mark_email_read

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

Annotations are absent, so the description must carry the full behavioral burden. It only states the mutation ('Mark') without disclosing side effects, prerequisites, default behavior when isRead is omitted, or the response behavior. This is thinner than the update_drive calibration example.

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 short sentence with no filler or redundant wording. It is front-loaded and efficient, though its brevity borders on under-specification rather than being a complete description.

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 mutation tool with no annotations and no output schema, the description is not complete enough. It does not clarify what happens if isRead is omitted, how the email is identified, or what the result of the operation is. Given the simple schema, it is adequate only at a surface level.

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 33% (mailbox only), so the description must compensate for the undocumented emailId and isRead parameters. The phrase 'read or unread' partially maps to isRead, but emailId remains unexplained, and no parameter formats or defaults are provided.

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 ('Mark') and a clear resource ('an email') and even covers both directions ('read or unread'). It is unambiguous at a basic level, though it does not explicitly distinguish itself from sibling tools beyond the action itself.

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 guidance about when to use this tool versus alternatives like triage_email, get_unread_emails, or move_email. An agent is left to infer that this is the correct tool for changing read state.

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