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

With no annotations, the description carries the burden and discloses meaningful behavior: lower-casing normalization, safe encoding, one URL per source/medium pair, and a per-call cost of 1 credit. It does not cover auth requirements or error behavior, but the operational traits it does expose are genuinely useful.

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 tight sentences with the purpose front-loaded and cost isolated in its own clause. No filler, though the description is short enough that it could have spent a little more on parameter meaning.

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 5-parameter tool with no annotations, no output schema, and 0% schema coverage, the description is only partially complete. It conveys output cardinality and billing but does not explain the key inputs or the resulting URL structure an agent would need to call it confidently.

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, but it only gestures at the channels parameter ('source/medium pair'). The url, campaign, term, and content parameters receive no explanation or format guidance, leaving most of the 5-parameter surface undocumented.

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 (Build) and resource (campaign tracking URLs with UTM parameters), plus output cardinality ('one per source/medium pair'). No sibling tool overlaps with this function, so the purpose is unambiguous.

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 campaign-tracking context implies when the tool applies, but there is no explicit when-to-use/when-not guidance. Since no sibling competes in this space, the omission is low-risk but still leaves usage implicit rather than stated.

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