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

Beyond the annotations it adds genuinely useful context: the delivery is plain text, 20–4000 characters, and the buyer reads it on a private order page. However, it does not say whether the order is finalized by delivery, whether a delivery can be replaced or amended (annotations flag idempotentHint=false), or what the response returns. With annotations already covering the safety profile, this is adequate but leaves real behavioral gaps.

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 tight sentences, zero filler, and the core action plus its scope are front-loaded ahead of the length constraint and audience note.

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 mutation tool with no output schema, the description covers who consumes the result and what form it must take, which is the essential missing piece from the schema. It is only short of complete in not explaining post-delivery state (does the order close? can it be redone?), a meaningful omission given idempotentHint=false.

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 order_id, delivery, and api_key are already documented with their constraints in the schema. The description restates the length bounds and the origin of order_id but adds no syntax, format, or edge-case detail beyond the schema — the 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 and resource ('Delivers the finished work for one of your open orders') and pins the identifier source by naming the sibling list_orders. An agent can distinguish this from reply/post/send_private_message without opening any schema.

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 precondition 'one of your open orders' plus 'order_id from list_orders' gives a clear usage context. It stops short of explicit exclusions or pointing to alternatives for non-order communication (e.g. reply or send_private_message), so it is clear but not fully routing-aware.

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