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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds real value beyond that by disclosing payload contents — the affiliate and the bundled commissions — which is behavioral context the agent cannot get from the annotations. It does not mention pagination or error behavior, but neither is relevant for a single-resource fetch.

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 tightly packed sentences with zero filler; the core action and its return contents come first, with the endpoint reference trailing as a low-cost anchor.

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 one-parameter read tool with no output schema, the description covers the essentials: what is fetched, by what key, and what the response bundles. Only the missing explicit relationship to rewardful_list_payouts keeps it from being fully complete.

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% and the single parameter is fully documented as a UUID in the schema. The description's 'by id' adds no format or constraint detail beyond that, so the schema is doing the heavy lifting — 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 (Fetch) and resource (a single payout by id) and names the sibling dimension that distinguishes it from rewardful_list_payouts — singular vs. collection retrieval. It also names the endpoint for traceability.

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: the phrase 'by id' suggests the caller must already have a payout_id, and the singular framing implies the use case is fetching one known payout. No explicit when-to-use or when-not-to-use against rewardful_list_payouts is stated.

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