web_fetch

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

With no annotations, the description carries the full transparency burden. It usefully discloses that rendered=True drives a headless browser and requires RENDER_ENABLED=true, going beyond the schema. However, it does not explain the default non-rendered behavior, failure modes, or other behavioral constraints.

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?

Two short sentences with the main purpose front-loaded and the optional rendering mode stated compactly. Every sentence earns its place and there is 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 two-parameter fetch tool with an output schema, the description covers the core behavior and the one non-obvious mode. It is slightly incomplete in that it omits explicit sibling routing and default-mode behavior, but it is sufficient for basic invocation.

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 adds real meaning for rendered by explaining the headless-browser behavior and the RENDER_ENABLED requirement, but the url parameter is only implicitly covered by 'Fetch a webpage' and gets no format or constraint detail.

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 specific verb ('Fetch') and resource ('a webpage') and adds the key value extra ('extract its main readable content'), making the core purpose clear. It does not explicitly differentiate from the sibling web_search_and_fetch, which may also involve fetching pages.

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 gives no guidance about when to use this tool instead of web_search or web_search_and_fetch. The rendered=True note is a configuration instruction, not a usage-selection guideline, and no alternatives or exclusions are mentioned.

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