MCP Email Service

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 states the tool 'gets' content, implying a read-only operation, but doesn't specify if it requires authentication, has rate limits, returns structured data or raw content, or handles errors. For a tool with no annotations, this leaves significant gaps in understanding its behavior.

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 fluff. It is appropriately sized and front-loaded, with every word contributing to understanding the core function.

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 email operations and the lack of annotations and output schema, the description is incomplete. It doesn't explain what 'detailed content' includes (e.g., headers, body, attachments) or the return format, which is critical for an agent to use the tool effectively. The description should compensate for these gaps but doesn't.

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 100%, so the schema already documents both parameters (email_id and folder with default 'INBOX'). The description adds no additional meaning beyond implying that email_id identifies the specific email, which is already clear from the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 verb 'get' and the resource 'detailed content of a specific email', which distinguishes it from siblings like list_emails (which lists multiple emails) or get_unread_count (which provides counts). However, it doesn't explicitly differentiate from tools like mark_email_read that also operate on specific emails, keeping it from a perfect score.

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. For example, it doesn't clarify if this should be used after list_emails to get details for a specific email ID, or if there are prerequisites like needing the email_id from another operation. No exclusions or alternatives are mentioned.

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