mark_emails_as_unread

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states that emails are marked as unread, but does not disclose whether thread_ids and message_ids can be combined, whether at least one list is required, or what the outcome is if no IDs are supplied. It is not misleading, but it is too thin.

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 concise and has no filler, but it is under-specified. For a tool with three parameters and an unannotated mutation, one short sentence restating the tool name is not appropriately sized; it lacks the structure needed to guide correct invocation.

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?

The presence of an output schema reduces the need to describe return values, but the core call semantics remain incomplete. The description does not clarify the thread-versus-message distinction, the relationship between the optional parameters, or when this tool should be chosen over mark_emails_as_read. An agent would still have to infer important behavior.

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 compensate. It provides no explanation of account_id, thread_ids, or message_ids, and leaves ambiguous whether thread_ids and message_ids are alternatives or can be used together. The verb 'emails' loosely maps to the ID parameters, but the description adds almost no meaningful parameter semantics.

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 operation: mark emails as unread. It names a specific verb and resource, and the 'unread' target distinguishes it implicitly from the sibling mark_emails_as_read. However, it does not mention whether it applies to threads, messages, or both, so it stops short of full precision.

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 such as mark_emails_as_read, list_emails, or move_emails. The description only restates the action and gives no context about prerequisites, when it is appropriate, or when a different tool should be chosen.

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