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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that – the output is 'cleaned, encoded,' and it will surface tagging errors – but says nothing about what invalid input does or how errors are reported.

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?

One sentence of substance, front-loaded with the core action, followed by a short pointer to the fuller version. Every sentence earns its place, though the external link is mildly promotional rather than operational.

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?

The tool is simple with full schema coverage, and the description does note that it returns a URL and flags errors, which partly substitutes for the missing output schema. However, it doesn't describe the shape of the validation warnings or whether generation can fail, leaving a modest gap.

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 100%, so the schema already documents all six parameters with their UTM mappings and examples. The description only restates the parameter names, adding no format or constraint detail beyond the schema. Baseline 3 is correct.

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 (generate) and resource (cleaned, encoded UTM-tagged URL) plus the secondary function (flag common tagging errors). It's clear what the tool does, though it never names or distinguishes itself from any sibling – a gap that's minor here since no sibling appears to do the same job.

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?

There is no when-to-use, when-not-to-use, or alternative guidance. The purpose implies the use case, but an agent gets no help deciding whether to call this versus, say, landing_page_vs_ad_match_quality_auditor for a link-quality question.

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