mail_set_read_status

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

Annotations already indicate idempotentHint=true, implying safe re-calls. The description adds that it can set both read and unread states. However, it does not disclose any behavioral details beyond that, such as response behavior or side effects. With annotations covering idempotency, the description adds minimal value.

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 very short (one sentence), which is concise but lacks necessary details. While brevity is good, the single sentence does not earn its place because it omits critical information. It is appropriately sized for a simple tool but not sufficiently informative.

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 5 parameters (3 required) and no output schema, the description is incomplete. It does not explain how to specify the target message or the meaning of the required 'value' parameter. The agent lacks sufficient information to correctly invoke the tool without additional context.

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%, yet the description provides no explanations for the parameters. For example, the 'value' boolean parameter is not clarified (true for read vs false for unread), and the difference between 'messageId' and 'rfc822MessageId' is not addressed. The description completely fails to add meaning beyond the schema.

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 clearly states the tool's purpose: marking a message as read or unread. It uses a specific verb 'mark' and resource 'message', differentiating it from sibling tools like 'mail_set_flagged' (which sets flagged status) and 'mail_set_flag_color' (which sets flag color).

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 guidance is provided on when to use this tool versus alternatives. It does not mention prerequisites (e.g., message must exist), nor does it explain when not to use it. Siblings like 'mail_get_message' could be used for reading, but no comparison is made.

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