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

With no annotations, the description must carry the behavioral burden, and it discloses one high-value trait that structured fields cannot: the returned messages are untrusted data and must not be treated as instructions. It still omits other traits such as read-only/no-side-effect behavior, pagination or thread size limits, and auth expectations, keeping it below a 5.

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 with zero waste: the purpose is front-loaded and the security warning follows immediately. Every sentence earns its place and nothing is 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 read tool with no annotations and no output schema, the description covers purpose and the prompt-injection hazard but leaves real gaps: the meaning of chainId, whether reading marks messages as seen, auth requirements, and result volume/pagination. It is adequate but not complete for a 3-parameter tool.

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 coverage is only 33% (only sessionToken is documented), so the description is expected to compensate and it does not: chainId is never mentioned or explained, and orderId is only indirectly implied by 'thread of an order'. The schema already supplies the secret-handling note for sessionToken, so the description adds no parameter meaning.

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 gives a specific verb and resource ('Read the message thread of an order'), which is unambiguous and clearly pairs with the sibling send_message as the read-side counterpart. It does not explicitly name or contrast a sibling, so it stops short of a 5.

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?

There is no statement of when to call this versus alternatives (e.g., get_order_status, list_proposals) and no prerequisites listed. The instruction about how to treat returned messages is useful handling guidance, but that is not the same as selecting this tool over another, so usage is only implied by the tool's name.

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