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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so safety is covered. The description adds no behavioral context beyond the name — no mention of tag validation, error behavior, or what the generated link looks like; it does not contradict the annotations, but contributes nothing extra.

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?

A single front-loaded sentence with no waste, describing the core action immediately. It is arguably too terse to carry usage guidance, but on pure conciseness it is efficient.

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 a full output schema, comprehensive annotations, and 100% parameter coverage, the remaining burden on the description is small; it states the action and the input domain. Only the lack of usage routing and URL/tag validity expectations keeps it from a 5.

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 all three parameters (url, tag, program with its 'amazon'/custom-query-parameter semantics and default) are already documented. The description adds no parameter meaning beyond the schema, which is the baseline-3 case.

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?

Specific verb+resource: 'Build an affiliate tracking link for a product URL' clearly states what is produced. It does not, however, distinguish itself from the sibling check_price or explain how the link differs from a plain URL.

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 gives no when-to-use guidance, no prerequisites (e.g., that a valid affiliate tag is required), and never mentions the sibling check_price or any alternative. Usage must be inferred entirely from the name.

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