Fetch URL

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

The description adds behavioral context beyond annotations, notably the 64 KB inline response cap with a [TRUNCATED] marker. Annotations declare readOnlyHint true and destructiveHint false, which are consistent. The description does not cover authentication or rate limits, but the added detail about truncation is valuable.

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 two sentences with no extraneous words, front-loading the core action and providing key behavioral constraints immediately.

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 five parameters (one required) and no output schema, the description covers the main behavioral aspects: inline vs file output and the 64 KB limit. It lacks details on error handling, timeouts, or authentication, but for a simple fetch tool, it is sufficiently complete.

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%, so the baseline is 3. The description reiterates the outputFile parameter's purpose and clarifies the default inline behavior, but adds minimal new meaning beyond the schema descriptions.

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 sends an HTTP/HTTPS request from the router using /tool/fetch, which is a specific verb and resource. It distinguishes itself from sibling tools like ping, traceroute, and bandwidth_test by being the only tool for fetching URLs.

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 guidance on when to use the outputFile parameter to save to the router filesystem instead of returning inline. However, it does not explicitly state when not to use this tool or reference alternative tools for similar tasks, but the context is clear enough.

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