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 usefully adds that the tool uses 'cached sync metrics (no live IMAP)', clarifying it doesn't perform live checks. However, it doesn't describe the return format, whether it requires specific permissions, rate limits, or error conditions, leaving gaps for a read operation 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, efficient sentence that front-loads the core purpose and includes a critical behavioral detail ('no live IMAP'). Every word earns its place with no redundancy or fluff, making it highly concise and well-structured.

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 tool's moderate complexity (read operation with one optional parameter), no annotations, and no output schema, the description is partially complete. It covers the purpose and a key behavioral trait but lacks details on return values, error handling, or permissions. This is adequate but has clear gaps for an agent to use it effectively.

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 has 100% description coverage, so the baseline is 3. The description adds value by explaining the optional parameter's semantics: 'for all accounts or a specific account', which clarifies that omitting 'account_id' returns health for all accounts. This goes beyond the schema's 'optional' note, earning a higher score.

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 tool's purpose: 'Get sync health status for all accounts or a specific account based on cached sync metrics (no live IMAP).' It specifies the verb ('Get'), resource ('sync health status'), and scope ('all accounts or a specific account'), but doesn't explicitly differentiate from sibling tools like 'get_sync_history' or 'check_connection', which prevents 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 implies usage context by mentioning 'cached sync metrics (no live IMAP)', suggesting this is for checking historical/background sync status rather than real-time connectivity. However, it doesn't provide explicit guidance on when to use this versus alternatives like 'check_connection' or 'get_sync_history', nor does it state any prerequisites or exclusions.

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