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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds no extra transparency about side effects, errors, or edge cases, so it meets the baseline given the annotations.

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 short and to the point, but it contains redundancy with the 'Guidance:' line repeating the same information. This minor repetition prevents a perfect score.

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?

The description does not mention what happens if the promocode does not exist, whether it returns a specific schema, or how it fits into the broader shop context. It is minimally complete but lacks helpful context that could guide an agent.

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 parameter promocode_id has a clear description in the schema ('Unique ID of the promocode'), and the tool description reinforces its role. Since schema coverage is 100%, this is above baseline.

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 clearly states that the tool returns details of a single promocode identified by its ID, making its purpose distinct from list and mutation tools for other entities.

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 for retrieving a single promocode by ID but does not explicitly guide when to prefer this over other promocode-related tools (e.g., shop_list_promocodes_*) or how it differs from them.

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