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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral detail beyond annotations: it explains error behavior for nonexistent ids and the meaning of null/0 values in payout fields. This is useful context for interpreting results.

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?

The description is longer than minimal but is front-loaded with the core purpose and use condition, then progressively adds payout term details and examples. Each sentence contributes useful usage or interpretation information, though some payout-field explanation may overlap with the output schema.

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-parameter read-only tool with an output schema, the description covers the parameter source, when to use versus alternatives, error behavior, and the semantics of the returned payout fields. This is sufficient for an agent to select and invoke the tool correctly without missing key context.

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 schema already explains that portal_id is the numeric id from an earlier get_portals or get_portals_by_name result. The description largely repeats this rather than adding new meaning, so it meets the baseline but does not exceed it.

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?

The description states a specific verb ('Returns'), a specific resource ('one cashback portal by its numeric id'), and the included payout terms. It also explicitly names the sibling tools get_portals and get_portals_by_name, making it clear how this tool differs from them.

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 explicit guidance: use it only when the id is already known, and call get_portals_by_name instead when the user names a portal. It also notes that an error is returned when the id does not exist, which helps the agent decide when this tool is appropriate.

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