MCP Email Service

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the action ('Move') but doesn't clarify if this is reversible, what happens if the email is already in trash, or any rate limits or authentication requirements. This leaves significant gaps in understanding the tool's behavior beyond the basic operation.

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, efficient sentence that directly states the tool's purpose without any wasted words. It is appropriately sized and front-loaded, making it easy for an agent to parse quickly, earning the highest score for conciseness.

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?

Given the complexity of a mutation tool (moving emails) with no annotations and no output schema, the description is insufficient. It doesn't cover behavioral aspects like reversibility, error conditions, or response format, leaving the agent with incomplete context for safe and effective use.

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 schema description coverage is 100%, so the schema already documents all parameters (email_id, folder, trash_folder) with clear descriptions. The description adds no additional meaning beyond what the schema provides, such as explaining parameter interactions or default behaviors, resulting in a baseline score of 3.

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 action ('Move') and resource ('an email to trash folder'), making the purpose immediately understandable. However, it doesn't differentiate this tool from its sibling 'batch_move_to_trash' or 'delete_email', which perform similar operations, so it doesn't reach the highest score for sibling distinction.

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?

The description provides no guidance on when to use this tool versus alternatives like 'batch_move_to_trash' for multiple emails or 'delete_email' for permanent deletion. It lacks context about prerequisites, such as whether the email must be accessible or if specific permissions are needed, leaving the agent with minimal usage direction.

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