mhlb_get_coupon

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

Annotations already provide readOnlyHint=true, so the read-only nature is covered. The description adds 'if any', indicating the coupon may be absent, which is a behavioral nuance beyond the annotation. However, it does not specify what happens when no coupon exists (null, empty, etc.), and it doesn't disclose any other behavioral traits. The addition is modest.

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 a single concise sentence that front-loads the verb 'Get' and specifies the resource and scope. There is no redundant wording, and every word contributes meaning. It is appropriately minimal for a zero-parameter read tool.

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 simple read-only getter with no output schema, the description is largely sufficient. It states what is returned (the coupon) and that it may be absent. It doesn't detail the coupon structure, but that is not necessary for invoking the tool correctly. The annotations cover safety, and the sibling tools provide context. A small gap is the lack of explicit return-type clarification, but overall it is complete enough.

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?

The tool has zero parameters, so the baseline is 4 per the rubric. There is no parameter information to add beyond what the schema provides, and the description correctly avoids inventing any. This is a non-issue.

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 uses a specific verb 'Get' and identifies the resource 'coupon' along with scope 'currently applied to the account, if any'. It clearly distinguishes from sibling mutators mhlb_apply_coupon and mhlb_remove_coupon, so an agent can immediately tell this is a read-only retrieval.

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 usage as a getter, but does not explicitly state when to use it versus alternatives like apply/remove. There is no mention of 'use this to check the current coupon before applying' or any exclusion. The context is clear from the name and sibling list, but the guidance is implied rather than explicit.

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