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

The description adds substantial behavior beyond the annotations: the enquiry is saved to the buyer's inbox, the seller is notified, there is a per-buyer-per-listing daily cap of 2, and the required OAuth scope is named. It also clarifies the scope-name ambiguity with seller-side replies. These are exactly the side-effect and context details an agent needs.

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 compact and front-loaded: action first, then key side effects, capabilit constraints, and a useful example. Every sentence carries distinct information and nothing feels redundant or padded.

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 two-parameter tool with an output schema and annotations, the description is complete: it states the action, destination, notification side effect, spam limitation, authorization requirement, and where to read the reply. No critical operational detail is missing.

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 schema already covers both parameters with clear descriptions, so the baseline is 3. The description adds value with a concrete natural-language example that shows how a buyer request maps to listingId and message content, including negotiation details like price and collection location. This extra example meaningfully helps an agent construct the call.

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 opens with a specific verb and resource: 'Send an enquiry to a Cyclesite seller on the buyer's behalf.' It clearly distinguishes this buyer-initiated action from sibling tools like respond_to_enquiry and get_my_messages, and the example reinforces the intended use.

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 clear context for when to use the tool and even routes follow-up behavior: 'Read the seller's reply with get_my_messages.' It also notes the OAuth scope prerequisite and the daily cap. It could more explicitly contrast with respond_to_enquiry, but the sibling differentiation is implied well enough.

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