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

There are no annotations, so the description carries the full burden. It discloses a read-only retrieval behavior and the main output shape (metadata + attachment list), but omits any additional context such as auth expectations, error behavior, or whether attachments are metadata-only references.

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 a single compact sentence with no filler and it front-loads the core action and resource. It communicates the tool's purpose in the least possible words without being a tautology.

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?

With no output schema and no annotations, the description leaves the agent to infer the full return structure and the relationship between the two required parameters. The tool is simple, but explicitly stating that attachments are returned as a metadata list rather than content would disambiguate it from inbox_attachment_get.

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 0%, and the description does not define inboxId or messageId beyond the tool name. The parameter names are self-explanatory, but the description adds no semantic value over the schema and fails to compensate for the missing parameter documentation.

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 uses a specific verb ('Get') and a specific resource ('message metadata and attachment list'), which clearly indicates the tool returns metadata rather than raw message content or a single attachment. It doesn't explicitly name sibling alternatives, but the scope is concrete enough to infer its role.

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?

No explicit guidance is given on when to use this tool versus inbox_message_raw, inbox_attachment_get, or inbox_messages_list. The intended use is only implied by the verb and resource, so the agent must infer when it should be selected over nearby siblings.

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