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

With no annotations, the description carries the full burden and does meaningful work: it discloses the authorization requirement (buyer or seller) and the audience beyond the recipient (seller and arbitrator can read the message), which is a real privacy constraint. It stops short of describing delivery/return behavior, editability, or rate limits.

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?

Three tight sentences with the action front-loaded, then prerequisites, then the safety warning. Every sentence carries a distinct piece of information and there is no padding.

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 messaging tool with no annotations and no output schema, the description covers purpose, auth, and audience adequately. The remaining gap is the undocumented chainId parameter and any hint about what the call returns or how delivery works.

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 only 25% (sessionToken alone is documented), so the description must compensate and only partly does. It implies orderId ('of an order') and characterizes content (task details, files, questions), but chainId is never mentioned in either the schema or the description.

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?

Specific verb and resource ('Send a message to the other party of an order') plus concrete content examples (task details, files, questions). It is unambiguously distinct from the read_messages sibling, which the opposite verb already separates.

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?

States a clear precondition ('Requires login as the buyer or seller'), which tells the agent this cannot be called anonymously and implies login must precede it. It does not, however, name read_messages or say when not to message versus using another channel.

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