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

With no annotations, the description must carry the full behavioral burden. It does add genuinely useful non-schema context — pricing (5000 atomic USDC) and a payment-authorization prerequisite — plus the negative scope of not testing links or tracking visits. However, it omits behavior for edge cases such as URLs that already contain UTM parameters and what the tool returns.

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?

Three short sentences, front-loaded with the core action, then scope exclusions and payment terms. Every sentence carries information and there is no filler, though the payment sentence is a bit abrupt in placement.

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?

There are no annotations, no output schema, and zero schema description coverage, so the description should do more. It covers purpose, scope, and cost, but never states the return value (presumably the rewritten URL), which is a real gap when no output schema exists.

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 for four undocumented parameters. It names source, medium, and campaign but adds no format, encoding, or overwrite semantics, and never mentions the url parameter; it essentially restates the parameter names without extra meaning.

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?

States a specific verb (add) and resource (UTM parameters to an HTTP(S) URL), which is concrete and unambiguous. It does not reference the related sibling url_normalize, so an agent gets no explicit differentiation from the closest alternative, keeping it below a 5.

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?

"Does not test links or track visits" scopes the tool negatively and implies when it is appropriate, but there is no positive when-to-use statement and no alternative named. Usage is inferable but not spelled out.

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