mail_set_read

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

Annotations declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the mutation-but-not-destructive profile is already conveyed. The description adds only that the target is a single message and that the state toggles both directions, without covering permissions, side effects, or return behavior.

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?

A single short sentence with the verb first and zero filler; every word earns its place and nothing is buried.

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 simple state-toggle tool with no output schema, the description is minimally sufficient to call it correctly. It omits any mention of permission requirements, whether the change is idempotent, and error behavior on an unknown message_id, which a mutation tool would ideally clarify.

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%, so the schema names (message_id, is_read) carry no semantics on their own. The description hints at both: 'one message' maps to the identifier and 'read or unread' maps to the boolean, but it adds no format, accepted values, or ID-source detail.

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 ('Mark') and resource ('one message') with the resulting state (read or unread), so the operation is immediately understandable. It does not, however, distinguish itself from siblings like mail_read or mail_move, leaving the agent to infer the boundary.

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 use this versus mail_read, mail_move, or other mail tools, and no prerequisites or conditions are given. Usage is only implied by the name and the 'read or unread' phrasing.

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