Url Content Type

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

Annotations already indicate readOnlyHint, idempotentHint, and destructiveHint=false. The description adds that no JavaScript is executed, no access controls bypassed, and that caching is used (fresh=false). It also notes that private/internal URLs are rejected, providing safety context beyond annotations.

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 three concise sentences with no fluff. It front-loads the purpose and immediately provides usage constraints. Every sentence adds necessary information.

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?

With two parameters, full annotations, and an output schema present, the description covers all necessary aspects: input constraints, caching semantics, and boundaries (public only, no JS). The output schema handles return structure, so no further details needed.

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 has 100% coverage with descriptions for both parameters. The description adds significant value: for url it details the rejection of SSRF-sensitive destinations, and for fresh it explains caching behavior and cost implications, going well beyond 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 clearly states the tool classifies MIME type, charset, and bounded content length. It specifies the resource (public HTTP(S) URLs) and the action (classify), distinguishing it from sibling tools that handle other aspects like headers, status, or extraction.

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 explicitly restricts usage to public HTTP(S) resources and clarifies it does not execute JavaScript or bypass access controls. It also provides guidance on the fresh parameter for cache reuse. While it does not name alternative tools, the context of sibling tools makes the purpose clear.

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