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

readOnlyHint=true already declares a safe read, so the bar is lower; the description adds genuine value by disclosing what the payload contains (reward rules, totals), which matters because there is no output schema. It does not cover pagination behavior beyond what the schema states, hence not a 5.

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 core purpose front-loaded and the returned fields grouped compactly. The trailing endpoint reference is slightly redundant, keeping it just short of a 5.

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 no output schema, the description usefully compensates by naming the returned reward-rule and total fields, and both optional parameters are covered by the schema. Nothing critical for calling the tool correctly is missing.

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?

With 100% schema description coverage, page and limit are already fully documented in the schema. The description adds no syntax or formatting detail for these parameters, so the baseline 3 applies.

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 and resource ('List the affiliate program's campaigns') and enriches it by enumerating the reward rules and totals returned. This clearly separates it from rewardful_get_campaign by plurality/scope, though it never explicitly names that sibling as the alternative.

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 listing intent is implied and the endpoint (GET /v1/campaigns) confirms a read-all operation, but there is no explicit when-to-use guidance or routing away from rewardful_get_campaign for a single campaign. Adequate but with a clear gap.

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