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

With no annotations, the description carries the full burden and does disclose two useful traits: a required merchant agent key (auth) and a scoping restriction on what is returned. However, it never confirms this is a read-only/non-mutating operation or describes error behavior when a code is invalid or not found.

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 short sentences, front-loaded with the core action and followed by the auth/scope constraint. Nothing is wasted, though it is quite terse given it lacks any output or error context.

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?

No output schema exists, so the description would ideally hint at what the returned status contains or what values are possible. It covers the input/auth surface adequately but leaves the return semantics and failure cases unexplained for a lookup tool.

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%, so both parameters are already fully documented in the schema. The description's 'by code or ID' phrasing merely restates the two schema fields and adds no format or precedence detail beyond them; 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 (Check) and resource (voucher status), and clarifies the two accepted identifiers (code or ID). It is distinguishable from write-oriented siblings like use_voucher or redeem_reward, though it does not explicitly name an 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 description implies the lookup use case but gives no explicit when-to-use vs when-not guidance and never references alternatives such as use_voucher. The scoping note ('only vouchers issued by the key owner's store are returned') adds implied usage context but not routing guidance.

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