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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond the annotations: these tokens are closed-loop, non-cash, non-transferable, and the issuer is named in the answer.

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?

Three sentences with no filler. The core action is front-loaded, the input is stated in the second sentence, and the final sentence adds an important restriction without bloating the description.

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-only lookup tool with strong annotations and no output schema, the description is complete enough. It explains what is returned ('what is left'), the token scope, and that the issuing business appears in the answer.

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%, with the 'code' parameter already explained via an example ('ABCD-2345-PQRS'). The description only restates that the tool takes 'the code printed on the card,' adding minimal semantic value beyond the schema.

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 ('Return what is left') on a specific resource ('closed-loop token issued by a business through Orbylon') and enumerates the token types it covers: gift card, prepaid hours, membership, or points balance. This clearly distinguishes it from siblings like lookup_business or place_order.

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 makes the triggering condition clear: use this when you have a code printed on a card and need to know its remaining value. It does not explicitly list when-not-to-use scenarios or name alternatives, but the resource and purpose are unambiguous enough for an agent to select it correctly.

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