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

Goes well beyond the annotations: the campaign is active immediately, is publicly listed in Discovery unless isPublic is false, plan limits apply, and Pro plan plus live keys are required. It also discloses the return payload (campaign plus joinUrl) and the sharing semantics of that join link — exactly the mutation side effects an agent needs.

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?

Front-loads purpose, then the return value, the confirmation rule, the side effects, and the plan prerequisites in descending order of importance. Five sentences, each carrying a distinct fact; nothing is repeated from the name or title.

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 13-parameter, non-idempotent, world-visible write operation with no output schema, the description covers prerequisites, side effects, quota, user confirmation, and the return shape. There is no output schema, yet the agent still learns the response includes the campaign and joinUrl.

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 coverage is 100%, so the schema already carries full parameter documentation and the baseline is 3. The description adds only light meaning beyond that — the behavioral consequence of isPublic and the fact that recurring commissions pay on renewals — without adding format, range, or interaction detail the schema lacks.

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?

Opens with a specific verb and resource ('Create an affiliate campaign') and immediately qualifies the resource in business terms — what affiliates earn per sale and where links send people — so the agent knows exactly what the object is. It is clearly distinguishable from update_campaign, get_campaign, and list_campaigns by verb.

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?

Gives concrete pre-call guidance ('Confirm the commission with the user before calling') plus prerequisites ('Requires Pro plan or higher; live keys only') and a quota constraint ('The plan's campaign limit applies'). It doesn't name alternatives, but the create/read/update sibling split is unambiguous from the name alone.

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