requirements, behavior, format options, size/timeout limits, and relationship to sibling tools. This is a self-sufficient explanation for how to invoke web_fetch 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 coverage is 100% and already includes URL, format enum, and timeout range. The description adds extra meaning by explaining the URL must be fully-formed and valid, and that HTTP URLs are upgraded to HTTPS, which supplements the schema.

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 opens with a specific verb+resource: 'Fetches content from a specified URL and converts it to readable format.' It clearly distinguishes itself from searching and sibling tools like web_search by stating 'not for searching.'

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?

Explicit guidance is provided: 'Use this when you have a specific URL to retrieve (not for searching)' and 'Use web_search first to find URLs, then use this tool to fetch their content.' It also mentions preferring Context7 for documentation, giving clear when-to-use and alternative guidance.

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