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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuine context by enumerating the returned payload (commission, cookie, network, payment model, requirements, sources, verification date, modelled value), which is the main thing the annotations do not convey given there is no output schema.

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, front-loaded with the action and lookup key, with the field list in a compact parenthetical. No wasted words.

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 single-record lookup with only one required param and full annotation coverage, the description supplies what the missing output schema would otherwise provide by listing the returned fields. It stops short of noting not-found behavior or exact response shape, but nothing critical to invoking it correctly is absent.

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 slug parameter is already fully documented in the schema, including the format example 'nom-nom' and its provenance from search_affiliate_programs. The description adds nothing beyond that, matching the baseline 3.

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+resource ('Get the full record for one affiliate program') and the lookup key (slug). It does not explicitly name the sibling it complements, search_affiliate_programs, in the description itself, so an agent must infer the list-vs-single split from the schema text.

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?

Usage is only implied: 'by its slug' signals a single-record lookup, and the schema note references slugs 'as returned by search_affiliate_programs'. There is no explicit when-to-use statement or exclusion against the sibling search/list tools.

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