mark_emails

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

There are no annotations, so the description carries the full burden of disclosing behavior. It clearly states the modifications being made and clarifies that 'flagged' means 'starred'. However, it does not mention permissions, reversibility, partial failures, or how invalid UIDs are handled, which are relevant for a mutation tool.

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, front-loaded sentence that lists all supported actions with no filler or redundancy. Every word contributes to the understanding of the tool's purpose.

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 low-complexity tool with fully documented parameters and an enumerated action set, the description is nearly sufficient. It lacks an explicit note about return values or when to prefer it over a sibling, but an agent can correctly determine how to invoke it from the schema and description together.

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?

The input schema provides 100% parameter coverage with clear descriptions for 'uids', 'action', and 'folder'. The description adds minimal extra meaning, mainly the clarification that flagged equals starred and that multiple emails can be processed at once. This matches the baseline for high schema coverage.

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 ('emails'), then enumerates the exact state changes: read, unread, flagged (starred), or unflagged. This makes it easy to distinguish from sibling tools like move_emails, delete_emails, or get_recent_emails.

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 conditions for use or alternatives are provided. The intended use is implied by the action and resource, so an agent can infer it is for updating email read/flag state rather than searching, moving, or deleting. However, the lack of explicit when-to-use or when-not-to-use guidance keeps it below a 4.

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