mark_as_unread

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

No annotations are provided. The description only states the action 'mark emails as unread' and an unrelated fact about UIDs being permanent. It fails to disclose effects like flag state changes, reversibility, or required permissions.

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 two short sentences, front-loads the action, and contains no filler. The note about UIDs is brief and relevant.

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 mutation tool with well-described parameters, the description is minimally viable. However, it lacks usage context and any mention of interactions with other email operations. Given the absence of annotations and output schema, it leaves some gaps but does not feel severely incomplete.

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 covers both parameters with descriptions. The description adds value by explaining that UIDs are permanent identifiers, which clarifies why they are used as the primary key. This goes beyond the schema's simple 'Array of UIDs to mark as unread'.

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 the specific verb 'Mark' with resource 'emails' and indicates the method 'using UIDs'. It clearly conveys the action of setting emails to unread, which inherently distinguishes it from the sibling mark_as_read. However, it doesn't explicitly name alternatives, so slightly below perfection.

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 on when to use this over mark_as_read, archive, or other actions. The description lacks context about use cases or prerequisites, such as requiring UIDs from a prior list operation.

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